philosophers in the history of Western philosophy. His contributions
to metaphysics, epistemology, ethics, and aesthetics have had a
profound impact on almost every philosophical movement that followed
him. This portion of the Encyclopedia entry will focus on his
metaphysics and epistemology in one of his most important works, The
Critique of Pure Reason. A large part of Kant's work addresses the
question "What can we know?" The answer, if it can be stated simply,
is that our knowledge is constrained to mathematics and the science of
the natural, empirical world. It is impossible, Kant argues, to extend
knowledge to the supersensible realm of speculative metaphysics. The
reason that knowledge has these constraints, Kant argues, is that the
mind plays an active role in constituting the features of experience
and limiting the mind's access to the empirical realm of space and
time.
1. Historical Background to Kant
In order to understand Kant's position, we must understand the
philosophical background that he was reacting to. First, this article
presents a brief overview of his predecessor's positions with a brief
statement of Kant's objections, then I will return to a more detailed
exposition of Kant's arguments. There are two major historical
movements in the early modern period of philosophy that had a
significant impact on Kant: Empiricism and Rationalism. Kant argues
that both the method and the content of these philosophers' arguments
contain serious flaws. A central epistemological problem for
philosophers in both movements was determining how we can escape from
within the confines of the human mind and the immediately knowable
content of our own thoughts to acquire knowledge of the world outside
of us. The Empiricists sought to accomplish this through the senses
and a posteriori reasoning. The Rationalists attempted to use a priori
reasoning to build the necessary bridge. A posteriori reasoning
depends upon experience or contingent events in the world to provide
us with information. That "Bill Clinton was president of the United
States in 1999," for example, is something that I can know only
through experience; I cannot determine this to be true through an
analysis of the concepts of "president" or "Bill Clinton." A priori
reasoning, in contrast, does not depend upon experience to inform it.
The concept "bachelor" logically entails the ideas of an unmarried,
adult, human male without my needing to conduct a survey of bachelors
and men who are unmarried. Kant believed that this twofold distinction
in kinds of knowledge was inadequate to the task of understanding
metaphysics for reasons we will discuss in a moment.
a. Empiricism
Empiricists, such as Locke, Berkeley, and Hume, argued that human
knowledge originates in our sensations. Locke, for instance, was a
representative realist about the external world and placed great
confidence in the ability of the senses to inform us of the properties
that empirical objects really have in themselves. Locke had also
argued that the mind is a blank slate, or a tabula rasa, that becomes
populated with ideas by its interactions with the world. Experience
teaches us everything, including concepts of relationship, identity,
causation, and so on. Kant argues that the blank slate model of the
mind is insufficient to explain the beliefs about objects that we
have; some components of our beliefs must be brought by the mind to
experience.
Berkeley's strict phenomenalism, in contrast to Locke, raised
questions about the inference from the character of our sensations to
conclusions about the real properties of mind-independent objects.
Since the human mind is strictly limited to the senses for its input,
Berkeley argued, it has no independent means by which to verify the
accuracy of the match between sensations and the properties that
objects possess in themselves. In fact, Berkeley rejected the very
idea of mind-independent objects on the grounds that a mind is, by its
nature, incapable of possessing an idea of such a thing. Hence, in
Kant's terms, Berkeley was a material idealist. To the material
idealist, knowledge of material objects is ideal or unachievable, not
real. For Berkeley, mind-independent material objects are impossible
and unknowable. In our sense experience we only have access to our
mental representations, not to objects themselves. Berkeley argues
that our judgments about objects are really judgments about these
mental representations alone, not the substance that gives rise to
them. In the Refutation of Material Idealism, Kant argues that
material idealism is actually incompatible with a position that
Berkeley held, namely that we are capable of making judgments about
our experience.
David Hume pursued Berkeley's empirical line of inquiry even further,
calling into question even more of our common sense beliefs about the
source and support of our sense perceptions. Hume maintains that we
cannot provide a priori or a posteriori justifications for a number of
our beliefs like, "Objects and subjects persist identically over
time," or "Every event must have a cause." In Hume's hands, it becomes
clear that empiricism cannot give us an epistemological justification
for the claims about objects, subjects, and causes that we took to be
most obvious and certain about the world.
Kant expresses deep dissatisfaction with the idealistic and seemingly
skeptical results of the empirical lines of inquiry. In each case,
Kant gives a number of arguments to show that Locke's, Berkeley's, and
Hume's empiricist positions are untenable because they necessarily
presupposes the very claims they set out to disprove. In fact, any
coherent account of how we perform even the most rudimentary mental
acts of self-awareness and making judgments about objects must
presuppose these claims, Kant argues. Hence, while Kant is sympathetic
with many parts of empiricism, ultimately it cannot be a satisfactory
account of our experience of the world.
b. Rationalism
The Rationalists, principally Descartes, Spinoza, and Leibniz,
approached the problems of human knowledge from another angle. They
hoped to escape the epistemological confines of the mind by
constructing knowledge of the external world, the self, the soul, God,
ethics, and science out of the simplest, indubitable ideas possessed
innately by the mind. Leibniz in particular, thought that the world
was knowable a priori, through an analysis of ideas and derivations
done through logic. Supersensible knowledge, the Rationalists argued,
can be achieved by means of reason. Descartes believed that certain
truths, that "if I am thinking, I exist," for example, are
invulnerable to the most pernicious skepticism. Armed with the
knowledge of his own existence, Descartes hoped to build a foundation
for all knowledge.
Kant's Refutation of Material Idealism works against Descartes'
project as well as Berkeley's. Descartes believed that he could infer
the existence of objects in space outside of him based on his
awareness of his own existence coupled with an argument that God
exists and is not deceiving him about the evidence of his senses. Kant
argues in the Refutation chapter that knowledge of external objects
cannot be inferential. Rather, the capacity to be aware of one's own
existence in Descartes' famous cogito argument already presupposes
that existence of objects in space and time outside of me.
Kant had also come to doubt the claims of the Rationalists because of
what he called Antinomies, or contradictory, but validly proven pairs
of claims that reason is compelled toward. From the basic principles
that the Rationalists held, it is possible, Kant argues, to prove
conflicting claims like, "The world has a beginning in time and is
limited as regards space," and "The world has no beginning, and no
limits in space." (A 426/B 454) Kant claims that antinomies like this
one reveal fundamental methodological and metaphysical mistakes in the
rationalist project. The contradictory claims could both be proven
because they both shared the mistaken metaphysical assumption that we
can have knowledge of things as they are in themselves, independent of
the conditions of our experience of them.
