to do tomorrow. Wouldn't that entail that tomorrow you must do what it
was known in advance that you would do? In spite of your deliberating
and planning, in the end, all is futile: you must choose exactly as it
was earlier known that you would. The supposed exercise of your free
will is ultimately an illusion. Historically, the tension between
foreknowledge and the exercise of free will was addressed in a
religious context. According to orthodox views in the West, God was
claimed to be omniscient (and hence in possession of perfect
foreknowledge) and yet God was supposed to have given humankind free
will. Attempts to solve the apparent contradiction often involved
attributing to God special properties, for example, being "outside" of
time. However, the trouble with such solutions is that they are
generally unsatisfactory on their own terms. Even more serious is the
fact that they leave untouched the problem posed not by God's
foreknowledge but that of any human being. Do human beings have
foreknowledge? Certainly, of at least some events and behaviors. Thus
we have a secular counterpart of the original problem. A human being's
foreknowledge, exactly as would God's, of another's choices would seem
to preclude the exercise of human free will. Various ways of trying to
solve the problem – for example, by putting constraints on the
truth-conditions for statements, or by "tightening" the conditions
necessary for knowledge – are examined and shown not to work.
Ultimately the alleged incompatibility of foreknowledge and free will
is shown to rest on a subtle logical error. When the error, a modal
fallacy, is recognized, and remedied, the problem evaporates.
1. Introduction: The Problem of Foreknowledge and Free Will
Moses Maimonides (1135-1204) has set out the problem in the traditional manner:
… "Does God know or does He not know that a certain individual
will be good or bad? If thou sayest 'He knows', then it necessarily
follows that [that] man is compelled to act as God knew beforehand he
would act, otherwise God's knowledge would be imperfect.…"[1]
The argument can be extended. The thrust of the argument does not
apply only to doing good or ill, but indeed to every human act, from
the most mundane to the most significant. The argument could just as
well read:
"Does God know or does He not know that a certain individual
(let's say the Prime Minister of Canada), on Feb. 3, 2081, will put on
brown shoes when dressing in the morning? If thou sayest 'He knows',
then it necessarily follows that the Prime Minister is compelled to
act (i.e. to put on brown shoes) as God knew beforehand he/she would,
otherwise God's knowledge would be imperfect. …"
The argument for the seeming impossibility of both God's having
foreknowledge and our having free will has troubled religious
thinkers, philosophers, and jurists for centuries.
It is clear why theologians are troubled by the challenge of
foreknowledge and free will. For most religions insist that God has
given human beings free will and thus human beings can choose right
from wrong, and that (in some religions at least) wrongful acts are
sinful and worthy of divine punishment, while good acts are righteous
and worthy of divine reward. But many of these same religions will
also insist that God is omniscient, i.e. God knows everything (and
thus has perfect foreknowledge).[2] To deny either of these claims –
that human beings have free will or that God is omniscient – amounts
to heresy. Yet, on the face of it, each of these two claims appears to
contradict the other.
But why should secular philosophers and jurists also be concerned with
this conundrum? For two reasons.
First is that many, perhaps most, contemporary philosophers and
jurists are keen to preserve the viability of the concept of free
will. Our legal institutions, our very sense of what is praiseworthy
and what is blameworthy, turn on the notion of free will. It is at the
conceptual bedrock of our civilization that persons are creatures
having the capacity of deliberation, that we have the ability to
recognize right from wrong, that we have the ability to choose (to a
large extent) what we do (and what we do not do), and – most
especially – we are responsible for what we choose to do (and
responsible for what we choose not to do).
Second is that the challenge to the existence of free will is posed
not just by God's foreknowledge but by any foreknowledge whatsoever.
The religious version of the puzzle arises because God is said to have
omniscience, i.e. knowledge of everything. But the problem would arise
if anyone at all (i.e. anyone whatsoever) were to have knowledge of
our future actions. This generalized version of the problem has come
to be known as the problem of Epistemic Determinism. For example, if
my wife were to know today that I would choose tea (rather than
coffee) for my breakfast tomorrow, then one could argue (paralleling
Maimonides's argument) that it would be impossible for me not to
choose tea tomorrow at breakfast.
The two concepts – (i) foreknowledge and (ii) human freedom – seem to
be utterly incompatible. The challenge, then, i.e. the problem posed
by epistemic determinism, is to find a way to show that
either (1) foreknowledge (of human beings' future actions) does not exist;
or (2) free will does not exist;
or (3) the alleged logical relation between foreknowledge and the
exercise of free will is mistaken (i.e. foreknowledge is not
incompatible with the exercise of free will).
Historically, some theologians have tried to solve the puzzle by
invoking unique properties of God. For example, some have argued that
God is 'outside of time' (or that 'His knowledge is timeless') and
thus His knowledge is not foreknowledge at all, i.e. God's knowledge
does not occur before (or during, or after, for that matter) any
events in the world. The trouble with such solutions is (a) they leave
non-theistic versions of the puzzle untouched (e.g. my wife's knowing
that I will drink tea tomorrow), and (b) we can construct a revised
version of the puzzle explicitly invoking God's timelessness, e.g.
God is omniscient and His knowledge is timeless, i.e. God knows
timelessly all that has happened, is happening, and will happen.
Therefore, if He knows timelessly that a person will perform
such-and-such an action, then it is impossible for that person not to
perform that action.
Some other theologians have argued that God has a 'special way' of
knowing. Unlike human beings (and other sentient creatures) who must
causally interact with the world (e.g. read a report, see an event,
examine evidence [such as ashes, skid marks, etc.]), God is said to
'know directly', i.e. without the need of sensory data or of physical
interaction with the world. Such a notion of 'direct knowledge' is
problematic in itself; but more importantly, it is hard to see how it
solves the problem at hand, indeed how it even addresses the problem.
For, again, as was the case with arguing that God's knowledge is
outside of time, the same two objections can be raised to this
putative solution: (a') this latter attempted solution leaves the
non-theistic version of the puzzle untouched; and (b') we can
construct a revised version of the puzzle explicitly invoking God's
'direct knowledge', e.g.
God knows directly (i.e. without sensory data) all that has
happened, is happening, and will happen. Therefore, if He knows
directly that a person will perform such-and-such an action, then it
is impossible for that person not to perform that action.
Contemporary philosophers, especially secular ones, seek a solution
elsewhere. We are disinclined to pursue solutions that call upon
special properties of God, especially since any such solution leaves
the 'secular' version of the problem untouched.
The focus of attention has shifted dramatically. Secular philosophers
argue that the supposed incompatibility arises out of a very subtle
but seductive logical fallacy. So unobvious is this fallacy that it
escaped detection by Maimonides and hundreds (perhaps even countless
thousands) of other persons. The error has come to bear the name "The
Modal Fallacy".
However, before we examine the Modal Fallacy, we need to delve deeper
into the notions of determinism,truth, and knowledge.
2. Three Kinds of Determinism
There are three distinct versions of determinism: logical, epistemic,
and causal. Each has been alleged to pose a threat to the exercise of
free will, indeed it has been claimed of each version that its
existence is incompatible with the existence of free will.
1. Logical determinism is most frequently couched as the problem of
'future contingents'. The threat to the exercise of free will arises
from the thesis that the truth-value (i.e. the truth or falsity) of
any proposition[3] is timeless, i.e. those propositions that are true
are always true, and those propositions that are false are always
false. Thus:
If a proposition about some future action you undertake (let's say
tomorrow) is true, then it is true now. But if it is true now, then
tomorrow you must undertake that action, that action must occur, you
are powerless to prevent yourself from undertaking that action.
(Note that "logical" in the phrase "logical determinism" is not meant
to contrast with "illogical", but instead refers to a particular
concept of logic, namely truth itself.)
2. Epistemic determinism has a strikingly similar formulation. Instead
of simply attributing truth (or falsity) to propositions about the
future, epistemic determinism concerns such propositions' being known
prior to the times of the occurrences they refer to. We then get this
argument, parallel to the preceding one:
If a proposition about some future action you undertake is known
(in advance), then (when the time comes) you must undertake that
action, that action must occur, you are powerless to prevent yourself
from undertaking that action.
