Friday, October 19, 2012

Why We Need Intuitions AND Concepts

OK, says Kant in the first Critique.  You could say that appearances that we get from our senses chunked together with intuitions are all there is.  Just as Hume suggests with his "associationism."  That's the point of his setup before the Transcendental Deduction:
Appearances might very well be so constituted that the understanding should not find them to be in accordance with the conditions of its unity.  And everything might lie in such confusion that, e.g., in the succession of appearances nothing would offer itself that would furnish a rule of synthesis and thus answer to the concept of cause and effect, so that this concept therefore would be entirely empty, nugatory, and without significance.  Appearances would nonetheless offer objects to our intuition, for intuition by no means requires the functions of thinking. (B123/A90)
Sorry to punch all that out, but it's important.  Kant here is making Hume's argument.  Hey, maybe our mind just gathers up appearances in a bundle and reads the patterns therein.  So maybe we just note the patterns and say, wow, there's a pattern here!  First the sun rose yesterday, and then it rose today!  Maybe there's a pattern here.  No need for analysis; no need for thinking; no need for concepts.

But Kant cannot accept this.  When we "cognize" an object, he claims, we do more than make a reactive burp in response to sense impressions.  And  so he lurches into the Transcendental Deduction to prove that we synthesize our bundle of intuitions using the forms of intuition in space and time and concepts derived from the categories, and then we unify the synthesis into a judgment about an object in an act of apperception, of a self-conscious validity claim.

Kant calls this objective validity, which is a bit of a push, since he's talking about a "valid" cognizing of a unity of synthesized intuitions with the help of the concepts of the understanding into a unified "object."  The notion of "objective validity" is obtained by calling things by the conveniently right names.

For us, the interesting thing about Kant's argument is its foreshadowing of the modern approach to reality.  Kant is claiming that we are not really passive consumers of appearances, but purposeful actors.  We take the stuff coming in over the transom and organize it in our minds in a strategic effort to understand and judge what is going on out there in the tough and challenging world.  We process our sense data and then construct in our minds a picture of what we have seen.  We "think" what we see and advance our claim of what we have seen and what we judge we have seen.

Forget Hume, Kant says.  I offer you a whole new world of active, purposeful "cognizing."

Thursday, October 18, 2012

Kant's Best Shot: "Objective Reality"

In the Transcendental Deduction, Kant hauls out his big gun against Hume's "associationism:" he calls it "objective reality."  The idea is that if you run your lumber through Kant's three-stage lumber mill, inserting raw logs of sense impressions into the circular saw that slices the sense impressions through the forms of intuition, and then you assemble the manifold of resulting log intuitions into the synthesis of a stacked pallet, then you can judge the resulting stack of Grade A two-by-fours as a "necessary unit of the apperception in the synthesis of intuitions."

Why is this objective?  Because writes Kant, "[the] transcendental unity of apperception is that unity through which all of the manifold given in an intuition is united in the concept of the object.  It is called objective on that account[.]"(§18, B140)  Get it?  Since the thinker has united his manifold of sense impressions into a unified single object, he now has an objective reality.  The "subjective unity of  consciousness"  (Hume's association) is merely a "determination of inner sense" without the uniting into a single object.

So while we have merely a bundle of sense impressions we don't have a unified object, and therefore no objective reality.

What Kant seems to be trying to argue is that an objectively valid judgement is one that makes a claim, an assertoric judgment, as "this body is heavy."  This is a claim that can be agreed to or denied by others.  The statement that "bodies and heaviness seem to go together," i.e., a weaker claim than Kant's phrase "If I carry a body I feel a pressure of weight" comes closer to the Humean idea of a bundle of impressions.

But really, it seems to be much more sensible to accept Hume's skepticism that you can never really apply objective criteria to a truth claim about an association, and move to modern neo-pragmatism and say that look, the science is settled on this, at least a low velocities, so we know, from our concepts of the understanding, that bodies are heavy and bodies of gold are really heavy.  Until someone proves us wrong.