The Antinomies can be resolved, Kant argues, if we understand the
proper function and domain of the various faculties that contribute to
produce knowledge. We must recognize that we cannot know things as
they are in themselves and that our knowledge is subject to the
conditions of our experience. The Rationalist project was doomed to
failure because it did not take note of the contribution that our
faculty of reason makes to our experience of objects. Their a priori
analysis of our ideas could inform us about the content of our ideas,
but it could not give a coherent demonstration of metaphysical truths
about the external world, the self, the soul, God, and so on.
2. Kant's Answers to his Predecessors
Kant's answer to the problems generated by the two traditions
mentioned above changed the face of philosophy. First, Kant argued
that that old division between a priori truths and a posteriori truths
employed by both camps was insufficient to describe the sort of
metaphysical claims that were under dispute. An analysis of knowledge
also requires a distinction between synthetic and analytic truths. In
an analytic claim, the predicate is contained within the subject. In
the claim, "Every body occupies space," the property of occupying
space is revealed in an analysis of what it means to be a body. The
subject of a synthetic claim, however, does not contain the predicate.
In, "This tree is 120 feet tall," the concepts are synthesized or
brought together to form a new claim that is not contained in any of
the individual concepts. The Empiricists had not been able to prove
synthetic a priori claims like "Every event must have a cause,"
because they had conflated "synthetic" and "a posteriori" as well as
"analytic" and "a priori." Then they had assumed that the two
resulting categories were exhaustive. A synthetic a priori claim, Kant
argues, is one that must be true without appealing to experience, yet
the predicate is not logically contained within the subject, so it is
no surprise that the Empiricists failed to produce the sought after
justification. The Rationalists had similarly conflated the four terms
and mistakenly proceeded as if claims like, "The self is a simple
substance," could be proven analytically and a priori.
Synthetic a priori claims, Kant argues, demand an entirely different
kind of proof than those required for analytic, a priori claims or
synthetic, a posteriori claims. Indications for how to proceed, Kant
says, can be found in the examples of synthetic a priori claims in
natural science and mathematics, specifically geometry. Claims like
Newton's, "the quantity of matter is always preserved," and the
geometer's claim, "the angles of a triangle always add up to 180
degrees" are known a priori, but they cannot be known merely from an
analysis of the concepts of matter or triangle. We must "go outside
and beyond the concept. . . joining to it a priori in thought
something which I have not thought in it." (B 18) A synthetic a priori
claim constructs upon and adds to what is contained analytically in a
concept without appealing to experience. So if we are to solve the
problems generated by Empiricism and Rationalism, the central question
of metaphysics in the Critique of Pure Reason reduces to "How are
synthetic a priori judgments possible?" (19) (All references to The
Critique of Pure Reason will be to the A (1781) and B(1787) edition
pages in Werner Pluhar's translation. Indianapolis: Hackett, 1996.) If
we can answer that question, then we can determine the possibility,
legitimacy, and range of all metaphysical claims.
3. Kant's Copernican Revolution: Mind Making Nature
Kant's answer to the question is complicated, but his conclusion is
that a number of synthetic a priori claims, like those from geometry
and the natural sciences, are true because of the structure of the
mind that knows them. "Every event must have a cause" cannot be proven
by experience, but experience is impossible without it because it
describes the way the mind must necessarily order its representations.
We can understand Kant's argument again by considering his
predecessors. According to the Rationalist and Empiricist traditions,
the mind is passive either because it finds itself possessing innate,
well-formed ideas ready for analysis, or because it receives ideas of
objects into a kind of empty theater, or blank slate. Kant's crucial
insight here is to argue that experience of a world as we have it is
only possible if the mind provides a systematic structuring of its
representations. This structuring is below the level of, or logically
prior to, the mental representations that the Empiricists and
Rationalists analyzed. Their epistemological and metaphysical theories
could not adequately explain the sort of judgments or experience we
have because they only considered the results of the mind's
interaction with the world, not the nature of the mind's contribution.
Kant's methodological innovation was to employ what he calls a
transcendental argument to prove synthetic a priori claims. Typically,
a transcendental argument attempts to prove a conclusion about the
necessary structure of knowledge on the basis of an incontrovertible
mental act. Kant argues in the Refutation of Material Idealism that
"There are objects that exist in space and time outside of me," (B
274) which cannot be proven by a priori or a posteriori methods, is a
necessary condition of the possibility of being aware of one's own
existence. It would not be possible to be aware of myself as existing,
he says, without presupposing the existing of something permanent
outside of me to distinguish myself from. I am aware of myself as
existing. Therefore, there is something permanent outside of me.
This argument is one of many transcendental arguments that Kant gives
that focuses on the contribution that the mind itself makes to its
experience. These arguments lead Kant to conclude that the
Empiricists' assertion that experience is the source of all our ideas.
It must be the mind's structuring, Kant argues, that makes experience
possible. If there are features of experience that the mind brings to
objects rather than given to the mind by objects, that would explain
why they are indispensable to experience but unsubstantiated in it.
And that would explain why we can give a transcendental argument for
the necessity of these features. Kant thought that Berkeley and Hume
identified at least part of the mind's a priori contribution to
experience with the list of claims that they said were unsubstantiated
on empirical grounds: "Every event must have a cause," "There are
mind-independent objects that persist over time," and "Identical
subjects persist over time." The empiricist project must be incomplete
since these claims are necessarily presupposed in our judgments, a
point Berkeley and Hume failed to see. So, Kant argues that a
philosophical investigation into the nature of the external world must
be as much an inquiry into the features and activity of the mind that
knows it.
The idea that the mind plays an active role in structuring reality is
so familiar to us now that it is difficult for us to see what a
pivotal insight this was for Kant. He was well aware of the idea's
power to overturn the philosophical worldviews of his contemporaries
and predecessors, however. He even somewhat immodestly likens his
situation to that of Copernicus in revolutionizing our worldview. On
the Lockean view, mental content is given to the mind by the objects
in the world. Their properties migrate into the mind, revealing the
true nature of objects. Kant says, "Thus far it has been assumed that
all our cognition must conform to objects" (B xvi). But that approach
cannot explain why some claims like, "every event must have a cause,"
are a priori true. Similarly, Copernicus recognized that the movement
of the stars cannot be explained by making them revolve around the
observer; it is the observer that must be revolving. Analogously, Kant
argued that we must reformulate the way we think about our
relationship to objects. It is the mind itself which gives objects at
least some of their characteristics because they must conform to its
structure and conceptual capacities. Thus, the mind's active role in
helping to create a world that is experiencable must put it at the
center of our philosophical investigations. The appropriate starting
place for any philosophical inquiry into knowledge, Kant decides, is
with the mind that can have that knowledge.
