Immanuel Kant and the Late Moderns
Immanuel Kant achieved philosophy’s reconciliation with science after Hume had skeptically
pushed science away.
Kant saw a structural similarity between metaphysics and science.
Critique of Pure Reason (1781) laid bare this structural similarity, which concerned hypotheses
necessary to explain understanding.
The critical question was whether the human mind had the
powers to know anything a priori, or prior to experience.
If an understanding was necessary for our
experience to be what it is, then the answer was yes.
Kant agreed with Hume that all knowledge
began with experience, but added “though our knowledge begins with experience, it does not follow
that it all arises out of experience.”
We do not directly sense or experience causality, but we have
real knowledge about causality from the mind’s faculty of rational judgment.
We must understand,
then, rational judgment.
To define rational judgment we recognized there was, in fact, a priori knowledge.
question was not whether a priori knowledge existed, but, “Is synthetic a priori knowledge possible?”
Yes, it is.
A synthetic a priori metaphysical assertion was “man is free to choose.”
adds new knowledge to the concept of the subject, so it is synthetic.
And we connect the predicate
free to all men before we have met all men, so it is a priori.
Based on this, Kant proposed a new
hypothesis concerning the relation between the mind and its objects, namely that objects conform to
the operations of the mind, not vice-versa as Hume had proposed.
So, with Hume, our knowledge
began with experience, but, in addition to Hume, the mind was an active agent and imposed a
structure on the objects it knew and organized the experience of those objects.
For Kant, the mind brought to the raw materials of experience, first, the forms of intuition
called space and time.
Space and time did not emerge from our sensory experience, nor were they
concepts, but rather part of the lenses of the understanding through which we saw all objects of
The forms of intuition helped synthesize and unify our experience, just like the other
categories of thought.
These categories of thought interpreted the world of sense by means of
certain fixed forms of concepts, such as quantity, quality, relation, and modality.
understood according to quantity, we had in mind one or many.
When we understood according to
quality, we had in mind a negative or positive judgment.
When we understood according to relation,
we had in mind either cause and effect or the relation of a subject to a predicate.
understood according to modality, we had in mind that something is either possible or impossible.
These categories of understanding and forms of intuition synthesized our experience into unities of