1. Kant: motivations and his transcendental argument

The skepticism of the Scottish philosopher David Hume woke the Prussian philosopher Immanuel Kant from the “dogmatic slumber” of his own rationalism. Kant credited Hume with a devastating demolition of our ability to justify our knowledge claims. Because Kant was a thinker who was deeply committed to the role of reason in governing both our claims to knowledge and our ability to live worthwhile practical lives, he took it upon himself to reconstruct the foundations of knowledge after Hume’s devastating demolition. In this way Kant’s task was analogous to Descartes’ task some 150 years earlier. Both, in the face of a crisis in our ability to determine what we can know, attempted to create a groundwork (“Grundlegung”) on which we can build knowledge of both the theoretical world of ideas and the practical world of conscious action.

Kant’s approach begins by giving due credit to the empiricist tradition’s investigation into the nature and the capacities of the mind. Kant says that this investigation raises a key question: What norms can we use when we investigate the nature and capacities of the mind’s ability to know the world? Kant sees two alternatives.

One is to look to the world of facts and evaluate what we know and what we can know by looking at the way the world is. Kant calls this sort of approach an external or transcendent (because it investigates the mind by going beyond or transcending the mind) critique. In contemporary terms, this is the approach of fields like neuropsychology and evolutionary psychology. They begin by taking our understand of how the brain or how evolution works and then use this understanding to investigate the mind. Kant is critical of this approach for two reasons. First, it already assumes that we can have knowledge of the external world. This, though, is the very question we want to investigate. It “begs the question.” It assumes what we are trying to prove. Second, facts are not norms or standards of evaluation. Even if we can understand how the mind works by studying the brain, this provides no insight into how the mind should work. For example, understanding how the brain of a schizophrenic works provides no insight into whether the mind of a schizophrenic accurately comprehends the world. Thus, transcendent critique is not the means by which we can investigate the nature and capacities of the mind’s ability to know the world.

The second approach is to use the norms and criteria of reason to investigate the nature and capacities of the mind’s ability to know the world. Kant call this approach an immanent critique. Kant also rejects this approach because it is also question begging. You cannot assume the correct working of the mind in order to investigate whether the mind works correctly. This was part of Hume’s great lesson to philosophy. If you cannot assume rational foundations for the correct functioning of mind and if you cannot discover the grounds for the mind’s rational functioning in experience, then you have no way to justify our ability to know the world.

Kant sees Hume as confronting philosophy with a destructive dilemma. We can neither use transcendent or immanent critique to have knowledge. What, then, are we to do?

In logic when you have a destructive dilemma, one way to avoid the destructive consequence is to “go between the horns” of the dilemma. This means finding a third alternative.

Kant’s alternative is one of Kant’s many great contributions to philosophy. This is what Kant calls “a transcendental” critique. In a transcendental critique, you look at some essential capacity or ability and then you determine what is necessary for that capacity.

Okay, that is really abstract!

So, let’s try an example.

We all have sensations. We see a certain thing at a certain time. You are, as you read this, seeing words on a screen. The capacity to have sensation is called by Kant “sensibility.” Kant asks, what must be the case for you to be able to see the words you are reading on the screen? What must be the case for you to smell honey or hear the buzzing of bees? What are, to use Kant’s language, “the necessary conditions for the possibility of sensibility”? This is a transcendental question because it takes a capacity we all take for granted, in this case sensibility, and then asks, what has to be true if we are to have that capacity? These kinds of questions are for Kant transcendental questions.

A transcendental question asks: What are the necessary conditions for … [insert here some basic capacity that we all exercise] …?

Kant asks these transcendental questions in order to solve all sorts of fundamental philosophical problems.

What are the necessary conditions for sensibility?

What are the necessary conditions for understanding (our making sense of how the world works)?

What are the necessary conditions for morality? (This question leads to Kant’s practical philosophy or ethics.)

Okay, so these are some of Kant’s transcendental questions; what, then, are the answers?

What are the necessary conditions for the possibility of smelling the scent of honey or hearing the buzzing of bees? Kant argues that all sensation is the sensations of something somewhere and somewhen. In other words, Kant says that space and time are necessary conditions for the possibility of sensibility. To, again use Kant’s language, space and time are transcendentally real. He goes on to call space and time “pure intuitions.” They are pure because they are untouched by experience. Because of this they are also a priori, justifiable without recourse to experience.

