Pearl asked:

How to understand Kant’s philosophy?

Answer by Tony Fahey

For anyone coming to Kant for the first time, what has to be said is that his philosophy is extremely complex and, for some, notoriously difficult to understand. However, it must also be said, for those who take the time and trouble to work with it, his philosophy both rewarding and beneficial. Taking the view that the questioner, in this instance, really has a genuine interest in the works of Immanuel Kant, I have set out, with particular attention to his Critique of Pure Reason, what I believe are the most salient points of Kant’s philosophy.

Empiricist philosophy argues that there is a connection between the human mind and the outside world: a connection which is made through sense impressions and their impact on the human brain; an impact which is scientifically investigable and understandable. According to the Empiricist view, human knowledge is something ‘out there’: something that is external to the mind. Human beings, says Empiricism, are not entombed within their own minds: ‘mind’ and ‘world’ are not inseparable.

In his An Essay Concerning Human Understanding (1690) John Locke declared that the mind was a tabula rasa – a blank slate. Human beings, he argued, are born with nothing other than the capacity to experience through the senses. The knowledge we acquire is not due to any innate power to reason, but by the accumulation and organisation of experience. David Hume (1711-1776), one of Britain’s most eminent empiricists, followed Locke’s argument. ‘We know the mind’, said Hume, ‘only as we know matter: by perception’. Hume maintained that the mind is not a substance, an organ of ideas, but an abstract name for a series of ideas, memories, and feelings, which all have their source in experience.

The German philosopher Immanuel Kant (1724-1804) was impressed by the Empiricist argument that experience is the basis of knowledge. Indeed, he claimed that reading Hume caused him to awaken him from his ‘dogmatic slumber’. However, he could not accept that all knowledge was derived from experience. ‘Though all our knowledge begins with experience’, he said, ‘it by no means follows that all arises out of it’. In 1781, in response to the claims of Empiricism, Kant published his famous Critique of Pure Reason; his ambition was to show pure reason’s possibility, and to exalt it above the impure knowledge which comes through the channels of sense. By ‘pure reason’ Kant means knowledge that does not come by way of sensory perceptions. There is knowledge, he argued, which, though it may derive from experience, is understood to have its source in other than experience: knowledge that is inherent in the human mind: knowledge which is a priori.

The mind, says Kant, receives data of the phenomenal world through sensory perceptions. However, in order to understand this information these sensory perceptions must be processed by certain conditions inherent in the human mind. As well as the ‘intuitions’ space and time, Kant lists ten categories which were meant to define every possible form of prediction: substance, quantity, quality, relation, place, time, position, possession, action, and passivity. These concepts (or categories) were reorganised to consist of four types: quantity, quality, relation, and modality. In short, everything we, as humans, experience we can be certain will be imposed within the a priori framework of the intuitions space and time, and subject to the law of causality – the law of cause and effect.

The phenomenal world, says Kant, is a combination of something which our senses present to us and a priori conditions inherent in the human mind. The mind, then, determines the kinds of answers given but not the specific content, which only experience can provide. Space and time, and the law of causality, impose on the mind necessary conditions of both experience and knowledge, but the actual content arises out of something independent in us: before sensations can be known they must be brought into a unified consciousness, which thus is no mere additional sense, but an intellectual synthesis, presupposed by every possible experience.

According to Kant, the world, for humans, is not a datum given by some external power. It is not some objective fact ‘out there’; it is a product of the laws of our own understanding, acting in no arbitrary way, but according to specific principles, which are not peculiar to our separate individuality. For Kant human experience gives a point of view for the interpretation of everything that we can know; between the world, and ourselves there is an inner identity. As human beings we have sensory experiences, that is, we perceive impressions of phenomenon from the outside world through the senses; these sensory impressions are thus shaped by conditions inherent in the human mind. In other words, the mind assimilates the information perceived through sensory perceptions, and the conclusions (or, as Kant calls them, judgements, it arrives at will conform to the a priori intuitions of space and time, and the law of cause and effect. They are a priori but they are discovered by experience.

According to Kant there are two sets of elements that contribute to our understanding of our world. The first set involves external conditions, which we cannot know before we have perceived them through the senses. The second involves the conditions inherent in the human mind. Empiricism argues that the human mind is but a ‘passive wax’ which is pummelled and shaped by sensory impressions. David Hume had reduced the mind to little more than a sponge which absorbed impressions and formulated complex ideas, not by virtue of any innate power, but by force of repetition and habit. Kant refused to accept such a skeptical approach. While accepting that our knowledge of the world enters the mind via sensory experience, he rejected the notion that all our knowledge arises out of these experiences. If this is the case, the question arises as to from whence comes order.

Hume had maintained that it was only the force of habit that made us see the causal connection behind all natural processes. Kant refuted this argument: the law of causality, he held, is eternal and absolute: it is an attribute of human reason. Human reason, he said, perceives everything that happens as a matter of cause and effect. That is, Kant’s transcendental philosophy states that the law of causality is inherent in the human mind. He agreed with Hume that we cannot know with certainty what the world is like in itself, but we can know what it is like ‘for me’ – or for all human beings. We can never know things – in -themselves (noumena), said Kant, we can only know them as they appear to us (phenomena). However, before we experience ‘things’ we can know how they will be perceived by the mind – we know a priori.

Thus, for Kant, the mind contains conditions that contribute to our understanding of the world. As well as the law of causality these conditions include the modes of perception, space and time. Space and time, he says, are not concepts, but forms of intuition. Everything we see, hear, touch, smell, and so on, happening in the phenomenal world occurs in space and time. However, we do not know that space and time is part of the phenomenal world; all we know is that they are part of the way in which we perceive the world. Time and space, he says, are irremovable spectacles through which we view the world. They are a priori forms of intuition that shape our sensory experience on the way to being processed into thought. Space and time are innate modes of perception that predetermine the way we think. It cannot be said that space and time exist in things themselves, things ‘out there’ in the world, rather they inherent intuitions through which we perceive and conceive our world. Time and space, says Kant, belong to the human condition. They are first and foremost modes of perception, not attributes of the physical world.

Kant called this approach the Copernican Revolution in the problem of human knowledge. That is, it was just as radically different from earlier thinking as Copernicus’ claim that the earth revolved around the sun.

Drawing from both Empiricism and Rationalism, Kant formed a synthesis between two schools of thought and created his own model. He argued that both sense and reason are integral to our understanding of the world. He accepted Hume’s theory that all our knowledge comes from sensory experience, but he also agreed with the Rationalists that our reason contains certain decisive factors that determine how we see and understand our world. Everything we experience will first and foremost be perceived as phenomena in space and time, and for everything that happens we will want to know the reason for its occurrence: its causality. For Kant these conditions are inherent in our minds: they are a priori, and they are what it is to be a human being.