3. Causal determinism is the thesis that all events (occurrences,
processes, etc.) are the result of Laws of Nature and of antecedent
conditions and of nothing else. Thus (to cite an example made famous
by Carl Hempel), when a car radiator cracks overnight, it is the
consequence of laws pertaining to the tensile strength of iron, of
laws pertaining to the expansion of water upon freezing, to the
structure of the radiator, to its being filled with water without
anti-freeze, and to the temperature's falling well below freezing for
several hours.[4] In the case of human beings' acting, the same
scenario is said to obtain.
If whatever one does is the result of Laws of Nature and of one's
physical and genetic makeup and one's personal history, then – since
all these 'factors' are 'set' (or 'in place') at the moment of one's
acting – you must undertake the action you perform, that action must
occur, you are powerless to prevent yourself from undertaking that
action.
Three arguments all with the same conclusion, namely that your actions
are 'determined' (in one of three different ways) and thus your
actions are 'unfree'. Free will is an illusion.
Of the three deterministic arguments, the most difficult to engage is
the third, that of causal determinism. Indeed, so knotted is that
argument, and so contentious are the issues surrounding its
presuppositions, it is treated separately in this Encyclopedia. (See
e.g. "Laws of Nature.")
Note: From this point on, this article will examine only Epistemic
Determinism and Logical Determinism.
3. The Relationship Between Epistemic and Logical Determinism
Since the ground-breaking work of Plato (427?-347? B.C.E.) most
philosophers have agreed that there are (at least) three conditions
that must be satisfied for a human being, let's say "x", to have
knowledge of matters of fact, let's say "P":
1. P (is true)
2. x has good evidence, e, that P (and has little, or no,
countervailing evidence)[5]
3. x believes, on the basis of e, that P
In the case of God, one may want to drop the second condition, the
evidential requirement, allowing that God knows directly without the
need of evidence. The third condition, the belief-condition, poses
certain problems as well. In the case of human beings, this condition
captures the 'mental' or 'cognitive' aspect of knowledge. But the
beliefs of an omniscient God are unlike those of human beings. The
beliefs of human beings are finite, shifting, fallible, and
corrigible. Those of an omniscient God are infinite, unchanging,
infallible, and incorrigible. Perhaps, then, "believes" is not quite
the right word to use when speaking of God's knowledge, but no other
is ready at hand.
Be this as it may, there remains one common element (at least) in the
case of a human being's having knowledge and God's having knowledge,
namely what is known is true. Neither God nor any human being can
literally know anything that is in fact false. Put another way, truth
is a prerequisite of knowledge (or using the vocabulary of logic,
truth is a necessary condition for knowledge).[6] Someone may believe
strongly that some proposition is true, indeed he may insist that he
knows, he may insist that he has incontrovertible evidence that that
proposition is true, but if that proposition is in fact false, then he
does not know. (This is not to say that he must have some way of
finding out that he is mistaken. We are here divorcing truth from
belief.) Every proposition that is genuinely known (i.e. to be true)
is true; but the converse – namely that every proposition that is true
is known – certainly does not hold for less-than-omniscient human
beings.
The upshot is that the premises of the argument for Epistemic
Determinism (i.e. that there can be knowledge of some [at least] of a
person's future actions) presuppose the premises of the argument for
Logical Determinism. For, simply, if there is knowledge now (i.e.
prior to the occurrence) of some future actions, then there are
propositions about the future that are true now. If one were able to
reject the premises of the argument for Logical Determinism, one would
thereby render the argument for Epistemic Determinism unsound.
4. Attacking the Premises of Deterministic Arguments
As is the case with any argument, four responses are possible.
1. One can accept the argument. In effect, this is to say that one
regards the argument as being sound, i.e. as having true premises and
as being valid.
2. One can argue that although the argument is valid, its
premise-set is false (and thus its conclusion is unsupported).
3. One can reject the validity of the argument, in particular by
arguing that although the premise-set is true, the conclusion does not
follow from that premise-set.
4. Finally, one can adopt both of the immediately preceding two
strategies, i.e. argue that not only is the premise-set false, the
argument is invalid to boot.
Some religious groups, e.g. the early Calvinists, have adopted the
first option. They accept the soundness of the deterministic arguments
and – giving primacy to God's knowledge over human beings' free will –
argue that free will does not exist.
Needless to say, very few others have been inclined to adopt such a
view, indeed most persons who are familiar with the deterministic
arguments are strongly motivated to rebut such a view. Such persons
will, therefore, examine the possibility of adopting option 2 or 3. We
turn, then, first, to see whether one can cogently rebut the premises
of the argument for Logical Determinism.
a. Can a Future Contingent be true prior to the event it refers to?
Propositions about future events, or, if one prefers, about future
matters of fact, are known as future contingents. The earliest
discussion of future contingents, and the attendant problem of logical
determinism, occurs in Aristotle's De Interpretatione 9.[7] There,
Aristotle discusses the case of 'Tomorrow's Sea Battle'. His argument,
reconstructed and embellished, is this:
Two warring admirals, A and B, are preparing their fleets for a
decisive sea battle tomorrow. The battle will be fought until one side
is victorious. But the 'logical laws (or principles)' of the excluded
middle (every proposition is either true or false) and of
noncontradiction (no proposition is both true and false), require that
one of the propositions, 'A wins' and 'it is false that A wins', is
true and the other is false. Suppose 'A wins' is (today) true. Then
whatever A does (or fails to do) today will make no difference: A must
win; similarly, whatever B does (or fails to do) today will make no
difference: the outcome is already settled, i.e. A must win. Or again,
suppose 'A wins' is (today) false. Then no matter what A does today
(or fails to do), it will make no difference: A must lose; similarly,
no matter what B does (or fails to do), it will make no difference:
the outcome is already settled, i.e. A must win. Thus, if every
proposition is either true or false (and not both), then planning, or
as Aristotle put it 'taking trouble', is futile. The future will be
what it will be, irrespective of our planning, intentions, etc.
How might one try to rebut the premises of Aristotle's argument?
Proposal One: One might argue that propositions are not true in
advance of the events described. Propositions 'become' true when the
events described occur.
First objection to Proposal One: (i) Sirhan Sirhan killed Robert F.
Kennedy. But when did it 'become true' that Sirhan Sirhan killed
Kennedy? At the moment of his pulling the trigger? But the bullet was
not yet lodged in Kennedy's body. At the time of the bullet's entering
Kennedy's body? But Kennedy did not die immediately. He was rushed to
a hospital where he died some hours later. At the moment of Kennedy's
death? But at that moment Sirhan Sirhan was in the custody of police
in a building remote from the hospital where Kennedy was. (This
conundrum is the handiwork of Judith Jarvis Thomson.[8] ) The point is
that although it is clearly true that Sirhan Sirhan killed Kennedy, it
is problematic to pin down an exact time (or even a candidate for the
exact time) when Sirhan killed Kennedy and, by extension, when it
'became true' that Sirhan killed Kennedy. (ii) When did Germany lose
World War II? When the Allies' invasion force landed on the beaches of
Normandy? When British scientists and engineers invented and were able
to use radar against the German Luftwaffe? When Alan Turing and his
team broke the German secret code? When …?
The issues in the preceding paragraph strongly suggest that it will
prove problematic in the extreme to try to put precise times on the
(supposed) occurrence of a proposition's 'becoming true'. Moreover,
propositions are supposed to be abstract entities, entities which do
not exist in space and time; but if they do not exist in time, how can
their properties change – from being neither true nor false to being
true (or to being false as the case may be) – at some particular time?
