#1 - Developing a Transcendental Philosophy
First layer, distinguishing between two philosophical ideas
From the unpublished introduction to Critique of Judgment (Kant drafted two introductions to the work, only one of which he included in the final publication):
I. On philosophy as a system
If philosophy is the system of rational cognition through concepts, it is already thereby sufficiently distinguished from a critique of pure reason, which, although it contains a philosophical investigation of such cognition, does not belong to such a system as a part, but rather outlines and examines the very idea of it in the first place.
Kant wants to distinguish his critical process from philosophy, so then what do we call this process. This critical process forms philosophy of its own as distinct from metaphysics. For clearer explication, one must look at his metaphysics of natural science, Metaphysical Foundations of Natural Science, and his works on moral philosophy, Groundwork to a Metaphysics of Morals and Metaphysics of Morals. He held his metaphysics texts apart from his his three critiques:
the Critique of Pure Reason, being necessary to a metaphysics of science
the second, the Critique of Practical Reason, necessary to a metaphysics of morality.
and finally, the Critique of Judgment, which is necessary to both science and morality, but which can also be considered separately as its own faculty
Kant says that the very idea of science and morality must be put under a microscope which cannot be done without, in a sense, stepping outside those fields, transcendentally speaking. This examination of our faculties for asking and answering questions about nature and morality are as a necessary precursor philosophy. It is transcendental philosophy.
And as with the first, this third critique, the Critique of Judgment, begins with a dissection of our cognitive structure into separate faculties. The first critique, the Critique of Pure Reason, had as its aim to secure a foundation for speculative cognition, i.e., for understanding nature. Understanding nature requires the capacity to make judgments from fundamental principles and concepts which we apply to what we observe. His focus in that first critique was to lay out those propositions we make about our observations, how we string a statement together with a subject, a predicate, and a connecting verb, and how rational persons can evaluate such propositions for their validity. He was outlining the operational nature of theoretical judgments which gives not only science, but all knowledge from experience, a reliable footing, a reliability based on operational concepts.
Kant’ focus in the Critique of Pure Reason was on this foundation of understanding science, but in that section of the book entitled “Transcendental Dialectic,” he acknowledged the possibility of causes other than the natural. If natural causes are efficient, if they are the mechanical cogs and levers that explain why the chicken crossed the road — because some nerve endings in its muscles caused it leg muscles to contract and extend and its joints to swivel and thus mechanically brought it across the road— one must also consider the chicken’s motivation, its final cause, to obtain a morsel of corn. That which helps us decide on particular courses of action is different from the relatively passive understanding of understanding natural phenomena. This latter process is speculative or theoretical cognition, while the process that helps us decide our actions is referred to as practical cognition. So at the start of this third critique, our topography of the mind includes these two continents.