What are the necessary conditions for the possibility of seeing the bees going from flower to beehive and seeing over the course of the summer the beehive filling with honey and then concluding that bees make honey from the nectar of flowers? What are the necessary conditions for the possibility of understanding? The details of the answer to this are quite complicated and well beyond the scope of an Introduction to Philosophy class. However, the overall approach is Kant’s argument that we use categories of understanding to put together our sensations to make sense of the world. For example, you see a bee. You hear a buzzing from the place you see the bee. You make a causal inference that the bee is making the buzzing. Without the category of causation, you would never make the connection that the bee is buzzing.

Causation, then is a necessary condition for the possibility of understanding.

For Kant, understanding and sensibility go hand in hand. Together, they constitute experience.

Kant writes:

“the faculty for thinking the object of sensory intuition is the understanding”

“Without sensibility no object would be given to us, and without understanding no object would be thought by us. Thoughts without content are empty, intuitions without concepts are blind. Hence, it is just as necessary to make one’s concepts sensible (i.e., to adjoin an object to them in an intuition), as it is to make one’s intuitions intelligible (i.e., to bring them under concepts).”

2. Kant and the Modern Hume’s Fork

Kant describes his transcendental approach understanding as:

“the analysis of the faculty of understanding itself, so as to investigate the possibility of a priori concepts by seeking that possibility in the understanding alone (as the birthplace of those concepts), and by analyzing the pure use of those concepts.”

What is important here is Kant’s notion that the categories of understanding are a priori concepts. That is, knowledge claims whose justification does not depend on experience. For example, if it can be shown that causal inference is a priori, then Hume’s empiricist demolition of the use of causal connection no longer works. If Kant can show that the foundational categories of understanding are justifiable a priori, then he has saved knowledge from skepticism!

If you recall from the Hume reading, at the root of Hume’s skepticism is the distinction between relations of ideas (RoI) and matters of fact (MoF). Relations of Ideas are knowable without experience. They are a priori. Hume also claims that they can provide no information about how the world works. Matters of fact on the other hand, are informative about the world, but are only knowable through experience. They are posteriori. Hume argues that if causation, for example, is to be explanatory of the way the world works, it must be derived from experience. Since we cannot justify causation through experience, we are not rationally justified in using it to explain the world.

Kant’s solution to this is to claim the we can have a priori ideas that can be used to understand how the way the world works. He calls these ideas “synthetic a priori.”

It works like this:

Modern Hume’s Fork

	A priori	Posteriori or Empirical
Analytic	“All bachelors are unmarried men” All analytic knowledge is a priori.	NONE
Synthetic or Ampliative	? Here Empiricists and Kant disagree Empiricists (Hume): NO! Transcendental Idealists (Kant): YES!	“Today it is raining.” All a posteriori knowledge is synthetic.

This chart shows a two-part distinction.

In the left-hand column there is a distinction between “analytic” and “synthetic” propositions. This distinction is concerned with the relation in a proposition between the subject and the predicate.

Analytic propositions are what Hume calls “Relations of Ideas.” They have the logical structure of “A is A.” These are identity statements.

(Remember a proposition is: Subject/verb to be/Predicate: All dogs/are/canids. All dogs are canids is an analytic proposition because “canid” means “kind of dog.”)

Synthetic propositions are propositions where the predicate adds to what we know in the subject. An example of a synthetic proposition is, all dogs are social animals. Dogs are not, by definition, social. That is something we have learned about dogs through observation.

On to top row is the distinction between a priori and posteriori, this, as I have already explained, is an epistemic distinction. It separates a priori claims that can be justified without experience and a posteriori claims that need to be justified by experience.

We can justify a priori the truth of the claim that all dogs are canids. Because this claim can be justified without reliance on experience everyone can know that it is true no matter what their experience is. Even if you have never seen a dog, you can justify to truth of the claim that all dogs are canids. Thus, to use Kant’s claim, all dogs are canids is a universal truth. A priori claims are also, Kant claims, necessarily true. In other words, they cannot be other than truth. This is the same thing that Hume says about Relations of Ideas when he says that they are “certain.” Certain here means necessarily true.

