Prejudices and errors of sense do from all parts discover themselves to our view; and endeavouring to correct these by reason we are insensibly drawn into uncouth paradoxes, difficulties, and inconsistencies, which multiply and grow upon us as we advance in speculation; till at length, having wander'd through many intricate mazes, we find our selves just where we were, or, which is worse, sit down in a forlorn scepticism.1 - George Berkeley
Of the three most prominent British empiricists, George Berkeley (1685-1753) and his contribution to the doctrine of empiricism is often overshadowed in the history of philosophy by the work of fellow empiricists John Locke and David Hume. One aspect where Berkeley distinguished himself was in his critique of Locke's work, especially his notions of substance and ideas. Prominent within Berkeley's work was his argument against the "tenet of extended, movable substances without the mind [and why it] depends on that strange doctrine of abstract ideas."2 In the course of this paper, I will explicate why Berkeley finds this doctrine strange, and why, on such an account, the existence of mind independent objects depends on this very doctrine.
To understand the novelty and importance of Berkeley's treatment of Locke's empiricism, it is helpful to understand the challenges faced by such an account. On Berkeley's view, much of the difficulty faced by philosophers in the acquisition of knowledge is entirely of their own doing --"that they have first raised a dust, and then complain, we cannot see" (TCPHU: 26). This has been especially so with those philosophers who hold the belief that the mind has the ability of conceiving of abstract ideas.3
On such an account, human beings not only have the ability to perceive external physical objects, but they are able to abstract many of the various constituent parts (qualities) of the object (e.g., extension, colour, movement, etc.). The mind, through a process of abstraction, can make sense of these qualities as exclusive to each other. It has the ability to capture these universal qualities in an abstracted form that can apply to all other perceived objects (or beings) with similar characteristics.4
In Three Dialogues between Hylas and Philonous (in which he constructs a fictional dialogue between himself and Locke), Berkeley argues against the possibility of abstraction:
PHILONOUS: Try if you can frame the idea of any figure, abstracted from all particularities of size, or even from other sensible qualities.
HYLAS: Let me think a little - I do not find that I can. PHILONOUS: And can you think it possible, that should really exist in Nature, which implies a repugnancy in its conception?5
Berkeley uses the term "repugnancy" to refer to what he views as Locke's (or Hylas') contradictory employment of sensible qualities in his conception of perception“of which the most problematic notion for Berkeley was Locke's inability to conceive of an object stripped of all its qualities and his notion of substratum as a mind-independent entity that does the work of unifying primary and secondary qualities (i.e., it is the stuff onto which these qualities inhere).6
However, on Berkeley's account, there is no need of the notion of substratum to unify primary and secondary qualities Ç what we perceive is the totality of what there is to be seen. "I am of a vulgar cast, simple enough to believe my senses, and leave things as I find them" (TDBHP: 63). Although Berkeley concedes that he is able to conceive of select objects as compounded that do not appear to us in ordinary experience (for instance, a centaur with a man's head and torso and a horse's legs), yet he cannot successfully isolate an idea of these objects (e.g., this centaur's hoof) as distinct from a particular colour or form.7 Berkeley concludes that if there is indeed such a successful process of abstraction, then it must only be available to the learned, since the common folk“"the generality of men which are simple and illiterate"“have absolutely no pretension to such a view. However, unlike Locke who was willing to take the absence of innate ideas in the feeble-minded and young as demonstrable proof of their non-existence, Berkeley goes further to attempt to see if the doctrine of abstraction is indeed salvageable. If we cannot have access to the notion of abstract ideas in experience, we will want to reject this notion as spurious.
In a comparison between man and beast, we find that beasts do not find themselves "making use of general signs for universal ideas; from which we have reason to imagine that they have not the faculty of abstracting or making general ideas, since they have no use of words or any other general signs" (TCPHU: 30). For Berkeley, the very existence of language among human beings becomes the necessary precondition for our use of particular terms (i.e., linguistic devices to represent abstract or generalized ideas).8 Moreover, if we understand how ideas become general, we may better understand how words become general in a particular discourse. However, it is important to note that it is not that Berkeley denies the possibility of general ideas, but abstract general ideas. It is possible to conceive of general concepts or ideas associated with objects such as extension, solidity, colour, etc., however, it is not possible to conceive of an abstract general idea such as an extended object without colour or a colourful object that is not extended. Berkeley suggests that if we "”annex a meaning to our words, and speak only of what we can conceive, I believe we shall acknowledge, that an idea, which considered in it self is particular, becomes general, by being made to represent or stand for all other particular ideas of the same sort" (TCPHU: 32). Thus, the meaning of the words can only be derived from what we have direct experience of.