Kant's critical turn toward the mind of the knower is ambitious and
challenging. Kant has rejected the dogmatic metaphysics of the
Rationalists that promises supersensible knowledge. And he has argued
that Empiricism faces serious limitations. His transcendental method
will allow him to analyze the metaphysical requirements of the
empirical method without venturing into speculative and ungrounded
metaphysics. In this context, determining the "transcendental"
components of knowledge means determining, "all knowledge which is
occupied not so much with objects as with the mode of our knowledge of
objects in so far as this mode of knowledge is to be possible a
priori." (A 12/B 25)
The project of the Critique of Pure Reason is also challenging because
in the analysis of the mind's transcendental contributions to
experience we must employ the mind, the only tool we have, to
investigate the mind. We must use the faculties of knowledge to
determine the limits of knowledge, so Kant's Critique of Pure Reason
is both a critique that takes pure reason as its subject matter, and a
critique that is conducted by pure reason.
Kant's argument that the mind makes an a priori contribution to
experiences should not be mistaken for an argument like the
Rationalists' that the mind possesses innate ideas like, "God is a
perfect being." Kant rejects the claim that there are complete
propositions like this one etched on the fabric of the mind. He argues
that the mind provides a formal structuring that allows for the
conjoining of concepts into judgments, but that structuring itself has
no content. The mind is devoid of content until interaction with the
world actuates these formal constraints. The mind possesses a priori
templates for judgments, not a priori judgments.
4. Kant's Transcendental Idealism
With Kant's claim that the mind of the knower makes an active
contribution to experience of objects before us, we are in a better
position to understand Kant's arguments are designed to show the
limitations of our knowledge. The Rationalists believed that we could
possess metaphysical knowledge about God, souls, substance, and so;
they believed such knowledge was transcendentally real. Kant argues,
however, that we cannot have knowledge of the realm beyond the
empirical. That is, transcendental knowledge is ideal, not real, for
minds like ours. Kant identifies two a priori sources of these
constraints. The mind has a receptive capacity, or the transcendental
idealism.sensibility, and the mind possesses a conceptual capacity, or
the understanding.
In the Transcendental Aesthetic section of the Critique, Kant argues
that sensibility is the understanding's means of accessing objects.
The reason synthetic a priori judgments are possible in geometry, Kant
argues, is that space is an a priori form of sensibility. That is, we
can know the claims of geometry with a priori certainty (which we do)
only if experiencing objects in space is the necessary mode of our
experience. Kant also argues that we cannot experience objects without
being able to represent them spatially. It is impossible to grasp an
object as an object unless we delineate the region of space it
occupies. Without a spatial representation, our sensations are
undifferentiated and we cannot ascribe properties to particular
objects. Time, Kant argues, is also necessary as a form or condition
of our intuitions of objects. The idea of time itself cannot be
gathered from experience because succession and simultaneity of
objects, the phenomena that would indicate the passage of time, would
be impossible to represent if we did not already possess the capacity
to represent objects in time.
Another way to understand Kant's point here is that it is impossible
for us to have any experience of objects that are not in time and
space. Furthermore, space and time themselves cannot be perceived
directly, so they must be the form by which experience of objects is
had. A consciousness that apprehends objects directly, as they are in
themselves and not by means of space and time, is possible–God, Kant
says, has a purely intuitive consciousness–but our apprehension of
objects is always mediated by the conditions of sensibility. Any
discursive or concept using consciousness (A 230/B 283) like ours must
apprehend objects as occupying a region of space and persisting for
some duration of time.
Subjecting sensations to the a priori conditions of space and time is
not sufficient to make judging objects possible. Kant argues that the
understanding must provide the concepts, which are rules for
identifying what is common or universal in different
representations.(A 106) He says, "without sensibility no object would
be given to us; and without understanding no object would be thought.
Thoughts without content are empty; intuitions without concepts are
blind." (B 75) Locke's mistake was believing that our sensible
apprehensions of objects are thinkable and reveal the properties of
the objects themselves. In the Analytic of Concepts section of the
Critique, Kant argues that in order to think about the input from
sensibility, sensations must conform to the conceptual structure that
the mind has available to it. By applying concepts, the understanding
takes the particulars that are given in sensation and identifies what
is common and general about them. A concept of "shelter" for instance,
allows me to identify what is common in particular representations of
a house, a tent, and a cave.
The empiricist might object at this point by insisting that such
concepts do arise from experience, raising questions about Kant's
claim that the mind brings an a priori conceptual structure to the
world. Indeed, concepts like "shelter" do arise partly from
experience. But Kant raises a more fundamental issue. An empirical
derivation is not sufficient to explain all of our concepts. As we
have seen, Hume argued, and Kant accepts, that we cannot empirically
derive our concepts of causation, substance, self, identity, and so
forth. What Hume had failed to see, Kant argues, is that even the
possibility of making judgments about objects, to which Hume would
assent, presupposes the possession of these fundamental concepts. Hume
had argued for a sort of associationism to explain how we arrive at
causal beliefs. My idea of a moving cue ball, becomes associated with
my idea of the eight ball that is struck and falls into the pocket.
Under the right circumstances, repeated impressions of the second
following the first produces a belief in me that the first causes the
second.
The problem that Kant points out is that a Humean association of ideas
already presupposes that we can conceive of identical, persistent
objects that have regular, predictable, causal behavior. And being
able to conceive of objects in this rich sense presupposes that the
mind makes several a priori contributions. I must be able to separate
the objects from each other in my sensations, and from my sensations
of myself. I must be able to attribute properties to the objects. I
must be able to conceive of an external world with its own course of
events that is separate from the stream of perceptions in my
consciousness. These components of experience cannot be found in
experience because they constitute it. The mind's a priori conceptual
contribution to experience can be enumerated by a special set of
concepts that make all other empirical concepts and judgments
possible. These concepts cannot be experienced directly; they are only
manifest as the form which particular judgments of objects take. Kant
believes that formal logic has already revealed what the fundamental
categories of thought are. The special set of concepts is Kant's Table
of Categories, which are taken mostly from Aristotle with a few
revisions:
Of Quantity
Unity
Plurality
Totality
Of Quality Of Relation
Reality Inherence and Subsistence
Negation Causality and Dependence
Limitation Community
Of Modality
Possibility-Impossibility
Existence-Nonexistence
Necessity-Contingency
While Kant does not give a formal derivation of it, he believes that
this is the complete and necessary list of the a priori contributions
that the understanding brings to its judgments of the world. Every
judgment that the understanding can make must fall under the table of
categories. And subsuming spatiotemporal sensations under the formal
structure of the categories makes judgments, and ultimately knowledge,
of empirical objects possible.