Second objection to Proposal One: We do, in a great many cases,
routinely ascribe truth to propositions about future events. (iii)
Each year the Children's Hospital in Vancouver has a lottery in which
the grand prize is a new 'prestige home'. Persons buy tickets on the
firm belief that some winning ticket will be drawn. If the Hospital
deliberately failed to draw a ticket, on the scheduled date, from the
pool of purchased tickets, all those who had purchased a ticket could
rightly claim that the hospital had been lying, i.e. had been
asserting false propositions. The ticket-holders had all assumed that
the proposition "Some winning ticket will be drawn on the scheduled
date" was true, weeks before the scheduled date. (iv) It is true today
that there will a US presidential election in 2048. And (v) it is
demonstrably true now that there will be a total solar eclipse, over
parts of Libya and Turkey, on 30 April 2060.[9]
Third objection to Proposal One: To argue that propositions about the
future acquire a truth-value only when the described event occurs
(i.e. in the future) will entail abandoning the logical law
(/principle) of the excluded middle: propositions about the future
will not, then, have truth-values now, i.e. prior to the occurrence of
the predicted event. Adopting Proposal One would require our creating
a far more complicated logic. This is not to say that this proposed
solution is completely without merit; but it is to say that we ought
to try to find some other solution before resorting to such a major
revision of logic. [For more discussion of these objections, see Time:
Is the future real?.]
What other way might one, then, propose to avoid the conclusion of the
argument about tomorrow's sea battle?
Proposal Two: Disjunctions (i.e. propositions of the form "P or Q" [in
this particular case "A wins or it is false that A wins"]) are true,
but not the individual disjuncts (components, i.e. "A wins" and "it is
false that A wins").
Objection to Proposal Two: The proposal is terribly peculiar. We are
inclined to say that a disjunction is true just because (at least) one
of its disjuncts is true. If neither P is true nor Q is true, how can
"P or Q" be true? And, further, just as in the previous proposal, this
one, too, entails abandoning the law of the excluded middle: while "A
wins or it is false that A wins" has a truth-value now, neither of the
two propositions "A wins" and "it is false that A wins" has a
truth-value now. So, once again, we would prefer a less radical
solution.
Interim Conclusion #1: It emerges, then, that challenging the premises
of the argument for logical determinism – namely that a proposition
about an event can be true prior to the occurrence of that event – is
not a promising approach to solving the problem of the threat posed to
the existence of free will. (We will return to a further examination
of Logical Determinism in due course.) Since truth is a necessary
condition for knowledge, if we had been able to reject the premises of
the argument for logical determinism, we would, thereby, at a stroke
have undercut the argument for epistemic determinism. But, at this
point in our discussions, we are allowing that future contingents can
be true (or false) now, prior to the events referred to. Thus we must
next examine whether the premises of the argument for epistemic
determinism can be true.
b. Can a Future Contingent be known prior to the event it refers to?
How might one try to rebut the premises of the argument for epistemic
determinism?
Proposal One: One might argue that factual propositions are knowable
only through a causal chain linking the event to the would-be knower.
One can know, for example, that Mount St. Helens erupted within the
last one hundred years: by hearing the reports of eyewitnesses, by
seeing the event on television, by reading newspaper accounts, and by
viewing the very considerable damage to the environs of the mountain.
In short, we know of events by their causal remnants and since there
apparently are no cases of 'backwards causation', knowledge of future
contingents is impossible.
Objection to Proposal One: Even if it is granted that there are no
causal remnants of future events, the conclusion that there can be no
knowledge of future events is false. Examining their remnants is not
the only way to have knowledge of future events. In the case of Mount
St. Helens, for example, ample warning was given (a month earlier) by
the US Forestry Service of the imminent cataclysm. Some of those who
choose to ignore the danger signals did not live long to regret their
folly.
And it is not only of impending large-scale disasters that we often
have foreknowledge. Throughout our normal, even humdrum, days we
depend on our knowledge of future contingents in order to maintain our
lives and to avert death. When we see a bus traveling at a high speed
along a highway on whose curb we are standing, we know full well that
that bus is going to pass in front of us and that it would kill us if
we were to be foolhardy enough to step in front of it just as it
approached. None of us expects the bus suddenly, as it approaches, to
turn into a slow-moving marshmallow. We know that the bus will retain
its 'integrity' as a bus. Even such a simple, commonplace, act as
unceremoniously opening and drinking a bottle of cola requires our
knowing that it will not poison us, that it is, and will remain,
potable.
Simply put, our knowledge of how the world has behaved up till now
provides powerful evidence of how it will behave. That is why we teach
our children not to play in the street, why we teach our children not
to put their fingers into electrical outlets, why we (try to) teach
our children not to drive while intoxicated, etc. Our daily behavior
provides abundant and powerful evidence that we do, to a very great
extent, know perfectly well what the future will be.
Proposal Two: The examples offered in the objection (immediately
above) are not bona fide cases of foreknowledge; they are cases merely
of strong beliefs. We may believe we know, but something 'could go
wrong' between now and the predicted event. We cannot rule out our
making a mistake. There is always the ineliminable possibility of
error. For example, the person who opens and drinks a bottle of cola
doesn't really know that it is safe to drink, that someone hasn't in
fact tampered with the drink and poisoned it. Because of the
possibility of unforeseen circumstances, even if they are very
improbable, one cannot have genuine knowledge of the future.
First Objection to Proposal Two: Knowing a future contingent does not
require that there be no possibility of our making a error. Yes, we
could make a mistake, yes, something might happen that will make our
prediction turn out false, but that is no reason to claim that we
cannot know the future. What is required is that we have good grounds
to make our prediction and that they be true, not that there be no
possibility of error.
At the dawn of the 'modern' era in philosophy, René Descartes
(1595-1649) began his Meditations by asking what could be known for
certain. He sets as his program the elimination from his belief-system
all that is not, or cannot be, known for certain.
My reason tells me that as well as withholding assent from
propositions that are obviously false, I should also withhold it from
ones that are not completely certain and indubitable.[10]
Given the tenor of his time, with the extraordinary success of the
'new' science, the headiness of such a claim is perhaps understandable
(and forgivable). But it was, in the end, a colossal error. It was the
pursuit of an impossible goal, the philosophical equivalent of placing
the goalposts in an unreachable place.
The two phrases "x knows" and "x knows for certain" are no more
equivalent than "x sees the distant mountain" and "x sees the distant
mountain perfectly (e.g. from miles away x can see the veins in the
leaves on the trees)". Persons who do not have perfect pitch may,
nonetheless, know when a pianist has hit a wrong note. One doesn't
have to hear perfectly to hear. Two mathematicians may prove the same
theorem; one of these proofs may be 'elegant', the other 'circuitous';
but both are proofs. A proof need not be elegant in order to be proof.
Similarly with knowledge. What one knows need not be certain; some,
probably most, things that we know fall short of certainty, but it is
arbitrary and stultifying to refuse to acknowledge these cases as
genuine cases of knowledge. By setting the standards too high, as did
Descartes and as do many of his intellectual heirs even today, is to
rob the concept of "knowledge" of its utility.
To know the future, it is not required that we be infallible (i.e.
incapable of making a mistake). The person who sees a bus fast
approaching knows that it will not (miraculously) turn into a
marshmallow. And she is right: it does not. Realistically, few of us
(unless corrupted by a bad introductory philosophy course), would be
tempted to say, "She didn't know. After all, the bus could have turned
into a marshmallow." True enough, there is one sensein which the bus
could have turned into a marshmallow, and that sense is that such an
eventuality is a logicalpossibility, i.e. is not logically
self-contradictory. Indeed it is a matter of the very definition of
"matter of fact" or "contingency" that such propositions are both
possibly true and possibly false. Every true contingency is (as a
matter of the very definition of "contingency") possibly false; and
likewise every false contingency is (as a matter of the very
definition of "contingency") possibly true. [More on this in section 5
below.] But nothing of particular significance follows from these
latter facts.