However, we mistakenly, upon philosophical introspection, take our ideas of particular objects and "raise them to those sublime speculations that are conversant about abstract ideas" (TCPHU: 33). So just what is the source of this prevailing notion of the existence of abstract general ideas? On Berkeley's view, it would seem that it must be certain linguistic conventions and our tendency to err in turning particulars (which we have experience of) into universals. For instance, Berkeley argues that even our analytical definition of a triangle is not as absolute as one would think; absent from our definition of a triangle are features such as surface, colour, length of sides, and how the angles are inclined to one another. While one could argue that such subsequent features are not essential for our understanding of a triangle beyond its being a three-sided figure whose internal angles add up to 180 degrees, Berkeley takes this fact to mean that "there is no one settled idea which limits the signification of the word triangle" (TCPHU: 36). On this view, there exists no idea of an abstract triangle to which all triangles somehow conform.
Berkeley believes that he has demonstrated the impossibility of abstract ideas. By isolating their origins in our linguistic conventions and the incoherency of the necessary relationship they purport to maintain between substance and their related qualities, Berkeley believes he has shown that the concept of abstract ideas is untenable. Thus, we must endeavour in the course of our understanding to take ideas "bare and naked"“free from those "names which long and constant use hath so strictly united with them" (TCPHU: 38-39). On Berkeley's view, by understanding the source and tendency to misuse abstract ideas, we can safely extricate ourselves from the dust cloud raised by such philosophical introspection.
Berkeley sought to challenge the prevailing opinion among philosophers that "all sensible objects have an existence natural or real, distinct from their being perceived by the understanding" (TCPHU: 42). And it is the maintenance of this relationship between the existence of sensible objects and their actual perception that relies on the doctrine on abstract ideas to get off the ground. According to Berkeley, "their esse is percipi, nor is it possible they should have any existence, out of the minds or thinking things which perceive them" (TCPHU: 42). While he admits that he can abstract, for instance, the smell of a rose without thinking of the rose itself, Berkeley wants to maintain that it is impossible to conceive "any sensible thing or object distinct from the sensation or perception of it" (TCPHU: 43). On this view:
... all those bodies which compose the mighty frame of the world, have not any subsistence without the mind, that their being is to be perceived or known; that consequently so long as they are not actually perceived by me, or do not exist in my mind or that of any other created spirit, they must either have no existence at all, or else subsist in the mind of some eternal spirit. (TCPHU: 43)
If one believes that what Berkeley has said obtains, there can be no "other substance than spirit, or that which perceives" (TCPHU: 43). When contrasted against Locke's notion of perception, it is easy to see why Berkeley wants to reject his view. Locke maintains that primary qualities are mind-independent, while secondary qualities are mind-dependent. However, according to Berkeley, such a distinction is incoherent. Not only is such a distinction theoretically dubious, but also practically speaking he cannot "by any abstraction of thought conceive the extension and motion of a body, without all other sensible qualities" (TCPHU: 45). And this is really the crux of why Berkeley believes that the doctrine of abstract ideas is so strange. Berkeley has constructed his ontology to hold that an existent idea is an unperceiving thing is a manifest contradiction, for our very idea of the existence of qualities such as colour or movement is our perception of them. Thus, "in short, extension, figure, and motion, abstracted from all other qualities, are inconceivable" (TCPHU: 45).
1 George Berkeley, A Treatise Concerning the Principles of Human Knowledge (excerpts) in A.A. Luce and T.E. Jessop, The Works of George Berkeley Bishop of Cloyne (Thomas Nelson and Sons Ltd, 1949), p. 25. (Hereafter referred to as TCPHU).
2 TCPHU, pp. 45-46.
3 On this view, Berkeley argues against the "possibility of our having or forming as our total object either a) a sensory quality that cannot be realized alone in perception, e.g. space without colour and vice versa, or motion without a body moving, b) a purely general sensory quality, e.g. abstract extension, colour, triangularity, animality." TCPHU p. 27nf. Objects are known to us only through our sensory apparatus.
4 Berkeley goes on (using the example of the term man and animal) to elucidate how the mind uses self-abstracted ideas of qualities to acquire further abstract ideas of compounded beings; TCPHU, pp. 27-29.
5 George Berkeley, Three Dialogues between Hylas and Philonous, edited by Robert M. Adams (Indianapolis: Hackett Publishing, 1979), p. 29. (Hereafter labelled as TDBHP).
6 Actually, it was Berkeley's view that Locke's admission that we cannot actually have direct access to substratum in any positive way (only relative to its supportive unity of qualities of a substance -- while it is something, it is something "we know not what" -- -made his double existence model of the mind vulnerable to scepticism about the existence of external objects.
7 TCPHU, p. 29. Berkeley goes on to say further down the page, "...it is equally impossible for me to form the abstract idea of motion distinct from the body moving, and which is neither swift nor slow, curvilinear nor rectilinear; and the like may be said of all other abstract general ideas whatsoever." On this view, it does not appear possible to obtain an abstract general idea from these distinct particulars.
8 As we will see in the second section of this paper, the source of the notion of abstract ideas and language will be important.