Philosophy as Critique
Kant’s three major volumes are entitled critiques,
and his entire philosophy focuses on applying his critical method
to philosophical problems. The correct method in philosophy, according
to Kant, is not to speculate on the nature of the world around us
but to perform a critique of our mental faculties, investigating
what we can know, defining the limits of knowledge, and determining
how the mental processes by which we make sense of the world affect
what we know. This change in method represents what Kant calls a
Copernican revolution in philosophy. Just as Copernicus turned astronomy on
its head in the sixteenth century by arguing that the sun, not the earth,
is the center of the solar system, Kant turns philosophy on its head
by arguing that we will find the answers to our philosophical problems
in an examination of our mental faculties rather than in metaphysical
speculation about the universe around us. One part of this revolution
is the suggestion that the mind is not a passive receptor but that
it actively shapes our perception of reality. Another is a general
shift, which remains to this day, from metaphysics toward epistemology.
That is, the question of what reality actually consists of has become
less central than the question of what we can know about reality
and how we can know it.
The Philosophy of Transcendental Idealism
Kant’s emphasis on the role our mental faculties play
in shaping our experience implies a sharp distinction between phenomena and noumena.
Noumena are “things-in-themselves,” the reality that exists independent
of our mind, whereas phenomena are appearances, reality as our mind
makes sense of it. According to Kant, we can never know with certainty
what is “out there.” Since all our knowledge of the external world
is filtered through our mental faculties, we can know only the world
that our mind presents to us. That is, all our knowledge is only
knowledge of phenomena, and we must accept that noumena are fundamentally
unknowable. Idealism is the name given to the various
strands of philosophy that claim the world is made up primarily
of mental ideas, not of physical things. Kant differs from many
idealists in that he does not deny the existence of an external
reality and does not even think that ideas are more fundamental
than things. However, he argues that we can never transcend the
limitations and the contextualization provided by our minds, so
that the only reality we will ever know is the reality of phenomena.
The Category of the Synthetic A Priori
Kant inherits from Hume the problem of how we can infer
necessary and universal truths from experience when all experience
is by its nature contingent and particular. We actually experience
individual sights and sounds and so on. We cannot “experience” a
physical law or a relation of cause and effect. So if we cannot
see, smell, or hear causation, how can we infer that some events
cause others? Kant phrases this question more generally as the question
of how synthetic a priori knowledge is possible. That is, how can
we know things that are necessary and universal but not self-evident
or definitional? Kant’s ingenious solution is that synthetic a priori
knowledge is possible because our mental faculties organize experience according
to certain categories so that these categories become necessary
and universal features of our experience. For instance, we do not
find causation in nature so much as we cannot not find
causation in nature. It is a feature of the way our minds make sense
of reality that we perceive causes and effects everywhere at work.
For Kant, then, the category of the synthetic a priori is the key
to explaining how we gain substantive knowledge about the world.
Deontological Ethics
Ethical theorists can be roughly divided into two camps:
those who consider an action moral or immoral depending on the motive behind
it and those who consider an action moral or immoral depending on
the consequences it produces. Kant is firmly in the former camp,
making him a deontologist rather than a consequentialist when it
comes to ethics. (The word deontology derives from the
Greek roots deon, “duty,” and logos,
“science.”) Kant argues that we are subject to moral judgment because
we are able to deliberate and give reasons for our actions, so moral
judgment should be directed at our reasons for acting. While we
can and should take some care to ensure that our actions produce
good consequences, the consequences of our actions are not themselves
subject to our reason, so our reason is not fully responsible for
the consequences of the actions it endorses. Reason can only be
held responsible for endorsing certain actions, and so it is only
the actions, and the motives behind them, that are open to moral
judgment.
The Ethics of Autonomy
Every theory of ethics must give an answer to the question
“Or else what?” That is, we must be able to explain why good is
good and bad is bad. Christians answer the “Or else what?” question
with the threat of eternal damnation, while Utilitarians answer
that, since happiness is the greatest good, bad actions produce
unhappiness, and unhappiness is bad in and of itself. Kant, by contrast,
argues that since reason is the source of morality, goodness and
badness should be dictated by reason. To act badly, according to
Kant, is to violate the maxims laid out by one’s reason, or to formulate
maxims that one could not consistently will as universal laws. In
other words, immorality is a form of irrationality: badness results
from violating the laws of reason. According to Kant, our rationality
is what makes us human, so by acting irrationally, and hence immorally,
we also compromise our humanity. Kant’s answer to the question “Or
else what?” is that we diminish ourselves as rational human beings
by acting immorally. Only by behaving rationally do we show ourselves
to be autonomous beings, in control of the passions and appetites
that might lead us to act against our better judgment.
