This chapter explains human knowledge according to Immanuel Kant's transcendental method. Kant, whilst advocating the use of the Ideas as regulative principles, particularly emphasises that teleology should on no account be allowed to endanger proper scientific investigation. The Idea of the soul will guide the connection of all psychological phenomena; the Ideas in Cosmology will aid in discovering the laws of nature; and the Idea of a Supreme Being, as the ground of all possible experience, will help to organise entire knowledge. The idea that systematic unity is manifested in nature is always pursued with much ardour by its investigators, who, led on by the transcendental idea of reason, presume that nature is fundamentally unified, no matter how many practical disappointments they meet. Some students of nature are intent on the idea of the unity of nature, and are continually seeking to discover likeness in diversity.