One must be careful not to 'slide' from "possible" to "probable". Just
because an event is possible does not justify the inference that it is
probable. The proposition that the US Congress will adopt Swedish as
the country's sole national language certainly is a logical
possibility, i.e. is not self-contradictory. But that proposition has
a probability, for all intents and purposes, of zero. Every contingent
proposition is both possibly true and possibly false. And some
propositions that are possibly false have a reasonably high
probability of being actually true; while some (other) possibly false
propositions have a (nearly) zero probability (/zero likelihood) of
being true. The essential point for our knowing a contingent
proposition is (a) our having a well-founded belief that it is true
and (b) that it is true. Its being possibly false is irrelevant. Its
being probably false is quite another matter, but whether it is
probably false or is not probably false is not entailed by its being
possibly false.
Every true contingency whatsoever, not just those about the future, is
possibly false. It is truth that counts, not possible falsehood.
Actual truth 'trumps' possible falsehood in the matter of a
proposition's being known.
Second Objection to Proposal Two: One must be careful not to set the
requirements, for knowing the future, unrealistically high. For such
standards can rebound and make it impossible to know the past as well.
In the first decade of the Twentieth Century, the conductor and
musicologist, Friedrich Wilhelm Stein, discovered in Jena, Germany, a
copyist's version of a formerly unknown symphony. The copyist had
annotated it as having been written by Beethoven. It was published in
1911 as Beethoven's "Jena Symphony". However, in 1957, H.C. Robbins
Landon uncovered the original manuscript and established that the
composition had in fact been written by Friedrich Witt (1770-1837), a
contemporary of Beethoven's.
Clearly those who believed, in the years 1911 through 1947, that the
"Jena Symphony" had been composed by Beethoven had a well-grounded
belief. But, as it was to turn out, their belief was mistaken. And
this little piece of history demonstrates how what we take to be
knowledge of past events can be mistaken. But what moral should one
draw from this story?
Although we can never eliminate entirely the possibility of our having
mistaken beliefs about past events, or misleading (or incorrect)
evidence for those beliefs, it does not follow that we do not have
knowledge of a great many past events. There is, to cite just one
instance, simply too much evidence, indeed overwhelming evidence, that
Mount St. Helens erupted on 18 May 1980 for anyone to have a rational
belief that we do not know that historical fact. To be sure, it is
logically possible that we should be mistaken. But the probability
that we are mistaken is effectively zero.
If we are to be skeptical about the possibility of knowing any future
events, we would have to be equally skeptical of our knowledge of the
past. And if we are not unduly skeptical about our knowledge of the
past, we ought not to be unduly skeptical about the possibility of our
knowing certain future events. (And as for the claim that we know far
more about the past than we do of the future, one must bear in mind
that we know only an infinitesimal part of what has happened in the
past. Do you know, or indeed have any way of finding out, for example,
the names of Leif Ericson's shipmates?)
Understand that I am not being especially skeptical about the past.
All I am trying to do is to draw a parallel between knowledge of the
past and knowledge of the future. The parallels are these: in both
sorts of cases it is possible to have very strong evidence; in both
sorts of cases it is possible to be mistaken. Possibly being mistaken
is not a condition unique to claims about knowing the future; it
applies equally to claims about knowing the past. But in neither case
does the possibility of error undermine truth.
Proposal Three: The examples that have been given of foreknowledge,
e.g. of a solar eclipse, of an imminent volcanic eruption, of a US
presidential election, etc., are cases of naturally occurring
phenomena or of legislatively mandated events. Such events have an
overwhelmingly high probability of occurring. But when we turn to
cases of human beings making choices, the situation is vastly
different.
Many, perhaps most, human choices and behaviors are the product of
free will. Some of these choices and behaviors are conscious and
deliberative considerations; others are subject to whim, to irrational
desires, to spur-of-the-moment decisions, etc. None of us can know, in
advance, what another person's free choice will be.
Objections to Proposal Three: This latter way of trying to undercut
the premises of the argument for Epistemic Determinism works, if at
all, only for the secular version. It does nothing to diminish the
sting of the version capitalizing on God's omniscience.
But even if this objection is confined to the secular version, it
hardly addresses the alleged conundrum. For the secular version of the
argument for Epistemic Determinism does not, in the slightest, require
that we human beings be able to foresee all the actions and behavior
of other persons. The argument has its dreadful bite even if we are
able to foresee only some of the free choices of others. And being
able to do that is something that is familiar to everyone.
In the case of persons whom we know well, especially family members,
we are able to know, in certain circumstances, what they are about to
say or do. If my wife and I go to dinner at one particular restaurant,
I know beforehand, without her telling me, what she will order for
dessert (lemon pie). If I happen to glance at her shopping list before
she leaves home, I can know in advance that she will return with some
60-watt light bulbs. All of these are free choices on her part; none
of them is coerced or forced in any way. Yet, I do know them.
In the case of predicting the behavior of groups of persons, entire
industries have grown up in the last 100 years devoted to such
inquiries: professional pollsters, of course, but also economists,
psychologists, political commentators, planning departments of large
corporations, marketing advisers, pension-fund managers, etc.,
operating under a number of context-relevant constraints, e.g. to
minimize losses, to maximize gains, etc. Perhaps nowhere is such
research of greater consequence than in planning military maneuvers
(as in World War II). On that occasion, it became a matter of life and
death for countless numbers of troops that their commanders correctly
predicted the actions of their enemies.
Interim Conclusion #2:
Earlier we saw that there are no good reasons to reject the claim that
future contingents are true (or false as the case may be) prior to the
occurrence of the events they refer to. And now we see that,
similarly, there are no good reasons to reject the claim that many
future contingents (all future contingents in the case of God) can be,
and more especially are, known prior to the events they refer to.
Thus, if we are, finally, to remove the sting of the deterministic
arguments, we will have to do so by arguing that these arguments,
although having true premises, are – appearances to the contrary –
invalid. Each of these arguments harbors a logical slip between their
premises and their conclusions. The rest of this article is given over
to revealing the nature of the logical error.
5. Possibility, Necessity, and Contingency
To expose the mistakes in the deterministic arguments, we will need
some tools of modern logic. Some elementary symbols will help to
illuminate the concepts at play in the deterministic arguments.
However, all the formulas that will be used, which incorporate these
symbols, will also be expressed in English prose.
Symbol Its meaning Explanation
P, Q, R, … propositions See footnote 3
~P it is not the case that P Example: It is not the case that copper conducts
electricity. (Note: "P" and "~P" have opposite
truth-values – whichever is true, the other is
false.)
P ⊃ Q if P, then Q Example: If she is late, (then) the meeting will be
delayed.
gKP God knows that P Example: God knows that the Mississippi River flows
north to south.
Next we need three concepts at the heart of modern modal logic. The symbols are:
Symbol Its meaning Explanation
◊P it is (logically) possible that P Example: It is (logically)
possible that the United
States was defeated in World War II. (Note: Whatever
is not self-contradictory is logically possible.)
☐P It is (logically) necessary that P Example: It is logically
necessary that every number has
a double. (Note: If Q is not logically possible, then
~Q is logically necessary.)
∇P It is contingent that P Example: It is contingent that the United States
purchased Alaska from Russia.
(Note: A proposition, Q, is contingent if and only if
◊Q and ◊~Q.)
These latter three concepts require further elaboration.
P is possible (symbolized "◊P"). A proposition, P, is possible if and
only if it is not self-contradictory. All propositions that are true
are possibly true. In addition, some false propositions are also
possibly true, namely those that are false but are not
self-contradictory. Some philosophers like to explicate "P is
possible" in this way: "There are some possible circumstances in which
P is true". And some philosophers, adopting the terminology
popularized by Leibniz (1646-1716), will substitute "worlds" for
"circumstances", yielding "P is true in some possible worlds".
Examples of possibly true propositions include:
1. Ottawa, Canada, is north of Washington, DC.
2. The Great Salt Lake is saltier than the Dead Sea.
3. The Dead Sea is saltier than the Great Salt Lake.
4. John Lennon was the first songwriter to travel in a space capsule.
5. There are three times as many species of insect as there are
species of mollusk.
