In the Essay Locke argues abstract ideas within the framework of the descriptivist theory of reference. For him, abstract ideas are, in many cases, conceptual ideas that play the role of “descriptions” or “descriptive contents,” determining general terms’ referents. In contrast, in the introduction of the Principles, Berkeley denies Lockean abstract ideas adamantly from an imagistic point of view, and he offers his own theory of reference seemingly consisting of referring expressions and their referents alone. However, interestingly, he mentions a (...) general term’s “definition” and suggests that it determines the scope of the term’s referents. For example, he takes up the definition of a triangle as “a plain Surface comprehended by three right Lines” and suggests that just as Locke’s general idea of a triangle does, the definition determines the referents of the general term “triangle.” His definition reminds us of the fact that as Descartes grasps the content of the general idea of a triangle as “a figure enclosed by three lines,” so Locke grasps the abstract idea of a triangle as “a Figure including a Space between three Lines,” and so on. That is, since Berkeley is an imagist, he does not acknowledge Locke’s conceptual abstract ideas as “ideas,” but although he verbally denies “abstract ideas,” his theory of reference also actually has the same descriptivist framework consisting of referring expressions, their descriptive contents, and their referents. Thus, we understand the real reason why Berkeley’s criticism of Locke seems beside the point. (shrink)

Molyneux’s question asks whether someone born blind, who could distinguish cubes from spheres using his tactile sensation, could recognize those objects if he received his sight. Locke says no: the newly sighted person would fail to point to the cube and call it a cube. Locke never provided a complete explanation for his negative response, and there are concerns of inconsistency with other important aspects of his theory of ideas. These charges of inconsistency rest upon an unrecognized and unfounded assumption (...) that seeing entails recognition. Locke’s negative answer to Molyneux’s question is consistent with his other philosophical commitments. (shrink)

A great deal of the criticism directed at Locke's theory of abstract ideas assumes that a Lockean abstract idea is a special kind of idea which by its very nature either represents many diverse particulars or represents separately things that cannot exist in separation. This interpretation of Locke has been challenged by scholars such as Kenneth Winkler and Michael Ayers who regard it as uncharitable in light of the obvious problems faced by this theory of abstraction. Winkler and Ayers argue (...) that Locke instead held that to have an abstract idea is to attend selectively to some portion of the content of a particular idea. On this view, to have an abstract idea is not to have a special kind of idea but to have an ordinary idea in a special way. Ayers argues that Locke inherited this theory from Arnauld. I argue that the case made by Ayers for the attribution of the extrinsic theory to Locke rests on a misinterpretation of Arnauld. In fact, both Locke and Arnauld regard selective attention as part of a process whereby a new kind of idea is constructed. (shrink)