Since objects can only be experienced spatiotemporally, the only
application of concepts that yields knowledge is to the empirical,
spatiotemporal world. Beyond that realm, there can be no sensations of
objects for the understanding to judge, rightly or wrongly. Since
intuitions of the physical world are lacking when we speculate about
what lies beyond, metaphysical knowledge, or knowledge of the world
outside the physical, is impossible. Claiming to have knowledge from
the application of concepts beyond the bounds of sensation results in
the empty and illusory transcendent metaphysics of Rationalism that
Kant reacts against.
It should be pointed out, however, that Kant is not endorsing an
idealism about objects like Berkeley's. That is, Kant does not believe
that material objects are unknowable or impossible. While Kant is a
transcendental idealist–he believes the nature of objects as they are
in themselves is unknowable to us–knowledge of appearances is
nevertheless possible. As noted above, in The Refutation of Material
Idealism, Kant argues that the ordinary self-consciousness that
Berkeley and Descartes would grant implies "the existence of objects
in space outside me." (B 275) Consciousness of myself would not be
possible if I were not able to make determinant judgments about
objects that exist outside of me and have states that are independent
of the of my inner experience. Another way to put the point is to say
that the fact that the mind of the knower makes the a priori
contribution does not mean that space and time or the categories are
mere figments of the imagination. Kant is an empirical realist about
the world we experience; we can know objects as they appear to us. He
gives a robust defense of science and the study of the natural world
from his argument about the mind's role in making nature. All
discursive, rational beings must conceive of the physical world as
spatially and temporally unified, he argues. And the table of
categories is derived from the most basic, universal forms of logical
inference, Kant believes. Therefore, it must be shared by all rational
beings. So those beings also share judgments of an intersubjective,
unified, public realm of empirical objects. Hence, objective knowledge
of the scientific or natural world is possible. Indeed, Kant believes
that the examples of Newton and Galileo show it is actual. So
Berkeley's claims that we do not know objects outside of us and that
such knowledge is impossible are both mistaken.
In conjunction with his analysis of the possibility of knowing
empirical objects, Kant gives an analysis of the knowing subject that
has sometimes been called his transcendental psychology. Much of
Kant's argument can be seen as subjective, not because of variations
from mind to mind, but because the source of necessity and
universality is in the mind of the knowing subject, not in objects
themselves. Kant draws several conclusions about what is necessarily
true of any consciousness that employs the faculties of sensibility
and understanding to produce empirical judgments. As we have seen, a
mind that employs concepts must have a receptive faculty that provides
the content of judgments. Space and time are the necessary forms of
apprehension for the receptive faculty. The mind that has experience
must also have a faculty of combination or synthesis, the imagination
for Kant, that apprehends the data of sense, reproduces it for the
understanding, and recognizes their features according to the
conceptual framework provided by the categories. The mind must also
have a faculty of understanding that provides empirical concepts and
the categories for judgment. The various faculties that make judgment
possible must be unified into one mind. And it must be identical over
time if it is going to apply its concepts to objects over time. Kant
here addresses Hume's famous assertion that introspection reveals
nothing more than a bundle of sensations that we group together and
call the self. Judgments would not be possible, Kant maintains, if the
mind that senses is not the same as the mind that possesses the forms
of sensibility. And that mind must be the same as the mind that
employs the table of categories, that contributes empirical concepts
to judgment, and that synthesizes the whole into knowledge of a
unified, empirical world. So the fact that we can empirically judge
proves, contra Hume, that the mind cannot be a mere bundle of
disparate introspected sensations. In his works on ethics Kant will
also argue that this mind is the source of spontaneous, free, and
moral action. Kant believes that all the threads of his transcendental
philosophy come together in this "highest point" which he calls the
transcendental unity of apperception.
5. Kant's Analytic of Principles
We have seen the progressive stages of Kant's analysis of the
faculties of the mind which reveals the transcendental structuring of
experience performed by these faculties. First, in his analysis of
sensibility, he argues for the necessarily spatiotemporal character of
sensation. Then Kant analyzes the understanding, the faculty that
applies concepts to sensory experience. He concludes that the
categories provide a necessary, foundational template for our concepts
to map onto our experience. In addition to providing these
transcendental concepts, the understanding also is the source of
ordinary empirical concepts that make judgments about objects
possible. The understanding provides concepts as the rules for
identifying the properties in our representations.
Kant's next concern is with the faculty of judgment, "If understanding
as such is explicated as our power of rules, then the power of
judgment is the ability to subsume under rules, i.e., to distinguish
whether something does or does not fall under a given rule." (A 132/B
172). The next stage in Kant's project will be to analyze the formal
or transcendental features of experience that enable judgment, if
there are any such features besides what the previous stages have
identified. The cognitive power of judgment does have a transcendental
structure. Kant argues that there are a number of principles that must
necessarily be true of experience in order for judgment to be
possible. Kant's analysis of judgment and the arguments for these
principles are contained in his Analytic of Principles.
Within the Analytic, Kant first addresses the challenge of subsuming
particular sensations under general categories in the Schematism
section. Transcendental schemata, Kant argues, allow us to identify
the homogeneous features picked out by concepts from the heterogeneous
content of our sensations. Judgment is only possible if the mind can
recognize the components in the diverse and disorganized data of sense
that make those sensations an instance of a concept or concepts. A
schema makes it possible, for instance, to subsume the concrete and
particular sensations of an Airedale, a Chihuahua, and a Labrador all
under the more abstract concept "dog."
The full extent of Kant's Copernican revolution becomes even more
clear in the rest of the Analytic of Principles. That is, the role of
the mind in making nature is not limited to space, time, and the
categories. In the Analytic of Principles, Kant argues that even the
necessary conformity of objects to natural law arises from the mind.
