Kant – Transcendental Idealism

Phenomena and noumena: Kant distinguishes between the inner, mind-dependent realm, and the outer, objective mind-independent realm.

1. Phenomena: Kant begins by noting that all that we perceive are nothing but representations or appearances. He calls this realm of perception the realm of intuition, or sensibility. The OBJECTS of perception (or intuition, or sense) are called “phenomena.” (These are similar to what Locke and Berkeley mean by “ideas”) Like Berkeley, Kant says that phenomena are dependent on the mind. If we ceased to exist, the phenomena would ALSO cease to exist. He writes, “they cannot exist in themselves, but only in us.”

2. Noumena: In contrast to phenomena are the “noumena.” These are the “things-in-themselves,” or (elsewhere) the “transcendental objects.” They are the objects of the external world. But, they are not sensible things (i.e., they cannot be perceived). He writes, “we do not apprehend them in any fashion whatsoever.” Of them, we know “nothing whatsoever.” If we COULD know the noumena, we would know things “as they ARE”—whereas, to know the phenomena is merely to know things “as they APPEAR.”

This appears to be a radical form of skepticism, where the existence of the external world is a complete unknown.

On skepticism: Skeptics claim that all we perceive are appearances. But, from the concept of an appearance, it naturally follows that there exists something that the appearance is OF, and which is not ITSELF an appearance. Kant writes, “the word appearance must be recognized as already indicating a relation to something … that is, an object independent of sensibility.” (This seems to be the way in which Locke dealt with skepticism.)

However, if we take this route, all that we can conclude is THAT something external exists. We cannot know WHAT this something is. In other words, we would know something NEGATIVE about external objects—namely, that they are NOT appearances. We would not, however, know anything POSITIVE about them. Even worse, it might be the case (as Berkeley noted) that the “external” source of those objects is not anything material at all. Rather, the cause could be a mind (e.g., God, as Berkeley thought)—even our OWN mind. Kant writes,

For if we regard outer appearances [i.e., phenomena, or ideas, of external objects] as representations produced in us by their objects, and if these objects be things existing in themselves outside us, it is indeed impossible to see how we can come to know the existence of the objects

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otherwise than by inference from the effect to the cause; and this being so, it must always remain doubtful whether the cause in question be in us or outside us.

Transcendental Idealism: Kant argues that we do not need to perform this sort of Lockean inference to the external world, which only results in a “doubtful” conclusion. Rather, we CAN make claims about external things like tables, chairs, hands, etc. with absolute certainty. (…Sort of)

In any case, this is the goal of his “transcendental idealism.”

Kant begins by distinguishing between what he calls “idealism”—the view that the existence of external objects is doubtful—and what he calls “realism”—the view that the existence of external objects is certain.

The idealist knows that the internal world of appearances is certain (e.g., in the same way that Descartes knows with certainty that his thoughts exist). However, the idealist can only, at best, INFER the existence of external objects as the cause of those appearances that occur to us in our intuition—and, this sort of inference is not certain.

Empirical realism: Nevertheless, Kant does embrace a form of realism, which he calls “EMPIRICAL realism.” This seems to be the view that, although we can only ever know the phenomena and not the noumena (i.e., we can only ever perceive internal appearances, and not the external “things-in-themselves”), we CAN accept a form of realism, so long as realism is described as the view that “the existence of external objects is certain.”

Kant states that, even though we never perceive the noumena, we CAN be certain that what we perceive is “real” and “external.”

These terms are mis-leading, however:

• The “real” world: By “real,” Kant only means to say that the representations, or appearances, EXIST. This existence is only within our perception, however. So, “The reality of outer appearances is therefore real in perception only, and can be real in no other way.”

• The “external” world: By “external,” Kant only means to say that the objects of appearances are REPRESENTED as being IN SPACE, and OUTSIDE of us. To avoid confusion, he later calls this sort of external, “empirically external” (as opposed to REALLY external, or OUT THERE, outside of the mind, as most of us think of the term).

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Kant concludes,

Thus external things exist as well as I myself, and both indeed, upon the immediate witness of my self-consciousness. The only difference is that the representation of myself, as the thinking subject, belongs to inner sense only, while the representations which mark extended beings belong also to outer sense. . . . [But] in both cases alike the objects are nothing but representations, the immediate perception (consciousness) of which is at the same time a sufficient proof of their reality. The transcendental idealist is, therefore, an empirical realist, and allows to matter, as appearance, a reality which does not permit of being inferred, but is immediately perceived.

So, unlike the traditional idealist (e.g., Locke, Berkeley), the existence of external objects does not need to be INFERRED. Rather, external objects are immediately PERCEIVED, and are known with certainty to exist externally.

Though, keep in mind that Kant is only referring to phenomena, which are only “real” and “external” in Kant’s peculiar sense, and (strictly speaking) he does not think that we can know anything about THE external objects (i.e., the noumena).

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