3. The Conceptual/Perceptual Dichotomy

A concept is a reference to a part of subjective experience, or a generalization of percepts.

There is a conceptual universe which consists of references to perception.[64] When understanding the conceptual universe, it is a universe with no boundaries; when perceiving it, it is a small part of the subjective universe (we perceive things other than concepts). Concepts are abstractions (or generalizations) of percepts, which live in a space with a radically different dimensionality than that of the things that they reference.

The perceptual domain is composed of perception: it includes sensation, excludes conception, and consists of references to objective reality.

If we hear someone speaking and we do not conceptually understand them, the utterance remains at the level of perception: the percepts do not become concepts. If we do understand them, concepts are activated, which potentially give rise to further concepts. This distinction between thought-as-perceived and thought-as-conceived lies at the root of a difference in the categorization of the senses which is exemplified by several eastern and western cultures. In western culture, perception is most often divided into five external parts and perhaps one or two internal senses, but cognition is left out (it operates on perception). In eastern cultures, cognition is often included in the domain of perception: it is something which is perceived. This difference in the relative position of conception is illustrated visually in the next two pictures.

In the following diagram, conception is represented as something which operates on perception (as opposed to something on which perception operates):

In this diagram, individual (external) senses are collected together into perception. Perception occurs at a location in which the senses are united in a perceptual space (these percepts are subsequently united in thought, as concepts). All perception, both external and internal, is spatial. This is immediately apparent for senses like sight, since they are instrumental in the formation of our spatial awareness in the first place. For example, everything in space that we see has a color, which occurs where the object with that color is present. It is also true of the internal senses: for example, taste occurs in the mouth, when we lick something.

In the following diagram, perception occupies the terminal position: concepts themselves are perceived, just as all other phenomena.

The rationale for introducing these two mental models is to set up an east-meets-west diagrammatic fusion. In the resulting mental model, conception is both something that is itself sensed as well as something that operates on data from other senses. As such, thinking is both something that can be perceived (as perceptual data) and conceived (as conceptual data).[65] Pictorially, information flows to and from the mental sense as follows:

This diagram is markedly dissimilar from the previous two diagrams in that it contains a feedback loop. This loop is analyzed in detail in Chapter 9, Conceptual/Conceptual References .

The conceptual domain is composed of things called concepts, which are references to percepts.

Concepts are things that are able to categorize the perceptual domain; exactly how they categorize that domain is driven by the desires of the organism.

A concept is often defined in one of two ways: either as a prototype or a collection. If a concept is defined as a prototype, then it is in some sense the perfect example of the category it represents. In this case, things are apples to the degree that they are similar to a single prototypical “apple” concept. If a concept is defined as a collection, then it represents a (potentially large) number of prototypes. In this case, however, there is not necessarily a single prototype that best represents the concept. Prototypes and collections both serve to define concepts: these correspond to conceptual and perceptual definitions. While concepts may be formed by collecting other concepts, they are still ultimately reducible to functions operating on perception. In contrast to either of these two definitions, the perspective that we wish to emphasize is that a concept represents a dichotomy: we cannot create the concept “bird” without at the same time dividing the universe (or some restricted domain thereof) into bird and non-bird things.

Concepts are categories of percepts which are the result of partitioning something.

Given a domain of discourse, a concept is defined as a proposition which selects some part of that domain. This proposition creates a decision boundary which partitions the input space: in other words, given a particular domain, a concept (which may or may not be associated with a given name) is associated with one of two ranges formed by the partition of the domain.

Each concept acts on its given domain as a function which forms a binary partition: such functions are called propositional functions, or simply propositions. In general, propositions should be understood as a function that can result in truth, falsity, or some value in between. As a simple example of a proposition, consider isAnApple(x) , which yields a value indicating whether certain percepts indicate the presence of an apple. This proposition, since it identifies or recognizes a given object with a range of values in between true and false, might properly be called a fuzzy proposition (fuzzy logic is the extension of classical logic to multivalued truth functions).

Despite the utility of fuzzy properties, concepts are notoriously binary-valued. Although being binary valued is not a necessary feature of concepts, it is certainly quite common. People who are highly conceptual seem particularly prone to this sort of black-and-white thinking. This unnecessary polarity may be due to the fact that concepts, even if they are only somewhat true or false, exclude other concepts from being conceived at the same time. In other words, even if a concept is not binary valued, it may result in categorical thinking in virtue of the fact that it presupposes one point of view as opposed to another.

[64] For Aristotle, perceptions were united in what he called the “common sense” . The common sense unites the various subjective perceptions of the apple (i.e. the sight, smell, and taste). This book refers to these united things as concepts, and to the universe in which they live as the conceptual universe.

[65] This model is not a completely novel addition to either eastern or western thought: it is a combination of different emphases.