Summary: Critique of Pure Reason (page 4)

This is significant because, until then, metaphysics had been regarded—at least within the Scholastic tradition—as the queen of the sciences. The supposed superiority of its subject matter (God, and so on) had led to the belief in the superiority of its results.

With Kant, however, metaphysics is expelled from the domain of knowledge altogether and no longer qualifies as a science in any sense—a position that would be adopted by all modern thinkers. Its objects (God, immortality, and so on) are relegated to the realm of belief and theology.

We are now in a position to understand the title of the work. This requires grasping another Kantian distinction: that between the understanding, which merely analyses the data of experience, and Reason—the higher faculty of the mind that naturally rises above experience and forges Ideas (such as God), which it then mistakenly takes as objects of knowledge.

As we have seen, pure refers to the notion of a priori. A metaphysical system consists of a set of a priori (or pure) judgements, since such judgements cannot be grounded in experience.

Pure reason, then, is that power of the mind which leads us to metaphysical thought.

The task is to undertake its critique—that is, to demonstrate that this faculty of the mind cannot yield genuine knowledge.

We can now understand what Kant means by Critique of Pure Reason. The title of the work is fully explained.

Let us now turn to the first Preface and explore a text that should by now appear considerably clearer.

Kant begins by describing the predicament of reason: its tendency to ask metaphysical questions that can never be resolved, as they exceed the limits of human reason, since they go beyond any possible empirical use ¹.

For example: Does God exist? Is there a first cause, or does the chain of causes and effects extend infinitely? Are we free? And so on.

These questions are insoluble, yet this does not prevent the mind from asking them. On the contrary, it gives rise to endless conflicts—the battles of metaphysical systems (those of Plato, Leibniz, Spinoza, and so on):

The battlefield upon which these ceaseless conflicts unfold is called Metaphysics.

These systems were dogmatic, as they could not prove the truth of the first principles upon which they rested. As a result, scepticism spread—not only against these systems, but against the very possibility of knowledge itself.

Yet one cannot simply remain indifferent to these metaphysical questions. It matters to everyone to know whether they are truly free, or whether there is life after death.

It is therefore necessary to establish a tribunal that can, as we have seen, guarantee reason in its legitimate claims, while at the same time rejecting its unfounded pretensions—in other words, to determine which propositions belong to well-founded knowledge and which belong to mere belief.

This is the origin of Kant's project: this tribunal is none other than the Critique of Pure Reason.

This is, by its very nature, a humble project, seeking to identify the limits of reason. It stands in opposition to the pretensions of dogmatism—the pride of the metaphysician who claims to extend human knowledge beyond all possible limits of experience, asserting, for instance, the demonstrable simplicity of the soul or the necessity of a first beginning of the world.

The central question of the work, let us recall, remains:

What can the understanding and reason know, and to what extent can they know, independently of all experience?

Here, we must recognise that the mind is about to take itself as its own object of study—the understanding will examine its own workings. And it is precisely this that will guarantee the certainty of the results obtained.

Indeed, if reason examines itself, then in order to attain a detailed knowledge of it, I need not search far and wide, since I encounter it within myself.

Or, to put it differently: Nothing here can escape us, for what reason produces entirely from within itself cannot remain hidden.

¹ Our translation. The references for the quotations are available in the book Kant: A Close Reading