Visualizing Kant's Philosophical System
This page features visualizations of the relationships between (some of) Kant's critical works/parts of his philosophy.
Here we can see the relationship between Kant's main critical works. The Prolegomena to any Future Metaphysics is directly dependent on the first Critique of Pure Reason, as it gives the overview of this latter's systematic structure. The first Critique gives the fundamental principles of theoretical or speculative reason. This work legitimizes the possibility of metaphysics and articulates the fundamental principles of a critical general metaphysics. When we apply these principles to the concept of <matter> or <body> as the moveable in space, this generates a system of special metaphysics of matter applying to bodies as such, which are treated in the Metaphysical Foundations of Natural Science, which articulate a rational foundation for Newtonian physics (that does not rely, as Newton's own natural philosophy did on epistemically problematic concepts of Absolute Space and Time inherently tied to a particular concept of God) that is directly dependent on the first Critique.
The Groundwork of the Metaphysics of Morals has as its main aim to establish and legitimize the possibility of the supreme principle of morality (the categorical imperative). Thus, it is not directly dependent on the first Critique, but this latter work can help legitimize the former's appeal (in its third section) to the distinction between things in themselves and things as they appear in the face of potential objectsion. Similarly, the second Critique of Practical Reason articulates the fundamental principles of practical reason and demonstrates the practical reality of freedom. It does not directly depend on the Groundwork, but this latter work can defend the second Critique in the face of challenges to the very possibility of morality and so indirectly supports the former. When we apply the principles of practical reason and morality to the concept of <human> as finite rational beings, this yields the Metaphysics of Morals, which constitutes both a system of moral rights and ethical duties applying to humans as such in the form of the Doctrine of Right and Doctrine of Virtue. These moral and ethical systems are directly dependent on the Groundwork and second Critique.
The metaphysics of nature and morals respectively provide the rational foundations for the empirical study of physics and ethics (the latter in the form of a practical anthropology) given rich and variable empirical details of particular bodies and humans.
The third Critique of the Power of Judgment seeks to harmonize the twofold metaphysics of morals and nature and thus harmonizes the systems of the Metaphysical Foundations and the Metaphysics of Morals, thereby vindicating the possibility of humans' realizing morality in material nature.
All the work of the three Critiques and the main works articulating the twofold metaphysics of nature and morals make possible the work of the Religion within the Limits of Reason Alone, which gives the principles to build a universal ethical church/community on Earth, which only depends on rational, moral, and ethical principles inherent in the essential structure of the reason common to all, and has as its goal the cultivation of moral virtue.
With the relations between these main works, spelled out, the next diagram adds relations of indirect dependence with dotted lines. These indicate when the achievements/resources of one work are required in some crucial way for the arguments/achievements of another.
Note the crucial foundational role that the first Critique plays in particular, as well as how the three Critiques serve as anchors in the philosophical network of Kant's corpus.
The works with dashed outlines play a foundational role, while those with dotted outlines are less secure parts of the corpus either because they were not published in Kant's lifetime (as in the case of Progress in Metaphysics) or because the manuscript was not prepared by Kant himself (as in the case of the Logic, edited by Jäsche, a former student of Kant's at the latter's request).
Another notable addition in this third diagram is the (practical) Anthropology, which deals with what the human being should make of themselves given their constitution. This work thus deals with ethical conduct when considering the rich and variable empirical details of individual humans in particular circumstances. This work is analogous to the empirical study of Newtonian physics built on the foundations of the Metaphysical Foundations and is accordingly directly dependent on the Metaphysics of Morals (though it also draws on the resources of the first and third Critiques, which articulate the constitution of our cognitive capacities). Note that Kant himself did not write a text dealing directly with empirical physics, so it's not included.