Thus far, Kant's transcendental method has permitted him to reveal the
a priori components of sensations, the a priori concepts. In the
sections titled the Axioms, Anticipations, Analogies, and Postulates,
he argues that there are a priori judgments that must necessarily
govern all appearances of objects. These judgments are a function of
the table of categories' role in determining all possible judgments,
so the four sections map onto the four headings of that table. I
include all of the a priori judgments, or principles, here to
illustrate the earlier claims about Kant's empirical realism, and to
show the intimate relationship Kant saw between his project and that
of the natural sciences:
Axioms of Intuition
All intuitions are extensive magnitudes.
Anticipations of Perception Analogies of Experience
In all appearances the real that is an object of sensation has
intensive magnitude, i.e., a degree. In all variations by
appearances substance is permanent, and its quantum in nature is
neither increased nor decreased.
All changes occur according to the law of the connection of cause and effect.
All substances, insofar as they can be perceived in space as
simultaneous, are in thoroughgoing interaction.
Postulates of Empirical Thought
What agrees (in terms of intuition and concepts) with the formal
conditions of experience is possible.
What coheres with the material conditions of experience (with
sensation) is actual.
That whose coherence with the actual is determined according to
universal conditions of experience is necessary (exists necessarily)
6. Kant's Dialectic
The discussion of Kant's metaphysics and epistemology so far
(including the Analytic of Principles)has been confined primarily to
the section of the Critique of Pure Reason that Kant calls the
Transcendental Analytic. The purpose of the Analytic, we are told, is
"the rarely attempted dissection of the power of the understanding
itself." (A 65/B 90). Kant's project has been to develop the full
argument for his theory about the mind's contribution to knowledge of
the world. Once that theory is in place, we are in a position to see
the errors that are caused by transgressions of the boundaries to
knowledge established by Kant's transcendental idealism and empirical
realism. Kant calls judgments that pretend to have knowledge beyond
these boundaries and that even require us to tear down the limits that
he has placed on knowledge, transcendent judgments. The Transcendental
Dialectic section of the book is devoted to uncovering the illusion of
knowledge created by transcendent judgments and explaining why the
temptation to believe them persists. Kant argues that the proper
functioning of the faculties of sensibility and the understanding
combine to draw reason, or the cognitive power of inference,
inexorably into mistakes. The faculty of reason naturally seeks the
highest ground of unconditional unity. It seeks to unify and subsume
all particular experiences under higher and higher principles of
knowledge. But sensibility cannot by its nature provide the intuitions
that would make knowledge of the highest principles and of things as
they are in themselves possible. Nevertheless, reason, in its function
as the faculty of inference, inevitably draws conclusions about what
lies beyond the boundaries of sensibility. The unfolding of this
conflict between the faculties reveals more about the mind's
relationship to the world it seeks to know and the possibility of a
science of metaphysics.
Kant believes that Aristotle's logic of the syllogism captures the
logic employed by reason. The resulting mistakes from the inevitable
conflict between sensibility and reason reflect the logic of
Aristotle's syllogism. Corresponding to the three basic kinds of
syllogism are three dialectic mistakes or illusions of transcendent
knowledge that cannot be real. Kant's discussion of these three
classes of mistakes are contained in the Paralogisms, the Antinomies,
and the Ideals of Reason. The Dialectic explains the illusions of
reason in these sections. But since the illusions arise from the
structure of our faculties, they will not cease to have their
influence on our minds any more than we can prevent the moon from
seeming larger when it is on the horizon than when it is overhead. (A
297/B 354).
In the Paralogisms, Kant argues that a failure to recognize the
difference between appearances and things in themselves, particularly
in the case of the introspected self, lead us into transcendent error.
Kant argues against several conclusions encouraged by Descartes and
the rational psychologists, who believed they could build human
knowledge from the "I think" of the cogito argument. From the "I
think" of self-awareness we can infer, they maintain, that the self or
soul is 1) simple, 2) immaterial, 3) an identical substance and 4)
that we perceive it directly, in contrast to external objects whose
existence is merely possible. That is, the rational psychologists
claimed to have knowledge of the self as transcendentally real. Kant
believes that it is impossible to demonstrate any of these four
claims, and that the mistaken claims to knowledge stem from a failure
to see the real nature of our apprehension of the "I." Reason cannot
fail to apply the categories to its judgments of the self, and that
application gives rise to these four conclusions about the self that
correspond roughly to the four headings in the table of categories.
But to take the self as an object of knowledge here is to pretend to
have knowledge of the self as it is in itself, not as it appears to
us. Our representation of the "I" itself is empty. It is subject to
the condition of inner sense, time, but not the condition of outer
sense, space, so it cannot be a proper object of knowledge. It can be
thought through concepts, but without the commensurate spatial and
temporal intuitions, it cannot be known. Each of the four paralogisms
explains the categorical structure of reason that led the rational
psychologists to mistake the self as it appears to us for the self as
it is in itself.
We have already mentioned the Antinomies, in which Kant analyzes the
methodological problems of the Rationalist project. Kant sees the
Antinomies as the unresolved dialogue between skepticism and dogmatism
about knowledge of the world. There are four antinomies, again
corresponding to the four headings of the table of categories, that
are generated by reason's attempts to achieve complete knowledge of
the realm beyond the empirical. Each antinomy has a thesis and an
antithesis, both of which can be validly proven, and since each makes
a claim that is beyond the grasp of spatiotemporal sensation, neither
can be confirmed or denied by experience. The First Antinomy argues
both that the world has a beginning in time and space, and no
beginning in time and space. The Second Antinomy's arguments are that
every composite substance is made of simple parts and that nothing is
composed of simple parts. The Third Antinomy's thesis is that agents
like ourselves have freedom and its antithesis is that they do not.
The Fourth Antinomy contains arguments both for and against the
existence of a necessary being in the world. The seemingly
irreconcilable claims of the Antinomies can only be resolved by seeing
them as the product of the conflict of the faculties and by
recognizing the proper sphere of our knowledge in each case. In each
of them, the idea of "absolute totality, which holds only as a
condition of things in themselves, has been applied to appearances" (A
506/B534).
