George Berkeley (1685-1753) considered Locke’s theories concerning secondary qualities being ‘mind dependent’, and considered that his theory did not go far enough. Why shouldn’t this be true of primary qualities as well? Why shouldn’t the whole of the external world be ‘mind dependent’?
Our senses create ideas of sight, sound, taste, smell & touch.
One example Berkeley uses is of ‘ordure’ (human excrement). The smell of human excrement is unpleasing to man, and yet it appears quite agreeable to brute animals. Therefore, he claims, the smell cannot be a quality of the object otherwise we would all experience it in the same way. Consequently, Berkeley concludes that the smell must be ‘perceptually relative and perceiver dependent’. It is the idea of the smell which causes us displeasure
Berkeley’s argument for the perceiver-dependent nature of primary qualities
A tiny insect such as a ‘mite’ would consider its foot as being quite large, however, to a human being it is incredibly small, therefore, Berkeley considers that extension is not ‘inherent within the object’ otherwise its size would be viewed the same by all who perceived it. Dimension must be an idea within the perceiver’s mind.
According to Berkeley, objects of perception are nothing more than a collection of ideas, and this leads to the conclusion that existence depends on perception.
When things are not perceived, they cease to exist
The most obvious response considered how it was that plants continued to grow when nobody was observing them. Surely if Berkeley’s theories were true, a plant left unobserved for a week, would remain exactly the same size?
In the Twentieth Century, Bertrand Russell gave a similar example concerning a cat; where you observe a cat in motion, look away, look back and it has moved.
The belief that objects ceased to exist when not perceived though, was not really what Berkeley had in mind. Objects, he considered, do not depend upon us to perceive them, because they are always being perceived by God.
For Berkeley, the world existing as it does, is in fact proof for the existence of God. Although critics claim that Berkeley is using God to explain his theories, it is in fact the other way round, Berkeley is using his theory to prove God’s existence.
· It responds to the problem of subjectivity in the physical world; we all perceive things differently
· It emphasises the importance of God within the physical world. Philosophers have ignored God in the idea of perceiving the world. He believes that God is ‘seeing’ the objects, therefore causing them to ‘exist’
· It supports the possibility that the world is subject to doubt, but our senses are not. The world might not exist, we can only rely on what we perceive through our senses, we are merely creating ideas.
· It is a very difficult theory to prove wrong
Solipsism is the view that nothing exists except one’s own self and the contents of one’s consciousness. (The Cogito) Ultimately it means that a solipsist only believes in his own existence, and of nothing else. This is compatible with Idealism, because a solipsist would consider that everything observed in the physical does not have existence in its own right, it merely exists as ideas within his own mind.
Although it is impossible to refute a solipsist’s claim, it does not seem logical to assume that I inhabit a world where everything is no more than the product of my own mind. In fact Russell claimed that solipsism was more of a philosophical disease than a philosophical theory.