Unlike Descartes, philosopher John Locke did not believe in innate ideas, those which you are essentially born with. Instead he fostered the idea that our mind was more like a blank slate. He called this the tabula rasa. Experiences gained through senses and reflection filled this slate.(1)
Locke borrowed an age-old distinction of simple and complex ideas from Descartes. He described simple ideas as those which originate in one sense and cannot be broken down any further. An example of a simple idea would be color. Complex ideas are a combination of simple ideas. It was with these two types of ideas that one could know the primary and secondary qualities of an object.
Locke maintained that all objects have certain attributes that fall into two categories which are primary qualities and secondary qualities. Primary qualities exist in the object. The shape, size and location of an object would all be considered some of its primary qualities. These qualities are objective according to Locke, because they are perceived the same to everyone. Secondary qualities are the attributes that the perceiver brings to the object such as smell, taste, color and sound. Obviously these types of qualities are subjective because not everyone has the same taste or sense of smell. John Locke believed that error to knowing something lied in the secondary qualities.
Locke built his theory of representative realism upon these ideas. He once said, “The mind represents the external world, but does not duplicate it.” This is an area that Descartes and Locke agreed on. They believed that instead of actually experiencing the world first hand we indirectly experience it through representations.(2) We used the example of a photograph in class stating that what appears in the photo is not fully accurate compared to reality. Some of what you perceive is correct and some is not. You may see red eye or a glare. Just because you see those things does not mean they actually exist in reality.
Locke’s theories seem to make the most sense to me. His ideas are held by many and are likely regarded as unmistakable to most people.(1) As popular and easy to understand as Locke’s theory may be that doesn’t make it a sound epistemological theory. Berkeley sought to crack holes in what could have been a solid theory.
Berkeley, being the most extreme of the empiricists, disagreed with Locke on the idea of primary and secondary qualities. He maintained that you couldn’t know an object through its primary qualities and that in fact they were just as subjective as the secondary qualities.(2) In response to Locke’s claims that size and shape were primary qualities he would object saying that they are subjective and rely on the perceiver. For example, you look at the sun and it appears to only be the size of a quarter in the sky because of the distance that you are away.
In my opinion Locke’s theories appeal more to common sense then rational thinking. I believe almost anyone who has not taken a course in philosophy would likely agree with Locke’s ideas. People would come to the conclusion that just because you are perceiving the sun as smaller from a distance, doesn’t mean that the sun itself has actually changed in size.
1) Bruder, Kenneth, and Brooke N. Moore. Philosophy - The Power of Ideas. 5th ed. N.p.: Kenneth King, 2002. 106-107.
2) LaFave, Sandra. Locke and Berkeley. 16 Aug. 2002. West Valley College. 3 May 2004
3) Materials from our class notes were also used.