The result of Kant' analysis of the Antinomies is that we can reject
both claims of the first two and accept both claims of the last two,
if we understand their proper domains. In the first Antinomy, the
world as it appears to us is neither finite since we can always
inquire about its beginning or end, nor is it infinite because finite
beings like ourselves cannot cognize an infinite whole. As an
empirical object, Kant argues, it is indefinitely constructible for
our minds. As it is in itself, independent of the conditions of our
thought, should not be identified as finite or infinite since both are
categorial conditions of our thought. Kant's resolution of the third
Antinomy (A 445/B 473) clarifies his position on freedom. He considers
the two competing hypotheses of speculative metaphysics that there are
different types of causality in the world: 1) there are natural causes
which are themselves governed by the laws of nature as well as
uncaused causes like ourselves that can act freely, or 2) the causal
laws of nature entirely govern the world including our actions. The
conflict between these contrary claims can be resolved, Kant argues,
by taking his critical turn and recognizing that it is impossible for
any cause to be thought of as uncaused itself in the realm of space
and time. But reason, in trying to understand the ground of all
things, strives to unify its knowledge beyond the empirical realm. The
empirical world, considered by itself, cannot provide us with ultimate
reasons. So if we do not assume a first or free cause we cannot
completely explain causal series in the world. So for the Third
Antinomy, as for all of the Antinomies, the domain of the Thesis is
the intellectual, rational, noumenal world. The domain of the
Antithesis is the spatiotemporal world.
7. The Ideas of Reason
The faculty of reason has two employments. For the most part, we have
engaged in an analysis of theoretical reason which has determined the
limits and requirements of the employment of the faculty of reason to
obtain knowledge. Theoretical reason, Kant says, makes it possible to
cognize what is. But reason has its practical employment in
determining what ought to be as well. (A 633/B 661) This distinction
roughly corresponds to the two philosophical enterprises of
metaphysics and ethics. Reason's practical use is manifest in the
regulative function of certain concepts that we must think with regard
to the world, even though we can have no knowledge of them.
Kant believes that, "Human reason is by its nature architectonic." (A
474/B 502). That is, reason thinks of all cognitions as belonging to a
unified and organized system. Reason is our faculty of making
inferences and of identifying the grounds behind every truth. It
allows us to move from the particular and contingent to the global and
universal. I infer that "Caius is mortal" from the fact that "Caius is
a man" and the universal claim, "All men are mortal." In this fashion,
reason seeks higher and higher levels of generality in order to
explain the way things are. In a different kind of example, the
biologist's classification of every living thing into a kingdom,
phylum, class, order, family, genus, and species, illustrates reason's
ambition to subsume the world into an ordered, unified system. The
entire empirical world, Kant argues, must be conceived of by reason as
causally necessitated (as we saw in the Analogies). We must connect,
"one state with a previous state upon which the state follows
according to a rule." Each cause, and each cause's cause, and each
additional ascending cause must itself have a cause. Reason generates
this hierarchy that combines to provide the mind with a conception of
a whole system of nature. Kant believes that it is part of the
function of reason to strive for a complete, determinate understanding
of the natural world. But our analysis of theoretical reason has made
it clear that we can never have knowledge of the totality of things
because we cannot have the requisite sensations of the totality, hence
one of the necessary conditions of knowledge is not met. Nevertheless,
reason seeks a state of rest from the regression of conditioned,
empirical judgments in some unconditioned ground that can complete the
series (A 584/B 612). Reason's structure pushes us to accept certain
ideas of reason that allow completion of its striving for unity. We
must assume the ideas of God, freedom, and immortality, Kant says, not
as objects of knowledge, but as practical necessities for the
employment of reason in the realm where we can have knowledge. By
denying the possibility of knowledge of these ideas, yet arguing for
their role in the system of reason, Kant had to, "annul knowledge in
order to make room for faith." (B xxx).
8. Kant's Ethics
It is rare for a philosopher in any era to make a significant impact
on any single topic in philosophy. For a philosopher to impact as many
different areas as Kant did is extraordinary. His ethical theory has
been as, if not more, influential than his work in epistemology and
metaphysics. Most of Kant's work on ethics is presented in two works.
The Foundations of the Metaphysics of Morals (1785) is Kant's "search
for and establishment of the supreme principle of morality." In The
Critique of Practical Reason (1787) Kant attempts to unify his account
of practical reason with his work in the Critique of Pure Reason. Kant
is the primary proponent in history of what is called deontological
ethics. Deontology is the study of duty. On Kant's view, the sole
feature that gives an action moral worth is not the outcome that is
achieved by the action, but the motive that is behind the action. The
categorical imperative is Kant's famous statement of this duty: "Act
only according to that maxim by which you can at the same time will
that it should become a universal law."
a. Reason and Freedom
For Kant, as we have seen, the drive for total, systematic knowledge
in reason can only be fulfilled with assumptions that empirical
observation cannot support. The metaphysical facts about the ultimate
nature of things in themselves must remain a mystery to us because of
the spatiotemporal constraints on sensibility. When we think about the
nature of things in themselves or the ultimate ground of the empirical
world, Kant has argued that we are still constrained to think through
the categories, we cannot think otherwise, but we can have no
knowledge because sensation provides our concepts with no content. So,
reason is put at odds with itself because it is constrained by the
limits of its transcendental structure, but it seeks to have complete
knowledge that would take it beyond those limits.
Freedom plays a central role in Kant's ethics because the possibility
of moral judgments presupposes it. Freedom is an idea of reason that
serves an indispensable practical function. Without the assumption of
freedom, reason cannot act. If we think of ourselves as completely
causally determined, and not as uncaused causes ourselves, then any
attempt to conceive of a rule that prescribes the means by which some
end can be achieved is pointless. I cannot both think of myself as
entirely subject to causal law and as being able to act according to
the conception of a principle that gives guidance to my will. We
cannot help but think of our actions as the result of an uncaused
cause if we are to act at all and employ reason to accomplish ends and
understand the world.
So reason has an unavoidable interest in thinking of itself as free.
That is, theoretical reason cannot demonstrate freedom, but practical
reason must assume for the purpose of action. Having the ability to
make judgments and apply reason puts us outside that system of
causally necessitated events. "Reason creates for itself the idea of a
spontaneity that can, on its own, start to act–without, i.e., needing
to be preceded by another cause by means of which it is determined to
action in turn, according to the law of causal connection," Kant says.
(A 533/B 561) In its intellectual domain, reason must think of itself
as free.