Wednesday, October 17, 2012

"Thoughts without content are empty"

It's one of the most quoted zingers in Kant's Critique of Pure Reason.
Thoughts without content are empty.  Intuitions without concepts are blind.
OK.  So what is the chap talking about?  Kant's whole game is to deal with the David Hume challenge, his so-called "associationism."  On this view we humans are more or less passive consumers of a bundle of sense impressions of the real world.  Kant's strategy is to turn this on its head.  No we don't associate sense impressions with the real world.  We take formless sense impressions, view them with the forms of intuition about space and time, synthesize them with intuitions, and then own them as ours by applying the pure concepts of the understanding to our intuitions and finally applying judgments.

The experts call this the "togetherness principle."  You need both concepts and intuitions to achieve useful judgments about the world as it appears to you.   Kant repeats his famous apothegm several times:
  • "[N]either concepts without intuition corresponding to them in some way nor intuition without concepts can yield a cognition."
  • "Thus pure intuition contains merely the form under which something is intuited, and pure concept only the form of thinking of an object in general."
  • "Without sensibility no object would be given to us, and without understanding none would be thought."
  • "The understanding is not capable of intuiting anything, and the senses are not capable of thinking anything."
All along, Kant is arguing for the importance of both intuition and concepts in full human cognition.  Thus, Kant might have made things clearer had he written:
Thoughts without sensible content cannot apply to the real world; intuitions without rational concepts cannot be used for judgment.
For all its famous difficulty.  Kant's Critique does have its moments.

Tuesday, October 16, 2012

Are Space and Time Real?

We humans are born, live, and die, and experience ourselves moving through time.  We open our eyes and see objects before us.  It seems sensible to see space as a container, as Plato did, and time as the flow of a river.  But are they real?  Can we speak as Newton did of absolute space and time?

The early modern era brought these questions into sharp relief, and by the time that Kant came along there were several contesting notions abroad, from Newton's absolute space and time--though he insisted that humans could only experience relative space and time--to Bishop Berkeley's idealist notion that we cannot experience absolute space and time and so should content ourselves with experiencing sensible things.  For Hume, impressions come before ideas, so space is our interpretation of a bundle of impressions that seems to suggest extension.

Kant's Big Idea is to drive his ship between the Scylla of absolute space and time and the Charybdis of external impressions.  He doesn't want to prejudge the world as real, for Berkeley shows that our ideas of the world are all in the mind.  But he doesn't want to concede to Hume that the world imprints itself upon us.  Thus for him space and time are forms of intuition independent of experience.  They form a mental framework, forms of intuition, that the mind uses to make sense of sensible impressions.  Says he:
By means of outer sense [i.e. physical sensations of external objects]... we represent objects as outside us, and all as in space.
But he argues that the "representation of space" can't be obtained from experience but rather that "outer experience is itself possible only through this representation."  We do not get our experience from outside; we manufacture it inside us, and only then apply it to the outside world.

This is a theme that repeats itself again and again in Kant, and you can see that it comes down to us in current notions of the way that science works.  You have a problem, so you gather some data.  Then you come up with a theory in your mind, a mental idea of how the world works.  You test it against the data.  If it works, your mental idea is your new view of the world.  Until your wonderful theory crashes and burns and another theory comes up and supersedes it.

Now Kant does not consider space as an illusion, existing only in the mind.  He argues the reality of space for "everything that comes before us externally as an object."  But he insists on the "transcendental ideality" of space when we are talking about things in themselves.

When it comes to time, Kant asserts that "time is nothing other than the form of inner sense, i.e., of the intuition of our self and our inner state."  And it is a necessary condition of our experience of space as well, because we could not experience external objects unless they were experienced in time.

Again, Kant asserts the "empirical reality of time" an an objective reality of all "objects that may ever be given to our senses."  But not "absolute time". That "transcendental ideality" could "never be given to us through the senses."