Immanuel Kant
(1724 – 1804)
German philosopher, one of the most influential Western philosophers. He developed the doctrine of transcendental idealism, which he wrote into comprehensive systems in epistemology, metaphysics, ethics and aesthetics.
His most important and famous work is the Critique of Pure Reason (1781). Kant wrote the work as a response to Hume’s scepticism (see Hume on causality). In order to solve the attack on rationalism made by Hume, Kant had to show that there is such a thing as synthetic a priori truths, that is, meaningful statements about reality whose truth is known independently from observation.
Kant uses the method of transcendental deduction – he goes beyond (transcends) direct observation and sense experience, and tries to go underneath the mind, to understand what are the necessary conditions for perception, and what are the mind’s innate modes of processing sense data. In his analysis, Kant divides the mind into three faculties:
(1) Intuition (i.e. Perception) – Kant asks: how is perception possible? If we take the common- sensical view that we do perceive the world, he asks what conditions must hold for that to be possible.
—> He shows that space and time are synthetic a priori foundations of perception. Space and time do not exist as such in reality, but they are internal structures (faculties) of the human mind that shape the way we perceive reality (the human mind analyses sense data it receives in terms of space and time)
(2) Understanding – the faculty that enables us to understand facts about the world. Common- sense dictates that we do have knowledge of the world and Kant asks how such knowledge is possible.
—> He shows that knowledge of the world is grounded in synthetic a priori foundations of the faculty of understanding, which he calls the categories of understanding.
These are: unity/plurality/totality; causality and substantiality. These concepts are not deduced by the mind from reality, but the mind projects them onto reality.
—> As opposed to previous rationalists, Kant does not claim that we are born with some innate ideas, but rather; that the mind is structured in such a way that it analyses sense data it receives in terms of a particular set of a priori synthetic rules – the mind is programmed to understand the world in terms of the categories of space/time/causality/substantiality, but these don’t actually exist in the world.
(3) Reason – the faculty that produces pure concepts such as God, soul goodness, immortality, freedom, etc.
—> This gives rise to another important distinction in Kant’s philosophy:
phenomenal world – the world as it is perceived, interpreted, analyzed, imagined and theorised by the human mind
noumenal world – the thing-in-itself, the reality behind appearances, higher truths and concepts produced by Reason.
Kant’s conclusion is that common sense and science are valid, but only insofar as their claims are about the phenomenal world. So contrary to Hume, it is possible to have real, practical knowledge of the world. However, nothing positive can be said about the noumenal world, other than that it exists. We simply cannot know (nor can ever dream of knowing) God, soul, justice, immortality or freedom, because all these ideas overreach the human capacity for knowledge.
However, according to Kant, we have a right to believe in these ideas, not out of a metaphysical necessity, but as practical (ie. moral) necessities. Furthermore, Kant pointed out certain human experiences and intuitions that give some hints of the noumenal world – for example, the feeling of sublimity that we experience when we are high on top of a mountain looking down, or the inspiring feeling of moral duty in certain moments of our lives.
Kant also importantly contributed to ethics. He developed his moral philosophy in the Groundwork of the Metaphysic of Morals (1785) and the Critique of Practical Reason (1788). His most important idea is the formulation of the moral principle called the categorical imperative.
– The categorical imperative states that one should “act only according to that maxim by which you can at the same time will that it should become a universal law.”
– This means that all moral acts should be modeled on principles that can be universalized without contradiction. You cannot make exceptions for yourself and you can only allow yourself actions that could become a universal law (that everybody would act in this way).
– For example: I cannot permit myself to lie, no matter the circumstances, because if I do, I make lying into an acceptable universal act. If everybody lied, the world and society would come to a confusing halt. Lying then, cannot be universalized, because the world would come to a contradiction if it was. Hence, lying is always wrong.
– Because the morality of an act is judged by the motives of an action, the categorical imperative is deontological (cf. Bentham’s consequentialism)