Western Philosophy and the Becoming of Possibility: 7 Kant and the Limits of Reason: Categories as Construal Conditions

If Descartes restructured possibility around the rational subject, Kant reoriented it around the conditions that make such rationality possible. In the Critique of Pure Reason, he reframed the question of possibility itself: not as what exists independently of thought, but as what can be known, conceived, and construed through the structures of cognition. Possibility became inseparable from the transcendental conditions of experience.

Kant distinguished phenomena — the world as it appears to us — from noumena, the world as it is in itself. The categories of understanding, such as causality, substance, and unity, do not describe things as they exist independently, but rather organise the manifold of experience so that it is intelligible to reason. Possibility is therefore not absolute; it is structured, bounded, and mediated by the very architecture of cognition. To grasp what can happen is to grasp the a priori forms through which experience is shaped.

This construal imposed a systematic order on potentiality. Events are not merely contingent; they are intelligible only insofar as they instantiate relations prescribed by the categories. Space and time, as forms of intuition, condition the very horizon of what can appear. Possibility is therefore co-constituted by the mind: the freedom to conceive, the limits of reason, and the structures that make thought possible are inseparable.

Kant’s innovation was to relativise the Platonic and Aristotelian ideals: universals and essences are no longer simply “out there” or in things themselves. They emerge as conditions of construal, the rules by which rational subjects can discern patterns, causes, and relations. Possibility is bounded not by divine will nor by mechanistic determinism, but by the transcendental framework of cognition.

In this sense, Kant both secures and limits possibility. He safeguards the universality of reason while constraining what can be intelligibly conceived. The result is a profound shift: possibility is no longer merely an external horizon or a faculty of the subject, but a relational structure — the interplay of cognition, categories, and the experienced world.

Kant’s philosophy thus establishes a template for modern epistemology and metaphysics alike: construal itself is conditioned, and the landscape of possibility is defined as much by the structures of understanding as by the objects of thought. The horizon of what can be known and what can be actualised is hence a transcendental architecture, meticulously coded into the very form of reason.