The Philosophy Book

168 IMMANUEL KANT

my concept of some type of thing

(books) and my concept of a “thing”

as such (substance). A concept

such as substance defines what

it means to be a thing in general

rather than defining some type

of thing like a book. My intuition

of a book and the concept of a book

are empirical, for how could I know

anything about books unless I had

come across them in the world?

But my intuition of space and time

and the concept of substance are

a priori, meaning that they are

known before or independently

of any experience.

A true empiricist would argue

against Kant that all acquaintances

come from experience—in other

words, nothing is a priori. They

Kant split knowledge into intuitions, gained

from direct sensibility of the world, and concepts,

which come indirectly from our understanding.

Some of our knowledge—both of sensibility and

understanding—comes from empirical evidence,

while some is known a priori.

For example, the experimental
physicist Galileo Galilei wanted to
test the hypothesis that two things
of different weights will nevertheless
fall through the air at the same rate.
He designed an experiment to test
this in such a way that the only
possible explanation of the observed
result would be the truth or falsity
of the hypothesis.
Kant identifies the nature and
importance of the scientific method.
He believes that this method had
put physics and other subjects on
the “secure road of a science.”
However, his investigations do not
stop there. His next question is:
“Why is our experience of the world
such that the scientific method
works?” In other words, why is our
experience of the world always
mathematical in nature, and how
is it always possible for human
reason to put questions to nature?

Intuitions and concepts
In his most famous work, Critique
of Pure Reason, Kant argues that
our experience of the world involves
two elements. The first is what he
calls “sensibility”—our ability to be
directly acquainted with particular
things in space and time, such as
this book you are reading now.

These direct acquaintances he

calls “intuitions.” Second is what

Kant calls the “understanding”, our

ability to have and use concepts.

For Kant, a concept is an indirect

acquaintance with things as

examples of a type of thing, such

as the concept of “book” in general.

Without concepts we would not

know our intuition was of a book;

without intuitions we would never

know that there were books at all.

Each of these elements has, in

turn, two sides. In sensibility, there

is my intuition of a particular thing

in space and time (like the book)

and my intuition of space and time

as such (my acquaintance with

what space and time are like in

general). In understanding, there is

Thoughts without content

are empty; intuitions

without concepts are

blind... only from their

union can cognition arise.

Immanuel Kant

Key

Empirical

knowledge

A priori

knowledge

intuition of

space and time

the concept of substance

the concept “book”

intuition of a

particular book