Lewis, Clarence Irving (1883–1964)

The American philosopher C.I. Lewis held that in all knowledge there are two elements: that which is presented to sense and the construction or interpretation which represents the creative activity of the mind. Contrary to Kant, Lewis claimed that what is fixed and unalterable is not the structure that we bring to the sensibly presented, but rather the sensibly presented itself. The categories that mind imposes do not limit experience; they determine the interpretation we place upon experience, and if too much of experience eludes our categorizations, new ones should be established. It is pragmatically necessary that we create interpretive structures which will work in getting us around in sensory experience. This important and novel doctrine, Lewis’ ‘pragmatic a priori’, emerged through the development of ideas which took root during his study of logic. The problems of choosing among alternative logics led him to assert the need for pragmatic criteria. The way we conceptually structure or categorize experience answers to pragmatic criteria of purposes, intents and interests. Only within a context defined by a priori categorizations can empirical judgments be made. These empirical judgments proceed from apprehensions of the sensibly presented to assertions of objectivities. Moral judgments require both judgments of good and decisions of right. Judgments of value are tied to qualitative satisfactions disclosed in experience and are empirical claims. Decisions about the morally right are based on imperatives of reason.