Apodictic certitude!

 

“All our knowledge begins with the senses, proceeds then to the understanding, and ends with reason. There is nothing higher than reason.”

― immanuel kant, Critique of Pure Reason

Immanuel Kant (1724–1804) is the central figure in modern philosophy. He synthesized early modern rationalism and empiricism. The fundamental idea of Kant’s “critical philosophy” – especially in his three Critiques: the Critique of Pure Reason (1781, 1787), the Critique of Practical Reason (1788), and the Critique of the Power of Judgment (1790) – is human autonomy. He argues that the human understanding is the source of the general laws of nature that structure all our experience; and that human reason gives itself the moral law, which is our basis for belief in God, freedom, and immortality. 

The great idea of the Critique of Pure Reason is  the very thing that explains the possibility of 

our knowledge of the fundamental principles grounding a scientific view of nature is also the key to the possibility of our freedom in both intention and action, which seems threatened by the rule of causality in that natural world. Kant argues that the principles of the scientific worldview can be known with certainty because they express the structure of our own thought. They are therefore conditions of the possibility of our experience, which we impose upon the raw data of sensation. Thus, there is a sense in which certitude about the principles of science is possible only because of human autonomy: we are not merely passive perceivers of sensible information flowing into us from external objects, but also cognitive agents who structure what we perceive in accordance with the necessary conditions of our active thought. Thus Kant argues that we can be certain of the fundamental principles of science - above all the universal law of causation, the assumption underlying all scientific inquiry that every event has a cause and can therefore be explained in accordance with a law of nature - precisely because this law is a condition of the possibility of the thought that we must impose upon our perceptions in order to have any experience at all.

Kant defines the position of critical philosophy in contrast to dogmatism, empiricism, skepticism, and indifferentism. He seeks to carve out for theoretical philosophy a significant but limited domain, distinct from that of empirical knowledge and the opinions of common sense, but excluding the exaggerated claims that have brought metaphysics into disrepute. In this way, the Critique of Pure Reason belongs to a main tradition in modern philosophy, beginning with Descartes, that tries to provide an a priori philosophical foundation for the methods and broad features of a modern scientific view of nature by an examination of the suitability of human cognitive faculties for the kind of knowledge of nature that modern science aims to achieve.

 At the same time, Kant tries to save precisely what the dogmatic metaphysicians cannot, by connecting the claims of religious metaphysics not to the sphere of theory but to the sphere of moral practice, and, in the famous words of the second-edition preface, by limiting knowledge in order to make room for faith (BXXX). But Kant tries to accomplish all these goals, especially the last, in an authentically Enlightenment manner, always giving first place to our rational capacity to reflect on our cognitive abilities and achievements, to correct them, and to subject the pretensions of reason to self-limitation, so that human reason itself retains ultimate authority over all matters of human knowledge, belief, and action. The ultimate autonomy of human thought lies in the fact that it neither can nor must answer to any authority outside itself.