Preface
The Prolegomena is a preface to (and summary of) the Critique of Pure Reason. I’ll be publishing a series of posts on these books, as I work through them.
Kant acknowledges in the Prolegomena that he has been roused by Davi Hume from “dogmatic slumber”. Hume argues that concepts such as cause and effect are invalid as they not based on experience, and so the study of metaphysics and philosophy are suspect. Kant, starting from the same premises as Hume, reaches a slightly different conclusion: although they are not based on experience, these a priori concepts are necessary if we are to make sense of the totality of human experience. He also asserts that we cannot know things as they really are in themselves, but only as objects of our experience.
Throughout the book, I find myself constantly disagreeing with Kant, whose arguments seem full of holes and far from convincing. Either I’m completely missing the point — which is quite possible, as this is only the third of his books that I’ve read, or Kant is making a fundamental mistake, that is, drawing universal conclusions about human cognition from his own demonstrably faulty understanding of particulars. Hume, whom Kant hails as an “acute man”, made the same type of mistake.
Glossary
As I understand them, Kant’s notions of a priori vs. a posteriori, analytic and synthetic, can be visualized using the above diagram. I’ll try to explain them in plain english, so to speak, as follows: First, an analytic statement is explicative, it makes clear what is in the concept itself, without reference to any experience of concrete objects. In other words, what is analytically true is true by definition; Second, an a priori statement is a statement that is also without reference to experience, however, it is not necessarily part of the concept by definition, at least not in the way that people normally think of it; Third, a posteriori statement, as opposed to a priori, must involve experience of concrete objects. Fourth, and the most important for Kantian epistemology, a synthetic statement is expansive, that is, it expands our knowledge, which is the proper end of science. A synthetic statement can be either a priori or a posteriori, a priori if it forms a connection between two concepts, which we haven’t connected before, and thus expanding our knowledge (eg. with the aid of visualization), without augmenting our experience, a posteriori, when our knowledge of concrete objects increases through our experience of them, which knowledge cannot be gained any other way.
Objections
First, the difference between analytic and synthetic.
Kant gives as an example of a synthetic statement, 5 + 7 = 12, for although it is a priori and necessarily true, it is not analytic, for people don’t normally think of 12 when they think of 5 and 7, or vice versa. I submit that the statement is analytic, because it is true by definition, that is, all the relations between the numbers have been defined, regardless of whether we can perceive them, and if the principle of contradiction is a true test of an analytic statement, it can be proven that to deny 5+7 = 12 necessarily leads to the contradiction that 12 != 12.
Second, whether space and time are inherent in physical objects.
Kant argues that space and time are a priori condition of our knowledge of the physical world, but space and time are not inherent in the physical objects. To prove this, he argues that we can conceive two objects with identical properties, and replace one with another in our mind, but we treat them as different objects in the physical world due to their external spatial relations, not internal qualities.
The problem with Kant’s argument, as I see it, is that he is begging the question. This problem is most manifest in his example of the mirror image, where he asserts that an object and its mirror image are identical, like one’s right and left hands. But, the difference between the object and its mirror image is precisely that the former has 3-dimensional spatial qualities and the latter had only 2 dimensions. Kant can conclude that they are identical only because he has already (unwittingly) removed the spatial qualities and flattened the objects in his mind. To use an analogy, it is like Kant visualizes a person in his mind, with all the qualities of the real person, except that s/he doesn’t breathe, and then concludes that breath is not an inherent property of the person, simply by visualizing the same (breathless) individual in the real world.
Third, whether knowledge of things as they are in themselves is possible.
To prove or disprove whether knowledge of anything is possible, a philosophical approach would be to: first, define what one means by “knowledge” and “knowing”, second, enumerate all the possible ways of knowing, third, only then can one proceed to show whether the specific type knowledge in question is possible.
Kant does not do that. Instead, he assumes/asserts that knowledge is possible only through sensuous experience, and since the substance of things cannot be accessed by the senses, we cannot know things as they are in themselves. So it follows, according to Kant, we cannot know ourselves as we are in ourselves. And yet, he is inconsistent in this regard, for he also asserts that we have freedom as we are in ourselves. He doesn’t explain how he comes to that knowledge of freedom, which is not an object of the senses, or why, if it is possible to know one attribute of ourselves, it is impossible to know others in the same way.
I have a sneaking suspicion that Kant’s response to Hume is an act of self-defence, or to borrow his own word, a “rescue” mission. In a rescue mission, one is forced to rescue what he cares about the most, and forgo the rest. Hume has launched an attack on metaphysics, in particular, moral philosophy and theology. Kant made a vigorous attempt to defend moral philosophy, but left theology to fend for itself, if not threw it under the bus.
Related Posts
References:
- Kant, Immanuel. Kant’s Prolegomena to Any Future Metaphysics. Translated by Paul Carus. Open Court Pub. Co.: Chicago, 1902.