It is dissatisfying that he cannot demonstrate freedom, nevertheless,
it comes as no surprise that we must think of ourselves as free. In a
sense, Kant is agreeing with the common sense view that how I choose
to act makes a difference in how I actually act. Even if it were
possible to give a predictive empirical account of why I act as I do,
say on the grounds of a functionalist psychological theory, those
considerations would mean nothing to me in my deliberations. When I
make a decision about what to do, about which car to buy, for
instance, the mechanism at work in my nervous system makes no
difference to me. I still have to peruse Consumer Reports, consider my
options, reflect on my needs, and decide on the basis of the
application of general principles. My first person perspective is
unavoidable, hence the deliberative, intellectual process of choice is
unavoidable.
b. The Duality of the Human Situation
The question of moral action is not an issue for two classes of
beings, according to Kant. The animal consciousness, the purely
sensuous being, is entirely subject to causal determination. It is
part of the causal chains of the empirical world, but not an
originator of causes the way humans are. Hence, rightness or
wrongness, as concepts that apply to situations one has control over,
do not apply. We do not morally fault the lion for killing the
gazelle, or even for killing its own young. The actions of a purely
rational being, by contrast, are in perfect accord with moral
principles, Kant says. There is nothing in such a being's nature to
make it falter. Its will always conforms with the dictates of reason.
Humans are between the two worlds. We are both sensible and
intellectual, as was pointed out in the discussion of the first
Critique. We are neither wholly determined to act by natural impulse,
nor are we free of non-rational impulse. Hence we need rules of
conduct. We need, and reason is compelled to provide, a principle that
declares how we ought to act when it is in our power to choose
Since we find ourselves in the situation of possessing reason, being
able to act according to our own conception of rules, there is a
special burden on us. Other creatures are acted upon by the world. But
having the ability to choose the principle to guide our actions makes
us actors. We must exercise our will and our reason to act. Will is
the capacity to act according to the principles provided by reason.
Reason assumes freedom and conceives of principles of action in order
to function.
Two problems face us however. First, we are not wholly rational
beings, so we are liable to succumb to our non-rational impulses.
Second, even when we exercise our reason fully, we often cannot know
which action is the best. The fact that we can choose between
alternate courses of actions (we are not determined to act by instinct
or reason) introduces the possibility that there can be better or
worse ways of achieving our ends and better or worse ends, depending
upon the criteria we adopt. The presence of two different kinds of
object in the world adds another dimension, a moral dimension, to our
deliberations. Roughly speaking, we can divide the world into beings
with reason and will like ourselves and things that lack those
faculties. We can think of these classes of things as
ends-in-themselves and mere means-to-ends, respectively.
Ends-in-themselves are autonomous beings with their own agendas;
failing to recognize their capacity to determine their own actions
would be to thwart their freedom and undermine reason itself. When we
reflect on alternative courses of action, means-to-ends, things like
buildings, rocks, and trees, deserve no special status in our
deliberations about what goals we should have and what means we use to
achieve them. The class of ends-in-themselves, reasoning agents like
ourselves, however, do have a special status in our considerations
about what goals we should have and the means we employ to accomplish
them. Moral actions, for Kant, are actions where reason leads, rather
than follows, and actions where we must take other beings that act
according to their own conception of the law, into account.
c. The Good Will
The will, Kant says, is the faculty of acting according to a
conception of law. When we act, whether or not we achieve what we
intend with our actions is often beyond our control, so the morality
of our actions does not depend upon their outcome. What we can
control, however, is the will behind the action. That is, we can will
to act according to one law rather than another. The morality of an
action, therefore, must be assessed in terms of the motivation behind
it. If two people, Smith and Jones, perform the same act, from the
same conception of the law, but events beyond Smith's control prevent
her from achieving her goal, Smith is not less praiseworthy for not
succeeding. We must consider them on equal moral ground in terms of
the will behind their actions.
The only thing that is good without qualification is the good will,
Kant says. All other candidates for an intrinsic good have problems,
Kant argues. Courage, health, and wealth can all be used for ill
purposes, Kant argues, and therefore cannot be intrinsically good.
Happiness is not intrinsically good because even being worthy of
happiness, Kant says, requires that one possess a good will. The good
will is the only unconditional good despite all encroachments.
Misfortune may render someone incapable of achieving her goals, for
instance, but the goodness of her will remains.
Goodness cannot arise from acting on impulse or natural inclination,
even if impulse coincides with duty. It can only arise from conceiving
of one's actions in a certain way. A shopkeeper, Kant says, might do
what is in accord with duty and not overcharge a child. Kant argues,
"it is not sufficient to do that which should be morally good that it
conform to the law; it must be done for the sake of the law."
(Foundations of the Metaphysics of Morals, Akademie pagination 390)
There is a clear moral difference between the shopkeeper that does it
for his own advantage to keep from offending other customers and the
shopkeeper who does it from duty and the principle of honesty.(Ibid.,
398) Likewise, in another of Kant's carefully studied examples, the
kind act of the person who overcomes a natural lack of sympathy for
other people out of respect for duty has moral worth, whereas the same
kind act of the person who naturally takes pleasure in spreading joy
does not. A person's moral worth cannot be dependent upon what nature
endowed them with accidentally. The selfishly motivated shopkeeper and
the naturally kind person both act on equally subjective and
accidental grounds. What matters to morality is that the actor think
about their actions in the right manner.
We might be tempted to think that the motivation that makes an action
good is having a positive goal–to make people happy, or to provide
some benefit. But that is not the right sort of motive, Kant says. No
outcome, should we achieve it, can be unconditionally good. Fortune
can be misused, what we thought would induce benefit might actually
bring harm, and happiness might be undeserved. Hoping to achieve some
particular end, no matter how beneficial it may seem, is not purely
and unconditionally good. It is not the effect or even the intended
effect that bestows moral character on an action. All intended effects
"could be brought about through other causes and would not require the
will of a rational being, while the highest and unconditional good can
be found only in such a will." (Ibid., 401) It is the possession of a
rationally guided will that adds a moral dimension to one's acts. So
it is the recognition and appreciation of duty itself that must drive
our actions.
d. Duty
What is the duty that is to motivate our actions and to give them
moral value? Kant distinguishes two kinds of law produced by reason.
Given some end we wish to achieve, reason can provide a hypothetical
imperative, or rule of action for achieving that end. A hypothetical
imperative says that if you wish to buy a new car, then you must
determine what sort of cars are available for purchase. Conceiving of
a means to achieve some desired end is by far the most common
employment of reason. But Kant has shown that the acceptable
conception of the moral law cannot be merely hypothetical. Our actions
cannot be moral on the ground of some conditional purpose or goal.