6. 2 + 2 = 4
7. All aunts are female.
8. Some pigs can levitate.
Understand that prefacing a proposition, P, with "◊" does not 'make' P
possible. What it does is to create a new, different, proposition,
namely ◊P, which, in effect, says that P is possible. If P is possible
(e.g. suppose "P" stands for "Gold was first discovered in California
in 1990″), then (although P is false), ◊P is true. Or, suppose "Q"
stands for "2 + 2 = 7″. Then prefacing "Q" with "◊" does not 'make' Q
possible. It produces a new proposition, "◊Q", which is false. Q is,
and remains, impossible whether or not it is prefaced with "◊".
Everything that is actual (or actually true) is possible (i.e.
possibly true). But if a proposition is actually false, then it is
impossible only if it is self-contradictory; otherwise it is a false
contingency, and all contingencies, whether true or false, are
possible.
We may ask "What color did Sylvia paint the lawn chair?" We look at
the chair and see that she has painted it yellow. Thus it is
demonstrable that it is possible that she painted the chair yellow.
And its being yellow implies it is false that she painted the chair
blue. But the falsity of the proposition that she painted the lawn
chair blue in no way precludes that she could have done so. Even
though false, it still remains possible that she painted the chair
blue.
P is necessary (symbolized "☐P"). Necessarily true propositions are
those that are true in all possible circumstances (/worlds), i.e. are
not false in any. Necessary truth can be defined in terms of
possibility, namely P is necessary if and only if its negation (i.e.
"~P") is impossible. In symbols (where "=df" stands for "is by
definition"):
☐P =df ~◊~P
Examples of necessarily true propositions:
1. 2 + 2 = 4
2. All aunts are female.
3. Whatever is blue is colored.
4. There are either fewer than 20 million stars or there are more
than 12 million. (This statement may be unobvious; but if you think
about it you may come to see that it cannot be false.)
5. It is false that some triangle has exactly four sides.
P is contingent (symbolized "∇P"). A proposition, P, is contingent if
and only if it is both possibly true andpossibly false. Contingent
propositions are those that are true in some possible circumstances
(/worlds) and are false in some possible circumstances (/worlds).
Contingency can be defined in terms of possibility, namely:
∇P =df ◊P & ◊~P
It is essential to understand that "◊P & ◊~P" does not mean "P is true
and false in some possible circumstances (worlds)". No proposition
whatsoever is both true and false in the same set of circumstances
(law of non-contradiction). To say that a proposition is contingent is
to say that it is true in some possible circumstances and is false in
some (other!) circumstances.
Examples:
1. The Boston Red Sox won the World Series in 2002.
2. It is false that the Boston Red Sox won the World Series in 2002.
3. Steel-clad ships can float in the ocean.
4. It is false that steel-clad ships can float in the ocean.
Modal terms and modal status
Terms such as "must", "has to", "cannot", "is necessary", "is
impossible", "could not be otherwise", "has to be", "might", "could
be", "contingent", and the like, are known as "modal" terms. All of
these are definable in terms of "possibility".
Every proposition is either logically possible or logically
impossible. And no proposition is both.
Drawing the net a bit finer, and dividing the class of logically
possible propositions into those that are necessarily true and those
that are contingent, we have three exclusive categories. Every
proposition is exclusively either necessarily true, necessarily false,
or contingent. That is, every proposition falls into one of these
latter three categories, and no proposition falls into more than one.
Just as the expression "truth-value" is a generic term encompassing
"truth" and "falsity", the expression "modal status" is a generic term
encompassing "contingent", "necessarily true", and "necessarily
false".
Finally, no proposition ever changes its modal status. We will call
this principle "The Principle of the Fixity of Modal Status". And for
the purposes of assessing the deterministic arguments we note
especially: no contingent proposition ever 'becomes' necessary or
impossible.
6. The Modal Fallacy
From a mathematical point of view, if we arbitrarily pick any two
propositions, truth and falsity can be attributed to them in four
different combinations, specifically
* the first is true, and the second is true
* the first is true, and the second is false
* the first is false, and the second is true
* the first is false, and the second is false
However, it sometimes happens that two propositions will have certain
logical relationships between them such as to make one or more of
these four combinations impossible. For example, consider the two
propositions α and β.
α: Diane planted only six rosebushes.β: Diane planted fewer than
eight rosebushes.
While each of these propositions, by itself, could be true and could
be false, there are – as it turns out – only three, not four, possible
combinations of truth and falsity that can be attributed to this
particular pair of propositions. On careful thought, we can see that
the second combination – that is, the one which attributes truth to α
and falsity to β – is impossible. For if α is true (i.e. if it is true
that Diane has planted only six rosebushes) then β is also true. Put
another way: the truth of α guarantees the truth of β. This is to say
(1) It is impossible (for α to be true and for β to be false).
Unfortunately, ordinary English does not lend itself easily to express
the quasi-symbolic sentence (1). In symbols we can express the
sentence this way:
(1a) ~◊(α & ~β)
About the best we can do in English is to create the following
unidiomatic, extremely clumsy sentence:
(1b) The compound sentence, α and not-β, is impossible (i.e. is
necessarily false).
English prose is a poor tool for expressing fine logical distinctions
(just as it is an unsuitable tool for expressing fine mathematical
distinctions[11] ). But, as it turns out, the situation is worse than
just having to make do with awkward sentences. For it is a curious
fact about most natural languages – English, French, Hebrew, etc. –
that when we use modal terms in ordinary speech, we often do so in
logically misleading ways. Just see how natural it is to try to
formulate the preceding point [namely proposition (1)] in this
fashion:
(2) If α is true, then it is impossible for β to be false.
Or, in symbols:
(2a) α ⊃ ~◊~β
In ordinary speech, the latter sentence, (2), is natural and
idiomatic; the former sentence (1b) is unnatural and unidiomatic. But
– and this is the crucial point – the propositions expressed by
(1)-(1b) are not equivalent to the propositions expressed by sentences
(2)-(2a). The former set, that is (1)-(1b), are all true. The latter,
(2)-(2a)are false and commit the modal fallacy. The fallacy occurs in
its assigning the modality of impossibility, not to the relationship
between the truth of α and falsity of β as is done in (1)-(1b), but to
the falsity of β alone. Ordinary grammar beguiles us and misleads us.
It makes us believe that if α is true, then it is impossible for β to
be false. But it is possible for β to be false. β is a contingent
proposition. Recall the principle of the fixity of modal status. Even
if the falsity of β is guaranteed by the truth of some other
proposition [in this case α], β doesnot 'become' impossible: it
'remains' contingent, and thereby possible.
Whatever impossibility there is lies in jointly asserting α and
denying β. (See (1b) above.) The proposition "it is false that β" does
not 'become' impossible if one asserts α.[12]
a. The Modal Fallacy in Logical Determinism
Some persons have been deceived by the following (fallacious) argument
to the effect that there are no contingent propositions:
"(By the Law of Non-contradiction), if a proposition is true
(/false), then it cannot be false (/true). If a proposition cannot be
false (/true), then it is necessarily true (/false). Therefore if a
proposition is true (/false), it is necessarily true (/false). That
is, there are no contingent propositions. Every proposition is either
necessarily true or necessarily false. (If we could see the world from
God's viewpoint, we would see the necessity of everything. Contingency
is simply an artifact of ignorance. Contingency disappears with
complete knowledge.)"
The fallacy arises in the ambiguity of the first premise. If we
interpret it close to the English, we get:
P ⊃ ~◊~P
~◊~P ⊃ ☐P
∴ P ⊃ ☐ P
However, if we regard the English as misleading, as assigning a
necessity to what is simply nothing more than a necessary condition,
then we get instead as our premises:
~◊(P & ~P) [equivalently: ☐(P ⊃ P)]
~◊~P ⊃ ☐P
From these latter two premises, one cannot validly infer the conclusion:
P ⊃ ☐P.
In short, the argument to the effect that there are no contingent
propositions is unsound. Its very first premise commits the
modal fallacy.
The identical error occurs in the argument for logical determinism.
