Here, Kant addresses the point that pure reason is concerned with unconditional things, which are objects and events that are not affected by outside forces. However, in the material or phenomenal world, everything is conditional, depending on some circumstance or external factor. Kant describes this rational conflict as an “unavoidable illusion” (87). Kant acknowledges the contradiction while arguing that pure practical reason ultimately seeks out an unconditioned object, the ”highest good” (88). The goal of all ancient philosophy was to learn about the highest good. For Kant himself, the highest good is not just the object of the free will under moral law, but also the determining ground for the will or how the will decides to act.

Looking back at ancient Greek philosophy, Kant argues that the two major philosophical schools, Stoicism and Epicureanism, both in their own ways linked happiness with virtue. However, Kant finds virtue and happiness to be “extremely heterogenous concepts” (90), which means they are very different and even incompatible ideas.

Subsection 1 Summary: “The Antinomy of Practical Reason”

Because of this innate incompatibility, Kant writes that happiness and virtue together form an antinomy—a pair of concepts that appear to contradict each other.