As mentioned in the last blog, David Hume created a critical empirical philosophy that was ultimately skeptical in its conclusions. If you remember, David Hume took the position that all we really “know” are successive sense impressions. Taken literally, this undermined in Hume’s eyes the reality of the human person, the reality universal concepts, causality, and other ideas central to modern science.
Immanuel Kant (1724–1804) credits reading Hume with “awakening him from his dogmatic slumbers”, leading to the creation of the most important work of continental philosophy of the late 18th century. Kant’s thinking continued to influence philosophy through the 19th and 20th centuries and until today. After reading Hume, Kant set out to reestablish a ground for human knowledge, religion, science and morals in light of Hume’s critique.
Kant’s Structure for Philosophy
Kant adopts the Greek division of philosophy (the love of wisdom) into three categories:
- Physics (natural philosophy),
- Ethics (the study of what humans make of their freedom) and
- Logic (the study of formal logical systems, such as mathematics and formal logic).
Logic has no empirical component and so can arrive at analytical a priori certainty, but both natural philosophy and ethics have empirical components and so operate differently. 
One writer describes Kant’s position as follows:
Like Locke and Hume, Kant thinks we must realize that the boundaries of human knowledge stop at experience, and thus that we must be extraordinarily circumspect concerning any claim made about what reality is like independent of all human experience. But, like Descartes and Leibniz, Kant thinks that central parts of human knowledge nevertheless exhibit characteristics of necessity and universality, and that, contrary to Hume’s skeptical arguments, we can have good reason to think that they do. 
Kant’s Categories of Knowledge
Kant’s first philosophical move was to agree with Hume that all of real, positive knowledge of reality flows from experience. Kant’s second move, however, was to establish his position that reason forms this knowledge according to certain a priori categories, such as time, space and causality. These categories are not aspects of reality but aspects of the way in which human beings organize human knowledge. For example, the language of pure mathematics is analytically prior to all experience. Time, space, and causality, they are synthetic (or empirical) a priori categories of human thinking.
Before going forward, I want to look more deeply into Kant’s notion that time, space and causation are facets of the human mind, a priori ways in which experience is structured. Interestingly, this analysis will help understand his political philosophy and its weaknesses. Quantum physics and relativity theory cast doubt upon Kant’s ideas as regards time, space, and causality. Time and space are not eternal ideas in the mind of God or human mind, they are relative features of the universe dependent upon one another for their determination. In the case of causality, one of the features of quantum physics is the breakdown of the Newtonian, common sense, everyday notion of causality in the subatomic realm. Our ideas of time, space, and causality, as important as they are, are relative features of the physical universe that we have uncovered to make sense of a variety of human experiences. They do not appear to be inevitable features of the human organization of experience. 
Kant also operates within the boundaries set by Descartes division between subject and object, the universe and the human knower. Quantum physics does not favor this approach, since it is a feature of quantum physics that the observer cannot be totally removed from his or her observations, in fact the observer determines to some degree the outcome of their observations. Quantum physics and Relativity theory would seem to favor a view of the human mind (observer) as part of the observed (the universe).
These observations lead to quite different conclusions from the stark division of Kant between what is a priori in the human mind and synthetic aspects of human experience. The human mind is part of the reality it is observing, and structures its thought around aspects of reality that have emerged in human history as important to understand the reality of which the human actor is both an observer and a part of the unfolding reality itself. This participation of the observer in what is observed is a feature of all human experience, including moral and religious reasoning.
As to ethics, Kant also believed that we have moral knowledge independent of experience, that is a priori. This was not analytic a priori, such as mathematics, but synthetic a priori. His categorical imperative is one such a priori kind of knowledge. For Kant, the fundamental moral principle, the categorical imperative requires human beings to act as if the action that they are contemplating could be universalized. In his Groundwork for the Metaphysics of Morals, Kant specifies the imperative as follows:
Act only in accordance with that maxim through which you can at the same time will that it would become a universal law. 
It goes without saying that Kant might be in error concerning just how, a priori this statement might be. It is found in the form of the Golden Rule in Christian faith and in other religions as well. It seems to be a part of that moral wisdom that human beings have intuited based upon the lives of generations of human beings, not an a priori aspect of the human mind. It is more as likely that this principle is not a synthetic a priori, a creature of the human mind, but a principle, like E=MC2, that human beings have abstracted from human experience and regularities humans have noted in observing the inverse. In other words, morals are not solely internal to the human subject but features human beings have abstracted from a moral and ethical reality they experience and of which they are inevitably a part. In other words, the foundation of moral reasoning is not a priori rules, but rules of behavior which synthesize historic human experience as found in many traditions.
Foundations of Kant’s Political Philosophy
Freedom and Determinism. For Kant, political philosophy is a part of moral philosophy, which means that it operates with both an a priori and empirical (synthetic) component. This implies that Kant’s political philosophy is conditioned and directed by the early Enlightenment division between mind and matter and the radical schism between subject and object. As we shall see, this division impacts Kant’s political philosophy in fundamental ways.
