Abstract+Ideas

When we generalize commonalities from particulars, we generate "Abstract Ideas". For instance, after we observe "that Monarch Butterfly" and "this Eastern Tiger Swallowtail Butterfly" we begin to generalize an idea: BUTTERFLY and begin referring to such winged, six-legged creatures as "butterflies". For, from these general ideas come general terms.

John Locke
(29 August 1632 – 28 October 1704) Locke was the most infamous expositor of abstract ideas, and used them to show errors in his ancient predecessors Plato and Aristotle and modern ones, like Descartes.

Locke erroneously asserts that to have an entire world of uniquely named //things// is an impossibility, as it is "beyond the power of human capacity to frame and retain distinct //ideas// of all the particular things we meet with," (//Essay Concerning Human Understanding//, III.iii.2) such as every particular bird or tree. Criticism on this point begins with what sort of impossibility Locke is claiming--limitations within our language, counting ability ("certain number of real essences"), empirical evidence, modes of recollection? A flaw in this argument further stems from his misuse of the term "particular," as he assumes a one-to-one //linguistic// correlation between an object or an idea and its object. For example, that there has to be a single term for every tree, when a more useful formula might read that a qualifier plus its corresponding universal signifies a particular, i.e. THAT mountain, the CONNECTICUT River, the RED ball. The latter term is the universal and Platonic form, while the former term qualifies and distinguishes to the point of providing no impossible lack of unique names. He later clarifies the limitations as being "bound by the species," or the "nominal essence," and that these are only useful commonly, and when ranking and categorizing. To illustrate this idea of nominal versus real essence, he uses the example of gold. "//The nominal essence of gold is that complex idea the word gold stand for- let it be, for instance, a body yellow, of a certain weight...But the real essence is the constitution of the insensible parts of that body, on which all those qualities...of gold depend. (Essay,// III.vi.2)

Problems with Plato
For instance, he writes against Plato, "general and universal //do not belong to the real existence of things."// (//Essay//, III.i.10) Rather than particular objects of experience gaining their identity from participating in the universal and perfect "Form" of that object, universal ideas are simply generated for practical purposes of communication.

"For the signification [the generals] have is nothing but a relation that, by the mind of man, is added to them." (//Essay//, III.i.11) According to Locke, Plato's Forms are just a creation of man, and they have no significance.

Problems with Aristotle
A similar "pragmatic" stance is taken by Locke toward Aristotle. Aristotle held that the true nature of objects can be discovered through a definitional process of "genus-species difference": as we inspect all individual objects, we begin to notice differences between them and other objects that are similar to them we can claim that these unique properties are necessarily part of a particular species. In other words, whatever qualities make a species distinct from other species in its genus are necessarily part of that species. For example, when the species, "human" is compared with all other animals in its genus, we observe that "human" is different because of its ability to reason. Hence, humans must be rational or "//Man is a Rational Animal//".

1) For Aristotle knowledge only comes from Primary Sources (Individual) 2) Genus-species difference is from Secondary Sources (Universal) 3) So, genus-species difference does not provide knowledge

However, as Locke notes, a better kind of definition is by enumeration, or naming each individual of each species. For instance, the best way to define number is by enumerating all the individual numbers (start counting!). But, since communication would be stunted by this process, we use general ideas and their linguistic representation, words.

**Problems with Descartes**
Like Aristotle (surprisingly unlike Plato, given that Descartes is for the most part a Platonist), Descartes argued that we can know the nature of an object by discerning its "genus difference". As he writes, "//...each substance has one principal property which constitutes its nature and essence, and to which all its other properties are referred. Thus extension...constitutes the nature of corporeal substance; and thought constitutes the nature of thinking substance." (Principles)// Locke, however, considers the notion of "essences" or "substance" to simply be unknowable by the human mind. Substance, for Locke, is the "I know not what". So, there can be knowable property which defines an objects identity.