Recall (the expanded version of) Aristotle's sea battle:
Two warring admirals, A and B, are preparing their fleets for a
decisive sea battle tomorrow. The battle will be fought until one side
is victorious. But the 'logical laws (or principles)' of the excluded
middle (every proposition is either true or false) and of
noncontradiction (no proposition is both true and false), require that
one of the propositions, 'A wins' and 'it is false that A wins', is
true and the other is false. Suppose 'A wins' is (today) true. Then
whatever A does (or fails to do) today will make no difference: A must
win; similarly, whatever B does (or fails to do) today will make no
difference: the outcome is already settled, i.e. A must win. Or again,
suppose 'A wins' is (today) false. Then no matter what A does today
(or fails to do), it will make no difference: A must lose; similarly,
no matter what B does (or fails to do), it will make no difference:
the outcome is already settled, i.e. A must win. Thus, if every
proposition is either true or false (and not both), then planning, or
as Aristotle put it 'taking trouble', is futile. The future will be
what it will be, irrespective of our planning, intentions, etc.
If we let "A" stand for "Admiral A wins" and let "B" stand for
"Admiral B wins", the core of this argument can be stated in symbols
this way:
A or B [one or the other of these two propositions is true]
~◊(A & B) [it is not possible that both A and B are true]
∴ A ⊃ ☐A
A ⊃ ~◊~A } If A is true, then A must be true.
If A is true, then A cannot be false.
A ⊃ ☐~B
A ⊃ ~◊B } If A is true, then B must be
false.
If A is true, then B cannot be true.
B ⊃ ☐B
B ⊃ ~◊~B } If B is true, then B must be true.
If B is true, then B cannot be false.
B ⊃ ☐~A
B ⊃ ~◊A } If B is true, then A must be
false.
If B is true, then A cannot be true.
In this argument, by hypothesis, either A is true or B is true, and
since they cannot both be true, the second premise may be accepted as
true. But none of the conclusions is true. A is contingent, and B is
contingent. Yet the conclusions state that from the assumed truth of
either of (the two contingencies) A or B, it follows that A and B are
each either necessarily true or necessarily false. Each of these eight
conclusions violates the principle of the fixity of modal status.
What, then, are the conclusions one may draw validly from the
premises? These:
☐(A ⊃ ~B) or, equivalently, ~◊(A & B)
☐(B ⊃ ~A) or, equivalently, ~◊(B & A)
So long as we remain mindful of the fact that "~◊(P & Q)" is logically
equivalent to "☐(P ⊃ ~Q)" but is not equivalent to "P ⊃ ☐~Q", the
argument for logical determinism will be seen to be invalid.[13] Our
ordinary language treats "it is impossible for both P and Q to be
true" as if it were logically equivalent to "if P is true, then Q is
necessarily false". But the profound difference between these two
assertions is that the former preserves the principle of the fixity of
modal status, the latter violates that principle. The proposition,
"Admiral A wins", is contingent, and if true, then it 'remains' true.
Indeed this is a trivial logical truth:
(i) ☐(P ⊃ P) alternatively, ~◊(P & ~P)
The argument for logical determinism illicitly treats this logical
truth as if it were equivalent to the false proposition
(ii) P ⊃ ☐P alternatively, P ⊃ ~◊~P
If you do not let yourself be beguiled by the invalid 'move'
(inference) from (i) to (ii), the argument for logical determinism
collapses. The truth of a proposition concerning your future behavior
does not make that future behavior necessary. What you choose to do in
the future was, is, and will remain contingent, even if a proposition
describing that choice is timelessly true.
b. The Modal Fallacy in Epistemic Determinism
Let's recall Maimonides's argument:
… "Does God know or does He not know that a certain individual
will be good or bad? If thou sayest 'He knows', then it necessarily
follows that [that] man is compelled to act as God knew beforehand he
would act, otherwise God's knowledge would be imperfect."
We can symbolize the core of this argument, using "∴" for "it
necessarily follows"; and "☐" for "compelled"; and "D" for the
proposition describing what some particular person does tomorrow.
gKD
∴ ☐D
There seems to be (at least) one missing premise. [In the terminology
of logicians, the argument isenthymematic.] One tacit assumption of
this argument is the necessary truth, "it is not possible both for God
to know that D and for D to be false", or, in symbols, "~◊(gKD & ~D)".
So the argument becomes:
gKD
~◊(gKD & ~D)
∴ ☐D
But even with this repair, the argument remains invalid. The
conclusion does not follow from the two premises. To derive the
conclusion, a third premise is needed, and it is easy to see what it
is. Most persons, with hardly a moment's thought, virtually as a
reflex action, will tacitly assume that the second premise is
logically equivalent to:
gKD ⊃ ☐D
and will tacitly (/unconsciously) add this further premise, so as to
yield, finally:
gKD
~◊(gKD & ~D)
gKD ⊃ ☐D
∴ ☐D
But this third premise, we have seen above, is false; it commits the
modal fallacy. Without this premise, Maimonides' argument is invalid;
with it, the argument becomes valid but unsound (i.e. has a false and
essential premise [namely the third one]). Either way, the argument is
a logical botch.
Once the logical error is detected, and removed, the argument for
epistemic determinism simply collapses. If some future action/choice
is known prior to its occurrence, that event does not thereby become
"necessary", "compelled", "forced", or what have you. Inasmuch as its
description was, is, and will remain forever contingent, both it and
its negation remain possible. Of course only one of the two was, is,
and will remain true; while the other was, is, and will remain false.
But truth and falsity, per se, do not determine a proposition's
modality. Whether true or false, each of these propositions was, is,
and will remain possible. Knowing – whether by God or a human being –
some future event no more forces that event to occur than our learning
that dinosaurs lived in (what is now) South Dakota forced those
reptiles to take up residence there.
7. Residual concerns – Changing the past; Changing the future
It will sometimes happen that persons will painstakingly follow each
of the steps of the preceding arguments that expose the modal fallacy
in logical and epistemic determinism and still harbor lingering
worries that the truth or knowledge of future contingents precludes
the very possibility of free will
"Look", they might say, "if it is already true today (Monday) that
I will do Z tomorrow (Tuesday), then surely tomorrow, try as I might,
I will end up doing Z. Were I do something else instead, in effect not
do Z on Tuesday, then I would change, from true to false, the
truth-value that a proposition had on Monday. But that is impossible.
Thus, tomorrow, my considering the alternatives – my deliberating over
my course of action, my trying to make up my mind what I will choose,
my trying to exercise free will – is really just an illusion. Since I
can't change the past, and since it is already true before I act that
I will do Z, it clearly follows that I cannot exercise free will."
To tackle this last deterministic argument, we need to discuss two
matters: (1) what might be meant by the expressions "change the past"
and "change the future", and (2) whether changing the future involves
retroactively changing the truth-value of a proposition.
Changing the past, present, or future: The past is fixed. One cannot
undo what has happened (although one can, of course, try to mitigate
the consequences of wrongful acts – by apologizing, making amends,
etc.)
Not even an omnipotent God can 'undo' or 'redo' the past, for to do so
would per impossible actualize a self-contradiction (e.g. "x occurred
at such-and-such a time and x did not occur at such and such a time").
Jewish sages warn against 'prayer in vain' (where "in vain" does not
mean "futile" but "contemptuously" or "profanely" [as in the Third
Commandment, "Thou shalt not take the Lord's name in vain"]):
… to cry over the past is to utter a vain prayer. If a man's wife
is [already] pregnant and he says, "[God] grant that my wife bear a
male child", this is a vain prayer. If he is coming home from a
journey and he hears cries of distress in the town and says, "[God]
grant that this is not in my house", this is a vain prayer.[14]
Such prayers were regarded as blasphemous since they were taken to be
supplications to God that He change the past from the way it was. But
not even an omnipotent God can violate the logical principle of the
(law of) non-contradiction.
And yet, God-fearing persons frequently do utter such prayers. How
natural it is, for example, for Believers, when knowing that their
child was on board a particular ship, and learning that the ship has
met a terrible calamity and sunk – with some passengers being lost and
some others being rescued – to pray to God that their child is among
the survivors. Is there any way to rationalize such behavior and
render it non-blasphemous?
