How We Know: Transcendental Idealism

Previously, I explained the way in which David Hume’s problem of induction entirely undermines any notion of cause and effect in the external world (if you missed part 1 or part 2 of this series, click the hyperlinks). In this part, I’ll be taking a look at a potential solution to this pernicious problem, Immanuel Kant’s transcendental idealism.

To start off, conceptualizing Kant’s ideas is made much easier by comparing them to heliocentrism. Polish astronomer Nicolaus Copernicus, one of the first to espouse this concept, argued that our perception of the sun’s “movement” is really just a facet of our location. Since we are observing the sun from earth, from our perspective as observers, the sun “moves” around us. As this movement is not something actually happening to the sun (the object); it is a condition of us (the subject) and is therefore subjective. As a result, taking the view of Copernicus, the sun’s “movement” is our attempt to fit the sun, as the object of our perception, into our subjective positions. In a similar manner, Kant argues that the subjects of perception are always fitting the objects of their perceptions into their own individual modes of cognition. With this, Kant agrees with the skeptic that we will never know the objective quality of our external world; however, this idea allows us to have knowledge of the only aspects of external objects that really matter to us, their appearance within our own modes of cognition.

The next major step of Kant’s argument is that space and time are a priori intuitions. This is a combination of two technical terms in philosophy. First, a priori is roughly translated from Latin as “from before” and is used to describe knowledge that can be justified without actually experiencing something. For example, mathematics can be a priori because we don’t need to experience the result of adding 3481 objects to 519 other objects to know that 3481 + 519 = 4000. In contrast, a posteriori translates as “from after” and is used to describe knowledge which must be justified by experiencing something. Second, intuitions within Kant’s work refer to the sensory data we can use to perceive objects through experience. This is distinct from Kant’s use of the word concepts, which refer to the representations which subjects can use to think about different objects and understand their qualities.

Kant details six reasons for space being an a priori intuition, but since that takes a lot of space to explain I’ll simply highlight two of the more interesting and important arguments. One of these arguments is that we must be able to know space without experiencing it because space is a necessary pre-requisite for any experience of the external world. In order to conceptualize any object as external to ourselves, we must first understand the spatial relationship between ourselves and the object. Thus, knowledge of the form of space is presupposed for any experience to be possible. This means space must be a priori. One of Kant’s arguments concluding that space is an intuition has to deal with the concept of incongruent counterparts. The clearest example of this is the distinction between the left and right hands. If we attempt to define the hands solely through the spatial relationships amongst their parts, the left and right hands are identical. The components of each hand have the exact same relationships and placements. However, the left and right hands are clearly distinguishable. We cannot represent their distinction through concepts (e.g. by examining the relationship between their parts), so incongruent counterparts in external objects only makes sense is space is conceived of as an intuition instead of a concept. Kant also makes a number of arguments placing time within the category of a priori intuition, and the ultimate aim of these arguments concerning space and time is to establish that these ideas are pre-structured within the human mode of cognition, and this structure is one of the necessary conditions for experiencing anything of the external world. This is the way we know that the mind contains a structure to which experience itself can be made to conform. As a result, the objects we interact with in the external world are the ones which fit within the a priori mental structures of space and time.

The ideas of mental activity presented by Immanuel Kant outline several different faculties of cognition and even find use for the scary-looking combination of words that is the “transcendental unity of apperception”. However, these concepts, while very interesting and imperative in establishing the broader parts of Kant’s transcendental idealism, are not immediately necessary in resolving Hume’s problem of induction, so I’ll be explaining these in later posts.

The next of Kant’s concepts which resolve Hume’s problem are the analogies of experience. Specifically, the second analogy of experience deals with determining cause and effect from the external world. It begins with the idea that every event must have a cause. Kant argues that we can determine causality by seeing whether change occurs as a facet of the object; this is objective change. Objective change must be necessary and irreversible. To explain this, Kant provides an example. If someone walks around a house in a counterclockwise direction, the different representations of the house that the subject sees could have been reversed if he or she had walked around the house in a clockwise direction instead. The succession of appearances would be very different even though the object being observed would remain the same. This change in the appearance of the house achieved by walking around it is neither necessary nor irreversible, so it is not objective. Another example is that of a subject obseving a ship moving downstream. In this situation, the succession of changing appearances could not be reversed because the subject would then be watching the ship move upstream, a different event. This change is necessary and irreversible, and by using this rule, we are able to determine a necessary relationship between events through our senses. This means that our senses (the roots of induction) can determine cause and effect. A similar rule about reversibility is used by Kant in the third analogy of experience to establish a rule distinguishing the coexistence of objects from causal relationship, and thus, Hume’s problem of induction is defeated.

With space and time as a priori intuitions, the human mind has a pre-structured mode of cognition to which all of our experiences conform. This means we can know important aspects of objects. Building upon this idea, Kant outlines the analogies of experience which prove that by using logical rules, we can use our senses to determine necessary relationships between objects. If we can determine those relationships, then cause and effect (a necessary relationship between objects) is most certainly something that we can know.

It took Kant hundreds of pages of incredibly dense philosophy; however, he laid out a theory of cognition capable of defeating Hume’s problem of induction. This very problem which potentially undermines the majority of modern scientific thought inspired Kant to “awaken” from his “dogmatic slumber,” and so it is only fitting that one of his most major philosophical works succeeds in resolving this problem.