Chapter 15 explored the basic properties of ideas or concepts, and Chapter 16 defined what it is to possess them. This chapter looks at how we come to possess concepts. We will identify four sources: observation (abstraction), communication, constructive thought, and abstractive thought. Psychological investigation of concept formation has focused on a process called “concept learning.” Since the process involves the formation and testing of hypotheses containing the concept to be acquired, it cannot be a way of acquiring concepts. This fact has been used to argue that all concepts are innate. But the argument assumes groundlessly that concept learning is the only method by which concepts could possibly be acquired. The proper conclusion to draw is that since concepts are thought-parts rather than beliefs, the acquisition of concepts is not a belief-forming operation. We will explore the possibility that some concept-formation processes, involving observation and abstraction, are basic psychophysical processes. I believe that the concentration on concept-learning experiments can be traced back to the historical confusion between the acquisition of concepts and the learning of word meanings.

ACQUISITION

We are said to acquire or form a concept when we change from nonpossession to possession.

Definition: S acquired (formed) concept C at t iff S possessed C at t but not before.

Acquisition coincides with an initial occurrence marking the beginning of a period of possession, during which the concept may or may not reoccur.