We need to justify posteriori the truth of the claim that dogs are social animals.

On the basis of these distinctions, Hume’s Relations of Ideas are analytic a priori. Hume’s Matters of Fact are synthetic posteriori.

Kant adds to this a third category, the synthetic a priori. Synthetic a priori propositions are propositions where the predicate adds information to what is said in the subject (and thus are synthetic) and are justifiable without reliance on experience (and thus are a priori).

If we accept Kant’s proposal, that we can justify propositions such as, “Events in the world are linked by causal relations,” then we can overcome Hume’s skeptical conclusions. We can justify our claims about how the world works because the foundational concepts that we use such as causation, induction, identity over time, time itself, etc. can be justified as a priori synthetic concepts.

This, however, comes at a cost.

First, though, watch the following:

(Video also available at https://www.wi-phi.com/videos/kant-on-metaphysical-knowledge/)

3. Kant’s Copernican Revolution

In his great treatise, the Critique of Pure Reason, Kant writes:

Until now it has been assumed that all our knowledge must conform to the objects; but working on that basis we have never succeeded in learning anything—never added anything to our stock of knowledge—in an a priori way through concepts. So, let us now experiment with doing metaphysics on the basis of the assumption that the objects must conform to our knowledge. That would fit better with the upshot that we want, namely a priori knowledge of the objects that will tell us something definite about them before they are given to us. [Here, ‘given to us’ means ‘presented to us in sense-experience’. If the knowledge in question were available to us only after the objects were given to us, it wouldn’t be a priori, and so it wouldn’t be metaphysics.] This would be like Copernicus’s basic idea: having found that he wasn’t getting far with explaining the movements of the heavenly bodies while assuming that the whole flock of them was revolving around the observer, he tried making the observer revolve and leaving the stars at rest. Well, in metaphysics we can try the same idea as applied to the intuition of objects. (CPR, xvi)

In the first sentence of this paragraph Kant alludes to what is often called the “correspondence theory of knowledge.” This is the view that for our beliefs to be true and justified, in other words for them to count as knowledge, these beliefs must correspond to the way the world is. This means that truth is determined by whether our ideas match up with the way the world is independent of our ideas. This is that view, to use Kant’s language, “objects must be legislative to the activity of knowing.” It is this view, Kant argues, that contributes to both Berkeley’s idealism and Hume’s skepticism. This is because it is impossible to have any idea of how the world is independent of our ideas. Ideas (And, again, remember ideas here are all mental content. Sensations are ideas.) are the means by which the world is presented to us. Thus, although we can have a notion of there being a world that is a certain way independent of our ideas of it, we have no way of knowing how that world is. In a way, this is Locke’s distinction between primary and secondary qualities take to its extreme conclusion. If the way something tastes or the color it has is a product of how we experience it rather than the product of how it actually is, then why is this not the case for how something is shaped? In the Kantian view, because space is a pure intuition, the concept of space is transcendentally real, but we do not know whether things in the world exist in space.

In short, the correspondence model claims that we have knowledge about the world if our ideas of how the world is corresponds to how the world is. However, we can never think beyond our ideas to know how the world is. Therefore, the correspondence model leads either to Berkeley’s idealism, where the world is as we think it to be, or to Hume’s skepticism, where we can have no justifiable notion of how the world is.

So, in the second sentence of the quoted paragraph, Kant says, we should consider the opposite. That is, think about the object of sensibility and understanding existing as they do to the extent that they “conform to” or are determined by our ways of experiencing and understanding them. Things have shape because we think of them as spatial things. Things have identity over time because we think of them as substances. Things are causally related to each other because we use the category of causation to conceive of the relations between them. To again use Kant’s phraseology, activity of knowing becomes legislative for objects. If this is the case, then the objective world is the world as it is structured by the synthetic a priori intuitions of space and the synthetic a prior categories of understanding. Kant calls this his “Copernican revolution.”

The consequence of this that many philosophers have balked at is it makes the objective world not a mind independent world but a reason and concept dependent world. Kant calls these kinds of objects phenomena and the world of these objects, the world that we are aware of and claim to know, the phenomenal world. The world as it exists outside of our ideas is called by Kant the noumenal world. The objects in this world are noumena. We can think about how the noumena might be, but we cannot have experience or knowledge of it.