For Kant, science is the realm of the determined while morals and politics are realms of human freedom. As material creatures, human beings seek their own best interests in a kind of constant economic and political warfare, but as moral beings, human beings seek to fulfill the demands of the moral law—to act according to universal moral principles intuited not from experience but from innate features of human thinking. These two forces (deterministic struggle and moral freedom) operate in tandem in human history, driving human history and the evolution of human societies. Interestingly, Kant does not see these two forces as necessarily opposed to one another. The forces are driving the human race towards peace, harmony and a better world. 
At this point, I return to the observation made earlier that Kant’s acceptance of a division between mind and matter leads him to divide the a priori and the synthetic and a similar division between determined economic forces and human freedom. It is more likely that there is an interplay between the moral, physical and other forces in human history than some kind of tandem coordinated operation. This is more in line with the thinking of C.S. Pierce than with the ideas of Kant.
In my view just as the quantum level of physical reality is characterized by freedom as well as the operation of scientific laws, so also in the realm of politics all decisions and all forms represent the free acts of human beings within the limitations of the laws of the physical universe, choices that may lead for good or evil. In other words, there is no universal movement towards a better future separate from human choices that create such a world.
The Unfolding of Universal History. In 1784, Kant published a work entitled, “The Natural Principles of the Unfolding of the Political Order Considered in Connection with the Idea of a Universal Cosmopolitan History”.  This essay is important as it sets out a line of thinking that eventually emerges as a materialistic idea of the unfolding of history found in Marx. Kant theorizes that the forces of human history seen as the actions of the human will unfold in a deterministic pattern. Kant sets out his thesis as follows:
Considering that men, taken collectively as a body, do not proceed, like brute animals, under the law of an instinct, nor yet again, like rational cosmopolites, under the law of a preconcerted plan, one might imagine that no systematic history of their actions (such, for instance, as the history of bees or beavers) could be possible. At the sight of the actions of man displayed on the great stage of the world, it is impossible to escape a certain degree of disgust: with all the occasional indications of wisdom scattered here and there, we cannot but perceive the whole sum of these actions to be a web of folly, childish vanity, and often even of the idlest wickedness and spirit of destruction. Hence, at last, one is puzzled to know what judgment to form of our species, so conceited of its high advantages. In such a perplexity there is no resource for the philosopher but this,—that, finding it impossible to presume in the human race any rational purpose of its own, he must endeavour to detect some natural purpose in such a senseless current of human actions; by means of which a history of creatures that pursue no plan of their own may yet admit a systematic form as the history of creatures that are blindly pursuing a plan of nature. 
Kant unpacks his thesis noting that while human actions are free, these actions are guided by “nature” to a predetermined social end, the formation of a “universal civil society of all human beings founded on the idea of political justice.” In this line of thinking, Kant, whether consciously or unconsciously, laid the foundation for the kind of Marxist Millennialism that was found so destructive in the 20th Centuries, and which evolved not into a “universal civil society of all human beings founded on the idea of political justice,” but into a kind of intolerable dictatorships that in its current forms look much like Nazism—a union of wealth and government in all-encompassing, dictatorial oligarchy.
Originally, I had intended to spend only one week on Kant and move to Hegel before returning to the American Constitution, but Kant is too complex and rich for such a plan. Next week, I will return to Kant as an interpreter and admirer of Rousseau, and look at the way in which the Romantic ideas of Rousseau influenced his political philosophy. For this week, I want to leave readers with the understanding that, at just the time that America was formed, the Enlightenment was entering a new period—a period that would produce Darwin, Marx, and others, whose thought is not sympathetic to the American constitutional project or free human societies. Perhaps more fundamentally, cracks were forming in the optimistic, progress expecting, human centered foundations of the Enlightenment project, cracks that continue to grow. By the early to mid-20th Century, the foundations of the Enlightenment had completely eroded and human history was entering the period in which we know live, often referred to as “post-modernity.”
 Kant begins his Groundwork for the Metaphysics of Morals by explicating this division and its fundamental importance. Immanuel Kant, Groundwork for the Metaphysics of Morals tr. Allen W. Wood (New Haven: Yale University Press, 2002), 3-4.
 “Kant on the Synthetic A Priori” (August 21, 2018). https://phil871.colinmclear.net/notes/kant-on-synthetic-a-priori/ (Downloaded September 17, 2021)/).
 See, Werner Heisenberg, Physics and Philosophy: The Revolution in Modern Science (New York, NY: Harper Perennial, 1958), 60-66. Importantly, Heisenberg concludes that, “no physicist would be willing to follo Kant here if the term “a priori” is used in the absolute sense given to it by Kant.” Id, at 62.
 Kant, Groundwork, at 37.
 I would just note that it would take a pretty big optimist to see in the current unfolding of the polities of the East and West anything like inevitable progress, which is one of the reasons many thinkers view the Enlightenment project as now clearly failed.
 Seem Immanuel Kant, “The Natural Principles of the Unfolding of the Political Order Considered in Connection with the Idea of a Universal Cosmopolitan History” https://en.wikisource.org/wiki/Idea_of_a_Universal_History_on_a_Cosmopolitical_Plan (Downloaded September 21, 2021).