Modern modal logic again comes to the rescue. Remember, on traditional
accounts, God is (along with being all-good) omniscient and
omnipotent. God, being omniscient, will have known, since the
beginning of time, that the parents would pray (at such and such a
time) for the survival of their child. In particular, God would have
known at the time of the ship's sinking that the parents would pray
sometime later, and God could have chosen to answer those prayers in
advance of their being uttered. On this view, God is not changing the
past at all; God is making the past one particular way among the
infinite number of different ways it could have been. One must attend
to the modalities. Under this view, God does not change the past from
the way it was (which activity would be a violation of the principle
of non-contradiction), but rather God makes one possibility (the
child's surviving) actual, and makes another possibility (the child's
perishing) nonactual. There is no violation of the principle of
non-contradiction, and the parents' prayers are not blasphemous.
And it bears emphasizing that it is not God's knowing beforehand that
the parents would pray in a certain manner that 'brings it about'
('necessitates', 'forces') their praying that way. It is, quite the
contrary: it is the parents praying of their own free will that God
have saved their child from death that moves God to do (have done) as
he did.
Similar freedoms and constraints apply to the present. On pain of
inconsistency, one cannot change what is happening at this very
moment. In some circumstances, and in a certain sense, one can change
what is about to happen next (i.e. in the immediate future). But one
cannot change what is happening now, i.e. at this very moment.
What about the future? Most of us believe that we can, to a certain
extent, change (or affect) the future. But then we recall the proverb,
"Que sera, sera" ("What will be, will be"), and we begin to have
doubts. If the future will be what it is going to be, how can we
change it?
Not surprisingly, the response is: "It all depends on what you mean by
'change'".
"I cannot change the future – by anything I have done, am doing,
or will do – from what it is going to be. But I can change the future
from what it might have been. I may carefully consider the appearance
of my garden, and after a bit of thought, mulling over a few
alternatives, I decide to cut down the apple tree. By so doing, I
change the future from what it might have been. But I do not change it
from what it will be. Indeed, by my doing what I do, I contribute – in
a small measure – to making the future the very way it will
be."Similarly, I cannot change the present from the way it is. I can
only change the present from the way it might have been, from the way
it would have been were I not doing what I am doing right now. And
finally, I cannot change the past from the way it was. In the past, I
changed it from what it might have been, from what it would have been
had I not done what I did.
"We can change the world from what it might have been; but in
doing that we contribute to making the world the way it was, is, and
will be. We cannot – on pain of logical contradiction – change the
world from the way it was, is, or will be."[15]
Suppose that tomorrow, by the exercise of my free will, I wash the
family car. In doing so, I make the future just what it was to be. But
it was to be (that way rather than some other) just because I will
exercise my free will tomorrow. It is tomorrow's exercise of my free
will that makes it the way it will be.
In exercising my free will tomorrow (to wash the family car) have I
retroactively changed the past? Have I changed the truth-value of some
proposition from true to false and of some other proposition from
false to true?
Semantic relations are not causal relations: Again, the English
language confuses us. We say that what we willchoose to do tomorrow
'makes' some proposition true. And we might add, what I choose to do
tomorrow (namely wash the family car) 'makes' the car clean.
But these are two radically different senses of "makes". The first use
of "makes" refers to the semantic relation of "truth-conferring". My
washing the car tomorrow 'confers' truth on the proposition that on
such-and-such a day, I wash the family car. But an event's 'conferring
truth' on a proposition is not a causal relation. Causal relations
occur between two events (or occurrences, or states). The event of my
washing the car brings about the state (or the event that lasts
several days) of my car being clean.
The event of my washing the car tomorrow doesn't retroactively cause
the proposition that I wash the car tomorrow to become true, nor does
it change the truth-value of that proposition. The proposition that I
wash the car tomorrow (i.e. on such-and-such a date) simply describes
what happens tomorrow. If I do wash the car tomorrow, then that
proposition was, is, and forever will be, true. If I do not wash the
car tomorrow, then that same proposition was, is, and always will be
false.
Some persons find it easier to understand the concept of the semantic
relation of 'truth-making' if the example concerns a past event rather
than a future one. Consider the proposition (which is still being
debated by scientists) that the dinosaurs on earth perished as a
result of an impact of a huge meteor at Chicxulub, on the Yucatan
Peninsula in Mexico, about 65 million years ago. If there was such an
impact, and if it caused the demise of the dinosaurs, then the
proposition is true (or, more specifically, always was, is, and always
will be true). If, however, there was no such impact, or if there was
an impact but it didn't cause the death of the dinosaurs, then the
proposition always was, is, and forever will be false.
Every actual event has a timelessly true description. It is what
happens, i.e. what events occur – including those that are the free
choices of human beings – that 'accounts for' the truth of their
descriptions. The truth (today) of the proposition that John Wilkes
Booth assassinated Abraham Lincoln neither 'accounts for' nor 'caused'
that criminal act.
In the next few hours I will make any number of free choices. Tomorrow
there will be true propositions describing those choices. But none of
my choices today is 'forced' or 'caused by' my actual choices having
true descriptions tomorrow. And we can generalize:
In the next few hours you will exercise your free will and make
any number of free choices. Yesterday there were, today there are, and
tomorrow there will be, true propositions describing those choices.
But none of your choices today (whatever they are) is 'forced' or
'caused by' your actual choices having had a true description
yesterday, having a true description today, or continuing to have a
true description tomorrow.
8. Concluding Remarks
The argument (Logical Determinism) that a proposition's being true
prior to the occurrence of the event it describes logically precludes
free will ultimately rests on a modal fallacy. And the ancillary
argument that a proposition's being true prior to the occurrence of
the event it describes causes the future event to occur turns on a
confusion (i) of the truth-making (semantic) relation between an event
and its description with (ii) the causal relation between two events.
The argument (Epistemic Determinism) that a proposition's being known
prior to the occurrence of the event it describes logically precludes
free will, as in the case of logical determinism, ultimately rests on
a modal fallacy. And the arguments that it is impossible to know the
future are refuted by two facts. One is that we do in fact know a very
great deal about the future, indeed our managing to keep ourselves
alive from hour to hour, from day to day, depends to a very great
extent on such knowledge. Two is that the objection that we cannot
have knowledge of the future – because our beliefs about the future
'might' (turn out to) be false – turns on a mistaken account of the
role of 'the possibility of error' in a viable account of knowledge.
Beliefs about future actions, insofar as they are contingent, and – by
the very definition of "contingency" – are possibly false. But
"possibly false" does not mean "probably false", and possibly false
beliefs, so long as they are also actually true, canconstitute bona
fide knowledge of the future.
9. References and Further Reading
Complementary
William Lane Craig, The Only Wise God: The Compatibility of Divine
Foreknowledge and Human Freedom, (Grand Rapids, MI: Baker Book House),
1987. 157 pp.
William L. Rowe, Philosophy of Religion: An Introduction, 2nd edition
(Belmont, CA: Wadsworth Publishing Co.), 1993, esp. Chapter 11,
"Predestination, Divine Foreknowledge, and Human Freedom", pp.
141-154.
Dissenting
Nelson Pike has argued that if one adopts a particular notion of
omniscience [different from the one presupposed in this article],
God's omniscience does preclude the existence of human free will.
Alvin Plantinga responds to Pike, arguing that God's omniscience is
compatible with human free will. Finally, Pike tries to defend his
position against Plantinga. The three papers (listed in chronological
sequence) are:
Nelson Pike, "Divine Omniscience and Voluntary Action", in The
Philosophical Review, 74 (Jan. 1965) pp. 27-46. Reprinted as "God's
Foreknowledge and Human Free Will Are Incompatible", in Philosophy of
Religion: An Anthology, 2nd edition, edited by Louis P. Pojman,
(Belmont, CA: Wadsworth Publishing Co.), 1994, pp. 250-60.
