Locke’s distinction between primary and secondary qualities forms a significant part of his theory of representative realism. This theory can be seen as a correction (rather than an analysis) of the general, unconsidered views of the average person which can be categorised as naïve realism. In his work, An essay concerning human understanding, Locke discusses the theory that the ideas we have, in our minds, of the external world are merely representative of what is really out there. He considers how much we can really know about the objects we perceive and this analysis leads him to distinguish two types of quality present in the external world which our perception recognises in different ways. He calls these primary and secondary qualities.

Primary qualities are those which are inseparable from the object of our perception in that the object would cease to be as it is if these qualities were not present in it. Our ideas of these qualities closely resemble the actual qualities themselves. An example of this, which

J.L. Mackie, Problems from Locke, Clarendon Press, 1976

Mackie suggests, however, that this theory could be problematic. This is because he does not believe it to be universally true. He cites the example of smell and taste, which are both secondary qualities but frequently work simultaneously. This seems like a weak objection though as it can easily be over come by re-categorising our concept of the senses and listing smell and taste as one and the same which would seem to make sense as they are so closely linked. For example, if we lose our sense of smell, we also lose our sense of taste.

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George Berkeley, , Aristotle Aristotle, Berkeley Locke, secondary qualities, primary qualities, primary secondary qualities, primary secondary, distinction primary secondary, locke’s theory, distinction primary, external world, Clarendon Press, Kegan Paul, Understanding Routledge, Philosophical Analysis2nd, Knowledge Collins, theory representative realism, theory representative, representative realism, list primary qualities, qualities â€, list primary, primary qualities â€, Human Understanding,