Remarks

Anyone familiar with Immanuel Kant’s famous Critique of Pure Reason (1781), or at least the main argument of that work, will know that it had a cataclysmic effect on metaphysics, a discipline which harkens back to the ancient Greeks. 

Kant’s argument in that work is that all knowledge can be accounted for on the basis of two kinds of cognitions, which he calls a priori and a posteriori cognition. A priori (lit., from before) cognition refers to cognition apart from the data of the senses. An example of such cognition is the tautology, “Every man is a man”. This statement is true regardless of the terms used. It is true in virtue of its form. In contrast, a posteriori (lit., after the fact) cognition refers to cognition from experience. It arises from the immediate data of the senses. An example is the statement, “The sky is blue”. This can only be verified by appeal to experience. We have to see it to know it. 

Kant further subdivides a priori cognitions according to the kinds of propositions that can be formed on their basis. The first are analytic a priori propositions. The above example (“Every man is a man”) is an instance of such a proposition, as also any other tautology. Other examples include, “A bachelor is an unmarried man”, and Kant’s own example, “Every body is extended”. For such examples, our knowledge of the truth of the proposition is immediately given by the terms themselves. Nor does the predicate concept add anything of significance to what is already known and given within the subject predicate. They are either the same (as in a tautology) or the one is contained in some way in the other (as the concept ‘extended’ is contained in the concept ‘body’). 

In contrast, synthetic a priori propositions include a conceptual addition on the part of the predicate concept. For example, Kant famously considered such propositions as “2+3=5”, “A straight line is the shortest distance between two points”, and like mathematical statements, to be both a priori and synthetic. They are a priori for the reason that their justification is given by an understanding of the terms alone. They are consequently cognized a priori, that is, without appeal to experience. They are also synthetic for the reason that the predicate concept in this case adds something meaningful to the subject concept. For example, both “5=2+3” and “5=4+1”, “5=7-2” and so on. For such cases, although 5 is equal to each instance, the concept of 5 is not identical with the diverse instances that equate to 5. Hence, each proposition is synthetic. Similar points may be said for the definition of a line, and other mathematical propositions.

Kant further argues that all such (mathematical) cognitions have their origin in the a priori forms of space and time as having their seat in human cognition, specifically, in the faculty of sensibility. For Kant, akin to the movie The Matrix (1999), the world is a mere construct. The difference is that it is not a construct created by an external agent but a construct of human cognition itself. His argument is that the necessity that governs mathematical statements is grounded in the human subject itself. Mathematics is certain for the reason that it is based on our own forms of cognition.

Kant further identifies a second order of synthetic a priori propositions within the realm of what he calls pure natural cognition, a kind of cognition at ground to sense experience. For such cognition, we are innately endowed with what he calls a priori concepts of understanding. These include such concepts as substance, cause, possibility, reality, negation, and so on. Like the a priori forms of space and time, the a priori concepts serve to ground fundamental and necessary (to us) structures of human experience. These include the categorical nature of experience itself, viz., that each thing is a certain thing, that it has properties, and so on; as also, modality (what is, can be, must be), change and becoming, unity and plurality, and so on. On this ground, we form such statements as, “Substance is enduring” and “For every effect there is a cause”. For Kant, these and similar statements are just as synthetic and yet necessary as mathematical statements. The difference is that the former are grounded in a priori concepts whereas the latter are grounded in a priori forms of space and time. All such statements are in turn part of human cognition.

In contrast, metaphysical statements such as, “The world has a cause”, “The human will is free”, “God exists” and so on, conform to none of the above kinds of cognitions. They are obviously not analytic, since neither tautological nor is the predicate concept contained in the subject concept. They are also not synthetic since they consist neither in mathematical propositions nor in propositions that originate out of pure natural cognition. To the contrary, metaphysical propositions extend beyond natural cognition. Indeed, this is their distinguishing feature. 

It is precisely this distinguishing feature that is the heart of Kant’s issue with metaphysics. As metaphysical propositions do not conform to any of the above listed forms of cognition, and as such propositions also “break” the confines that Kant sets down for cognition, it follows that metaphysical propositions must be fundamentally devoid of epistemic content. Consequently, metaphysical speculation consists in a kind of fallacious reasoning. Metaphysical speculation is akin to searching for a red shirt in the dark. The search is pointless since we can never in principle identify the object that we seek. Hence, Kant concludes that metaphysical inquiry is impossible, and its results consist in nothing more than dialectics and illusion (antinomies, paralogisms, etc.). 

The problem with Kant’s account, however, is that it is itself based on assumption. He presumes the existence of a priori forms of space and time and of concepts of cognition without justification. They serve as unjustified first principles of Kantian thought, akin to the first principles of metaphysics—the very thing which he criticizes and rejects. Still more, the restrictions are artificial, unnecessary, and also conflict with the basic character of experience along with the motivations that govern human inquiry.

Consider by analogy a house with an electrical line.

The house represents the natural world. The electrical line represents the causal nexus that governs our experience of the world. Kant’s view is that nothing certain can be known about the cause of power within the house. It is incorrect to infer a possible extension of the line from the house to a source of power beyond the house. The same applies to the metaphysical conclusion that, since the natural world lacks an explanation for its existence, there must therefore be some cause of existence beyond the natural world that explains it.

Following Kant, the natural world becomes a house with an electrical line that has no real source of power. The metaphysician mistakenly believes that the line actually exists and so traces that line to a source of power lying beyond it. However, no such source exists, since the world is a mere representation of cognition, as it were, an appearance and illusion. Hence, the metaphysician is engaging in dialectics or word-play. But precisely what is dialectical in such reasoning? Is it mere word-play to search for a cause of power, or to turn Kant’s argument on its head, is it word-play to deny even the possibility that such a line really exists?

By inference to best explanation, we might respond that we have more reason to reject Kant’s assumptions and conclusions than to submit to them. An electrical line implies a source of power. If the source of power is not inside the house, then it must lie outside or beyond it. The same applies to the natural world. Either the source of the world’s existence is in the world, or it is not. If it is not, then it must lie in some other source, e.g., God, or some other cause. For sure, we might reject the view that the world is an effect of anything. But such a rejection would itself be based on assumptions arising from a competing metaphysical theory. 

The point is that there is nothing particularly special or fallacious about metaphysical reasoning. It is just another form of human inquiry. As other disciplines, metaphysics forms inferences on the basis of premises drawn from thought and experience. The difference lies in the the scope of its inquiry (or domain of discourse). Metaphysics begins with unrestricted being, with being as being, to cite Aristotle. Since unrestricted being refers to all that which is and can be thought, metaphysics quite naturally (and rightly) extends beyond the domain of the natural world in its reflections. “To be” is not necessarily bound to the limits of human sense experience.

Nor should the metaphysician be censured on this account. If there is an electrical line in the house, there must be a source of power. To argue otherwise is to engage in the kind of thinking which Kant attacks metaphysics for, which is precisely dialectics and illusion.