Alvin Plantinga, "God's Foreknowledge and Human Free Will are
Compatible", in God, Freedom, and Evil, (New York: Harper & Row),
1974, pp. 66-72. Reprinted in Philosophy of Religion: An Anthology,
2nd edition, edited by Louis P. Pojman, (Belmont, CA: Wadsworth
Publishing Co.), 1994, pp. 261-4.
Nelson Pike, "Divine Foreknowledge, Human Freedom and Possible
Worlds", in The Philosophical Review, 86 (April 1977), pp. 209-216.
Supplementary: Causal Determinism
Throughout this paper we have examined two alleged threats to the
claim that human beings have free will, namely, the threat posed by
Logical Determinism and that posed by Epistemic Determinism. Early I
hived off the discussion of Causal Determinism. For many thinkers,
causal determinism poses a far greater threat to the existence of free
will than does either logical or epistemic determinism. Again, I
suggest as a starting point, the article, "Laws of Nature" in this
Encyclopedia.
Advanced
All three deterministic arguments are challenges to the thesis that
human beings have free will. And enormous efforts have been expended
over the last millennium, by countless philosophers and theologians,
to rebut these arguments. All these efforts have been, as it were,
defensive moves. And thus the question naturally arises: Is there, or
can there even be, arguments to the effect that free will does exist?
Is there any empirical evidence that human beings have the capacity to
exercise free choice? Is the claim demonstrable that we can, at least
on occasion, make free choices?
In his article, "An Essential Unpredictability in Human Behavior", in
Scientific Psychology: Principles and Approaches, edited by Ernest
Nagel and Benjamin Wolman, (New York: Basic Books), 1965, pp. 411-25,
Michael Scriven describes a thought-experiment which strongly supports
the claim that we have free will. (See esp. Section I., pp. 419-20.)
Most persons will need to read this paper several times, and without a
dismissive attitude, to plumb its cogency and depth. The paper is
undeniably tough going, but, in the end, worth the effort needed to
grasp its insights.
10. Notes
1. The Eight Chapters of Maimonides on Ethics (Semonah Perak.im),
edited, annotated, and translated with an Introduction by Joseph I.
Gorfinkle, pp. 99-100. (New York: AMS Press), 1966. [ Return ]
2. Although contemporary (twentieth- and twenty-first-century)
secular philosophers continue the historical tradition of talking
about God as a (/the) omniscient being, one should not thereby infer
that these philosophers are assuming that God exists. For contemporary
secular philosophers, "God" may be regarded as shorthand for
"omniscient being". Their interest is in the consequences of positing
an omniscient being, not in promoting a belief that such a being
exists. The latter is a quite different matter, not touched upon in
this article. [ Return ]
3. The term "proposition" is being used in a technical sense. It
refers, not to sentences, but to the non-linguistic statements that
can be expressed by indicative (or declarative) sentences. For
example, if an English-speaking person were to utter the sentence,
"Saturn is the sixth planet from the Sun", and a French-speaking
person were to utter the sentence, "Saturne est la sixième planète la
plus éloignée du soleil", both would have expressed the same
proposition – two different sentences, one proposition. However, were
one person, let's say Efrem, to utter the sentence, "I can see
Saturn", and someone else, let's say Diane, were to utter the
sentence, "I can see Saturn", this would be a case of these persons
uttering the same sentence, but expressing two different propositions,
one about Efrem, the other about Diane. For more on the distinction
between sentences and propositions see "What sorts of things are true
(or false)?" in this Encyclopedia. [ Return ]
4. Carl Hempel, "The Function of General Laws in History", in The
Journal of Philosophy, 39, pp.35-48 (1942). Reprinted in Aspects of
Scientific Explanation, (NY: The Free Press), 1965,pp. 231-243. [
Return ]
5. This second condition is stated loosely. Indeed ever since 1963,
when Edmund L. Gettier published his paper, "Is Knowledge Justified
True Belief?", in Analysis 23, pp. 121-123, a number of philosophers
have tried their hands at 'tightening' the conditions that are
necessary for knowledge. However, for our purposes, we need not settle
on whether these conditions are sufficient for knowledge. For the
present discussion, we need only insist upon the first condition
(namely P is true), a condition that has been little challenged in
late-twentieth- and early twenty-first-century theory of knowledge. [
Return ]
6. In the case of God, truth is not only a necessary condition for
His knowledge, it is also sufficient. If we let "g" stand for "God",
"K" for "knows", then gKP implies P, and P implies gKP. [ Return ]
7. Aristotle's Categories and De Interpretatione, translated with
notes by J.L. Ackrill (Oxford: Clarendon Press), 1963, Chapter 9 (pp.
50-53). [ Return ]
8. Judith Jarvis Thomson, "The time of a killing", Journal of
Philosophy, 68 (1971), pp. 115-32. [ Return ]
9. Glorious Eclipses: Their Past, Present and Future, by Serge
Brunier and Jean-Pierre Luminet, translated by Storm Dunlop
(Cambridge: Cambridge University Press), 2000, pp.154-5. ISBN 0 521
79148 0.See also NASA's "Eclipse Home Page". [ Return ]
10. René Descartes, Meditations on First Philosophy (1641), p. 1.
Re-written (2004) by Jonathan Bennett, for readability by students in
the 21st century, from the translation by John Cottingham (Cambridge
University Press), 1996. [ Return ]
11. Just as an exercise, try to state the following formula solely
in English prose:
x = [√(y2 + z√w)] / [2.7w (a3 + log(y - 0.5z))]
For further illustrations of the difficulty on occasion of
expressing fine logical points in ordinary prose, see Ernest Nagel's
celebrated "Symbolic Notation, Haddocks' Eyes and the Dog-Walking
Ordinance" (esp. the latter section), in The World of Mathematics,
vol. 3, edited by James R. Newman (NY: Simon and Schuster), 1956, pp.
1878-1900. (Reissued by Dover Publications. ISBN: 0486432688) [ Return
]
12. The modal fallacy is hardly the only case of human beings'
susceptibility to logical error. Another logical error, this one drawn
from mathematics, which – like the modal fallacy – took centuries to
be corrected, has to do with the number of numbers. If one were to ask
most persons, "Are there more even and odd positive integers (1, 2, 3,
4, …) than there are even positive integers (2, 4, 6, 8, …) alone?",
one would likely get as an answer, "Yes, of course. There are twice as
many even and odd positive integers together as there are even
positive integers alone." But contrary to our untutored intuitions,
this is the wrong answer. It turns out, as was discovered and proved
in the 19th century (by Georg Cantor [1845-1918]), there are exactly
as many even positive integers as there are even and odd together. The
two classes, that of all the positive integers and that of the even
positive integers are said to be "equinumerous", that is, both classes
contain the same number (cardinality) of members, namely an infinite
number. That there are as many even positive integers as there are
positive integers can be demonstrated by the fact that the members of
the two classes can be uniquely 'paired off', or putting the point in
more technical jargon, the members of the two classes can be put into
a "one-to-one correspondence":
1 2 3 4 . . . .
| | | | | | etc.
2 4 6 8 . . . .
Every positive integer has a unique double; and every even
positive integer has a unique half which is also an integer. Clearly,
there are instances when some of our untutored, deeply ingrained,
logical (and mathematical) 'intuitions' need to be reformed.[ Return ]
13. The non-equivalence of "~◊(P & Q)" and "(P ⊃ ☐~Q)" has been
explained and illustrated in this article. For techniques, within
modal logic, to prove that these two expressions are not equivalent,
see, for example, Possible Worlds, by Raymond Bradley and Norman
Swartz (Indianapolis: Hackett Publishing Co.), 1979, esp. pp. 350-65.
[ Return ]
14. The Babylonian Talmud, Tractate Berakoth, Chapter IX. Translated
by Isidore Epstein, 1948 (reprinted 1978), (London: The Soncino Press
[Oxford]). pp. 327-8. [ Return ]
15. Norman Swartz, Beyond Experience, 2nd edition (2001) pp.
226-227. [ Return ]
No comments:
Post a Comment