Arguably Germany's best known intellectual maverick, Immanuel Kant presented an unconventional frameworks of thought that shook the foundations of epistemology and ethics, though the philosopher made several noteworthy contributions to metaphysics and aesthetics as well. His predecessors shaped philosophy into a discipline of black and white, one could either be a Rationalist or an Empiricist. The Rationalists believed that the mind had inbuilt notions of individuality, self and morality which aided human beings in processing information that was encountered. Empiricists countered such claims with ideas that the mind was a blank slate upon birth, and that true knowledge could only be gained through sensory experience. Heated debates on the source and nature of true knowledge occupied philosophers for centuries prior to Kant. Philosophers who partook in this debate traditionally aligned themselves to one side or the other.
The novelty with Kant was his creation of a perspective that was an amalgamation of both Rational and Empirical principles, as he believed that a position that occupied either extreme end of the spectrum was inherently flawed. While he agreed with the Rationalists that the mind had certain inbuilt structures of perception, he found too many internal contradictions amongst the philosophers who held this view. Similarly, he agreed with the Empiricists that experience extended knowledge and was therefore an important source to learn from, he thought the "tabula rasa" or blank slate argument was flawed. The explanation for this refutation was that babies have inborn notions of space and time. A baby learning to crawl realizes that he has to move in order to get from point A to point B. But, this realization is contingent upon his understanding of the space between the objects, the conception of which he is born with. In Kant's famous book "The Critique of Pure Reason" (1781) he proposes his famous transcendental idealism argument. A transcendental argument simply proposes that certain factors must be held good in order for others to play out in different variations. He proposed that the mind held certain categories into which all empirical knowledge was classified. An analogy to understand this framework is the mind as a machine, with four different boxes. As soon it receives any form of input, it immediately sends it to the box where it would best fit. If these boxes did not exist, all inputs would have no meaning at all, as we could not understand them in context of the box. The four categories proposed by Kant were quantity, quality, relation and modality. Each presupposes the experiences one encounters in the world, and enables the mind to process and derive knowledge from them.
Another significant feature of The Critique of Pure Reason was the novel proposition of synthetic apriori knowledge. Knowledge had 2 manners of being classified. The preliminary classification was apriori or aposteriori/empirical knowledge. Apriori knowledge can be known without any form of experience. Aposteriori or empirical knowledge has to be experienced with the senses to be verified. The second method of classification is the division between synthetic and analytic propositions. Analytic propositions are true by definition. For instance, ' the pigeon is a bird' is analytic, as the predicate is already contained in the subject. A pigeon, by definition, is already a bird. A syntethic claim extend one's knowledge, because the predicate of the sentence is not contained in the subject. The sentence 'the pigeon is injured' is syntethic, as nothing about the subject's properties indicate injury by default. Therefore, syntethic claims are ampliative, and help knowledge grow. By logic, apriori claims were thought to be analytic, as anything that is known without experience is true by definition. Likewise, aposteriori claims are synthetic, as it is only through experience that knowledge can be extended beyond what we already know through definitions. Kant proposed synthetic apriori knowledge. The immediate logical conclusion would suggest this type of knowledge is impossible. However, Kant makes a case using simple math. The proposition 'the triangle contains interior angles equal to 180 degrees' is naturally true. However, there is nothing in the subject to suggest that the predicate is true. Yet, this fact that interior angles will be equal to 180 degrees can be empirically verified with ease. Such syntethic apriori knowledge is both true and ampliative, which is why Kant propagated it with vigor.
Kant's unconventional approach extended to moral philosophy as well. The philosophers of the past had taken a largely consequentialist view of morality, that the morality or immorality of an action must be judged by its consequences. To Kant, humans were rational beings who had the mental acumen and free will to make the right choice, and not only take the right action, but to do so for the right reason. Free will is an integral part of Kantian ethics. An important distinction is made between free will and physical necessity. Physical necessity dictates that it is morally sound for an animal to murder another, as it would starve if not for the prey. Free will, however, is free of such physical necessity. The freedom is a property which enables one to act independent of outside causation and pressures. While it is natural that external pressures will exist, Kant notes that what differentiates man from animal is the ability of man to rise above his primal needs and pressures and exercise his free will to do so and act in a way that is morally correct. In order to be truly moral, Kant believes one must act in accordance to a categorical imperative, which he details in his book "Groundwork of the Metaphysics of Morals" (1785) Normally, we act with a hypothetical imperative in mind. We believe that if we choose to do the right thing, it will earn us praise or rewards. Here, we act morally for the sake of some end. The categorical imperative implies acting in such a way that we act in the correct manner purely because it is the right thing to do, and we have a duty to do so.
In order to check if an action is in true accordance with the categorical imperative, Kant provides two conditions to be fulfilled. Firstly, the maxim must be universalized. For instance, if a person cheats on a test because they do not want to fail and worry their parents, they are incorrect becuase if they take the act of cheating out of this context and into any other, it would be immoral. Secondly, Kant believes in treating people as ends in themselves and not as means. For instance, lying to one's dying mother about the severity of her condition is not correct, because we are disrespecting her agency as a rational human, and using her ignorance of her condition to prevent her from realizing the truth. This ethical framework is rooted in logic, in sharp contrast to several religious frameworks, which dictate actions and consequent punishments in order to keep persons in order.
