Kant's First Paralogism

In the chapter of the Critique of Pure Reason entitled “The Paralogisms of Pure Reason” Kant seeks to explain how rationalist philosophers, including thinkers of the caliber of Descartes and Leibniz, could have arrived at what he considers to be certain erroneous, “dogmatic” conclusions about the nature of the self or soul. His diagnosis has two main components: first, the positing of “Transcendental Illusion”—a pervasive intellectual illusion, modeled on perceptual illusion, which predisposes us to accept as sound certain invalid arguments for substantive theses about the nature of the soul; second, the identification of the relevant fallacies. This essay examines Kant's account in the First Paralogism of how these two elements combine to produce the doctrine that the soul is a substance. It is argued that Kant has a novel, ingenious—and even somewhat plausible—account of how the rational psychologist might arrive at such a view. It is further argued that the source of the fallacy in the first paralogism is a confusion about the very nature of conceivability and that, in identifying this confusion, Kant makes a philosophical contribution of lasting value.