One of the most frequently discussed passages from Locke's An Essay Concerning the Human Understanding is that which occurs in IV.vii.9, where he writes:… the Ideas first in the Mind, ‘tis evident, are those of particular Things, from whence, by slow degrees, the Understanding proceeds to some few general ones; which being taken from the ordinary and familiar Objects of Sense, are settled in the Mind, with general Names to them. Thus particular Ideas are first received and distinguished, and so (...) Knowledge got about them: and next to them, the less general, or specifick, which are next to particular. For abstract Ideas are not so obvious or easie to Children, or the yet unexercised Mind, as particular ones. If they seem so to grown Men, ’tis only because by constant and familiar use they are made so. For when we nicely reflect upon them, we shall find, that general Ideas are Fictions and Contrivances of the Mind, that carry difficulty with them, and do not so easily offer themselves, as we are apt to imagine. For example, Does it not require some pains and skill to form the general Idea of a Triangle, for it must be neither Oblique, nor Rectangle, neither Equilateral, Equicrural, nor Scalenon; but all and none of these at once. In effect, it is something imperfect, that cannot exist; an Idea wherein some parts of several different and inconsistent Ideas are put together.I shall not pretend that what Locke is claiming in this passage is wholly clear, nor shall I try to defend the views expressed in it. My intention is to show that what he says here has been widely misinterpreted. It has become common to treat the contents of the passage as aberrant; as presenting a ridiculous variant on his main thesis on abstraction, or that very thesis elaborated with a foolish rhetorical flourish. But what is said in this passage is not something said elsewhere, nor is it an alternative to something said elsewhere. Here, and nowhere else, Locke shows awareness of implications for his doctrine of abstraction, of views he holds about simple ideas. (shrink)

This book investigates Aristotle’s views on abstraction and explores how he uses it. In this work, the author follows Aristotle in focusing on the scientific detail first and then approaches the metaphysical claims, and so creates a reconstructed theory that explains many puzzles of Aristotle’s thought. Understanding the details of his theory of relations and abstraction further illuminates his theory of universals. Some of the features of Aristotle’s theory of abstraction developed in this book include: abstraction is a relation; perception (...) and knowledge are types of abstraction; the objects generated by abstractions are relata which can serve as subjects in their own right, whereupon they can appear as items in other categories. The author goes on to look at how Aristotle distinguishes the concrete from the abstract paronym, how induction is a type of abstraction which typically moves from the perceived individuals to universals and how Aristotle’s metaphysical vocabulary is "relational.’ Beyond those features, this work also looks at how of universals, accidents, forms, causes and potentialities have being only as abstract aspects of individual substances. An individual substance is identical to its essence; the essence has universal features but is the singularity making the individual substance what it is. These theories are expounded within this book. One main attraction in working out the details of Aristotle’s views on abstraction lies in understanding his metaphysics of universals as abstract objects. This work reclaims past ground as the main philosophical tradition of abstraction has been ignored in recent times. It gives a modern version of the medieval doctrine of the threefold distinction of essence, made famous by the Islamic philosopher, Avicenna. (shrink)

Les Principes de la connaissance humaine sont l'occasion pour Berkeley de nier l'existence des idées générales abstraites. Il admet cependant l'existence d'idées générales, plus exactement d'idées déterminées à signification générale. C'est ainsi qu'il peut rendre compte de la généralité de certaines démonstrations. L'exemple choisi est celui de l'idée de triangle dans le cadre d'une démonstration géométrique. Mais peut-on également rendre compte de cette manière des démonstrations et des idées algébriques et notamment celle de quantité? In the Principles of human knowledge, (...) Berkeley clearly denies the existence of abstract general ideas. He assumes, however, the existence of general ideas or, more exactly, of determinate ideas with a general meaning. In this way, he explains the generality of certain demonstrations. He chooses the example of the idea of a triangle within a geometrical demonstration. But can he likewise account for algebraic demonstrations and ideas, and in particular for the idea of quantity? (shrink)

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)