Good Article On Locke's Ontology: Primary and Secondary Qualities of Perception:
[CENTER]Empiricism and the Substratum of Reality
[INDENT] In John Locke's "Essay Concerning Human Understanding", he makes a distinction between the sorts of ideas we can conceive of in the perception of objects. Locke separates these perceptions into primary and secondary qualities. Regardless of any criticism of such a distinction, it is a necessary one in that, without it, perception would be a haphazard affair. To illustrate this, an examination of Locke's definition of primary and secondary qualities is necessary.
Starting from common-sense notions of perception, namely that there must be
something in order to perceive
something, Locke continues by arguing that ideas in the mind correspond to qualities in the object being perceived. Locke states that:
[INDENT]Whatsoever the mind perceives in itself, or is in the immediate object of perception, thought or understanding, that I call idea; and the power to produce any idea in our mind, I call quality of the subject wherein that power is. 11
[/INDENT] Primary qualities are those aspects of an object that are in and of the object being perceived. Anything that must actually be in an object in order for any object to exist is a primary quality. These, Locke stated, are inseparable from an object. Qualities such as mass, solidity, and extension in three dimensions are all primary qualities. To say that an object has mass and solidity but no shape or extension in three dimensions is inconceivable if not outright ridiculous. So, primary qualities are necessary for an object to be considered an object. If something does not have primary qualities, then it cannot be considered an object but must be considered to be something else.
Secondary qualities, according to Locke, are our interpretation of the effects that primary qualities have on our perceptions and the ideas that come from these perceptions.
[INDENT]such qualities which in truth are nothing in the objects themselves but powers to produce various sensations in us by their primary qualities, i.e. by the bulk, figure, texture and motion of their insensible parts, as colours, sounds, tastes, &c... 22
[/INDENT] Our senses are limited to a certain stratum of perception. We cannot, with our naked eyes, see the workings of atoms, nor the interplay of light particles and atoms in objects in the production of colour. However, we can see the results of those interactions, and when light reflects off an object, we can absorb that light with our eyes. Now, when that sense stimulus produces an idea in our minds we interpret it as a colour such as red, green, blue, and so on. This is what Locke meant by secondary qualities.
With this distinction in mind, primary qualities are necessary for an object to be an object while secondary qualities are not. Secondary qualities are contingent upon a perceiver to interpret the sensations produced by primary qualities. Primary qualities are the cause; secondary qualities are the effect.
Nowhere in this essay has the notion of substance or matter been mentioned but it has been assumed. The assumption of the notion of substance in the foregoing distinction of primary and secondary qualities of objects is where George Berkeley's Idealism finds fault with Locke's materialistic account. What Locke assumes substance to be is what cannot be sensed but what must necessarily be, for primary qualities of an object need a substance in which these primary qualities adhere and exist independent of a perceiver. However, the objections to the notion of matter through the criticisms of the distinction between primary and secondary qualities are ill-founded.
In section 41 of Berkeley's "Principles of Human Knowledge" he states that:
[INDENT]If real fire be very different from the idea of fire, so also is the real pain that it occasions very different from the idea of the same pain, and yet nobody will pretend that real pain either is, or can possibly be, in an unperceiving thing, or without the mind any more than its idea. 33
[/INDENT] This passage plays on Locke's distinction between primary and secondary qualities in that the object (fire) through its primary qualities causes the secondary quality (pain) in the perceiver. Berkeley thought that primary qualities causing secondary qualities would be equally true within a world without matter or substance.
However, if there is naught but ideas, and the idea of fire burns a hand by the perception of pain on the part of the perceiver, then where is the separation of the idea of fire within perception and the idea of fire within contemplation? Both happen within the mind of the perceiver yet one produces the real sense of pain while the other does not. In other words, if my perceptions are of ideas and of ideas only, then where is the division in the mind between thought and perception?
There is a very real distinction between thought and perception, a distinction between the perception of being burned by fire and my conception of being burned by fire. So there must be a wedge between thought and perception that drives them apart. Berkeley's Idealism cannot provide such a wedge, as primary qualities have no substance in which they adhere, but in Locke it is substance that can separate perception from thought. There is a two step process at work in which substance is the cause of primary qualities, which cause secondary qualities in the perceiver, and then it is secondary qualities, which provide the basis of thought.
Berkeley objects to Locke's distinction in a second way whereby he attacks it through its definition. He states:
[INDENT]It is thought strangely absurd that upon closing my eyelids all the visible objects around me should be reduced to nothing; and yet is not this what philosophers commonly acknowledge, when they agree on all hands that light and colors, which alone are the proper and immediate objects of sight, are mere sensations that exist no longer than they are perceived? 44
[/INDENT] Here, Berkeley is still using Locke's distinction between primary and secondary qualities but advocating that secondary qualities are the only existing things about an object. However, while secondary qualities were admitted by Locke to be dependent upon a perceiver, primary qualities were never considered as such. Berkeley goes on to attack primary qualities through the assertion, by those, such as Locke, who postulate substance, "that [matter] cannot subsist without the divine conservation, which by them is expounded to be a continual creation." 55
And so, this assertion is to support Berkeley's position that primary qualities are therefore subject to being dependent upon a perceiver. If matter needs to be continually created by divine conservation and matter is the substratum that holds primary qualities together in an object, then objects and their primary qualities can cease to exist and be created anew depending on whether there is a perceiver or not. This "continual creation" is done through the will of God.
In this attack, Locke can have no defense for he freely admits to the existence of God. However, Berkeley's attack on Locke does not do much for getting idealism off the ground. The same "continual creation" of perceptions, which is dependent on God, is as needed in Berkeley's position as it is in Locke's. However, God's existence must be accepted as a matter of faith, and in faith a multitude of postulations can be proposed.
If, in his faith, Berkeley accepts the world and everything in it and the common-sense notion of reality as being correct but considers it as the perception of ideas created by God, then so be it. You cannot prove faith wrong, but neither can you prove it right. Locke's faith in God provided him with a conception of a material world where God creates substance and everything associated with it. Conversely, without a belief in God, Berkeley's position cannot be put forth, as there would be nothing to create the perceptions, and Locke's position becomes more likely. And if your faith leads you to the conclusion that there is no God, then you must put your faith in a material world for there is no other consistent world of which you could conceive.
1 Locke, Berkeley, and Hume. The Empiricists.
(New York: DoubleDay, 1974) p.24 [Back
2 Locke, Berkeley, and Hume. The Empiricists.
(New York: DoubleDay, 1974) p.25 [Back
3 Locke, Berkeley, and Hume. The Empiricists.
(New York: DoubleDay, 1974) p.166 [Back
4 Locke, Berkeley, and Hume. The Empiricists.
(New York: DoubleDay, 1974) p.168 [Back
5 Locke, Berkeley, and Hume. The Empiricists.
(New York: DoubleDay, 1974) p.168 [Back