Immanuel Kant’s Critique of Pure Reason is a towering and original work in the philosophical cannon. Kant’s transcendental idealism is designed to remove skeptical doubts about empirical science that Hume had raised by asserting that space and time are conditions of experiences that are internal to each of us. However, Kant cautions that because space and time are internal intuitions that condition our experience we can never know things in themselves or noumena but only things as they appear to us or phenomena. If we forget this, Kant warns that we will end up in endless philosophical muddles. Central to showing the necessity of transcendental idealism are the antinomies of pure reason, which show that when we try to go beyond the conditioned, that is experience within the bounds of space and time, we come to intractably contradictory positions such as the universe in finite in time and space and the universe is infinite in time and space. Kant wants to use the antinomies to motivate us to accept transcendental idealism, because if we assume a transcendentally realistic view of and think we can reach the things in themselves, we end up in the intellectual mire of the antinomies.