Morality requires an unconditional statement of one's duty.
And in fact, reason produces an absolute statement of moral action.
The moral imperative is unconditional; that is, its imperative force
is not tempered by the conditional "if I want to achieve some end,
then do X." It simply states, do X. Kant believes that reason dictates
a categorical imperative for moral action. He gives at least three
formulations of the Categorical Imperative.
1. "Act only according to that maxim by which you can at the same
time will that it should become a universal law." (Ibid., 422)
2. "Act as though the maxim of your action were by your will to
become a universal law of nature." (Ibid)
3. Act so that you treat humanity, whether in your own person or in
that of another, always as an end and never as a means only." (Ibid.,
429)
What are Kant's arguments for the Categorical Imperative? First,
consider an example. Consider the person who needs to borrow money and
is considering making a false promise to pay it back. The maxim that
could be invoked is, "when I need of money, borrow it, promising to
repay it, even though I do not intend to." But when we apply the
universality test to this maxim it becomes clear that if everyone were
to act in this fashion, the institution of promising itself would be
undermined. The borrower makes a promise, willing that there be no
such thing as promises. Thus such an action fails the universality
test.
The argument for the first formulation of the categorical imperative
can be thought of this way. We have seen that in order to be good, we
must remove inclination and the consideration of any particular goal
from our motivation to act. The act cannot be good if it arises from
subjective impulse. Nor can it be good because it seeks after some
particular goal which might not attain the good we seek or could come
about through happenstance. We must abstract away from all hoped for
effects. If we remove all subjectivity and particularity from
motivation we are only left with will to universality. The question
"what rule determines what I ought to do in this situation?" becomes
"what rule ought to universally guide action?" What we must do in any
situation of moral choice is act according to a maxim that we would
will everyone to act according to.
The second version of the Categorical Imperative invokes Kant's
conception of nature and draws on the first Critique. In the earlier
discussion of nature, we saw that the mind necessarily structures
nature. And reason, in its seeking of ever higher grounds of
explanation, strives to achieve unified knowledge of nature. A guide
for us in moral matters is to think of what would not be possible to
will universally. Maxims that fail the test of the categorical
imperative generate a contradiction. Laws of nature cannot be
contradictory. So if a maxim cannot be willed to be a law of nature,
it is not moral.
The third version of the categorical imperative ties Kant's whole
moral theory together. Insofar as they possess a rational will, people
are set off in the natural order of things. They are not merely
subject to the forces that act upon them; they are not merely means to
ends. They are ends in themselves. All means to an end have a merely
conditional worth because they are valuable only for achieving
something else. The possessor of a rational will, however, is the only
thing with unconditional worth. The possession of rationality puts all
beings on the same footing, "every other rational being thinks of his
existence by means of the same rational ground which holds also for
myself; thus it is at the same time an objective principle from which,
as a supreme practical ground, it must be possible to derive all laws
of the will." (Ibid., 429)
9. Kant's Criticisms of Utilitarianism
Kant's criticisms of utilitarianism have become famous enough to
warrant some separate discussion. Utilitarian moral theories evaluate
the moral worth of action on the basis of happiness that is produced
by an action. Whatever produces the most happiness in the most people
is the moral course of action. Kant has an insightful objection to
moral evaluations of this sort. The essence of the objection is that
utilitarian theories actually devalue the individuals it is supposed
to benefit. If we allow utilitarian calculations to motivate our
actions, we are allowing the valuation of one person's welfare and
interests in terms of what good they can be used for. It would be
possible, for instance, to justify sacrificing one individual for the
benefits of others if the utilitarian calculations promise more
benefit. Doing so would be the worst example of treating someone
utterly as a means and not as an end in themselves.
Another way to consider his objection is to note that utilitarian
theories are driven by the merely contingent inclination in humans for
pleasure and happiness, not by the universal moral law dictated by
reason. To act in pursuit of happiness is arbitrary and subjective,
and is no more moral than acting on the basis of greed, or
selfishness. All three emanate from subjective, non-rational grounds.
The danger of utilitarianism lies in its embracing of baser instincts,
while rejecting the indispensable role of reason and freedom in our
actions.
10. References and Further Reading
* Anthropology from a Pragmatic Point of View, trans. Victor Lyle
Dowden. Southern Illinois University Press, 1996.
* The Conflict of the Faculties, trans. Mary Gregor. Lincoln:
University of Nebraska Press, 1992.
* Correspondence. ed. Arnulf Zweig. New York: Cambridge University
Press, 1999.
* Critique of Judgment, trans. Werner S. Pluhar. Indianapolis:
Hackett, 1987.
* Critique of Practical Reason, trans. Mary Gregor. New York:
Cambridge University Press, 1997.
* Critique of Pure Reason, trans. Werner Pluhar. Indianapolis:
Hackett, 1996.
* Groundwork of the Metaphysics of Morals. ed. Mary Gregor. New
York: Cambridge University Press, 1998.
* Kant's Latin Writings, Translations, Commentaries, and Notes,
trans. Lewis White Beck in collaboration with Mary Gregor, Ralf
Meerbote, John Reuscher. New York: Peter Lang, 1986
* Kant: Philosophical Correspondence 1759-1799, ed. and trans.
Arnulf Zweig. Chicago: Chicago University Press, 1967.
* Logic, trans. Robert S. Hartman and Wolfgang Schwarz. New York:
Dover Publications, 1974.
* Metaphysical Foundations of Natural Science, trans. James
Ellington. Indianapolis: Hackett, 1975.
* The Metaphysics of Morals. trans. Mary Gregor. New York:
Cambridge University Press, 1996.
* Opus Postumum, ed. Eckart Forster, trans. Eckart Forster and
Michael Rosen. Cambridge: Cambridge University Press, 1993.
* Prolegomena to Any Future Metaphysics, trans. Gary Hatfield. New
York: Cambridge University Press, 1997.
* Religion within the Limits of Reason Alone. trans. T.M. Greene
and H.H. Hudson. New York: Harper and Row, 1960.
* Theoretical Philosophy, trans. David Walford and Ralf Meerbote.
Cambridge: Cambridge University Press, 1992.
* What Real Progress Has Metaphysics Made in Germany Since the
Time of Leibniz and Wolff?(1804). trans. T. Humphrey. New York:
Abaris, 1983 (Ak. XX).
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