John Locke And Substance In his essay, “A Supposition of He Knows Not What,” John Locke offers the reader an intriguing view of substances and ideas. He argues for the existence of substances in our world because there must logically be something greater than the ideas and thoughts that occupy our minds. His argument for their existence maintains that we cannot see substances in our realms, but we can perceive them and note their effects on other things around us. Locke first states that there are too many ideas in the world to stand alone. We cannot see these ideas that form in our minds, but we know that the ideas we have cannot persists as one single idea, because everything we think is “a complication of many ideas together” (Reality 90). Since the simple ideas we have cannot exist alone, there must be something larger behind them, and those, Locke asserts, are substances.
Locke maintains that we only see substances in our world as ideas, for they are too complex for us to perceive. Because of the qualities of our ideas, we are able to perceive that they exist. The only evidence we have for this belief is that we can put together ideas on our own, and we can also put together ideas about substances, therefore these substances must create our ideas. We perceive substances as ideas, because they are too complicated for our minds and far from our realm of existence. Therefore, Lockes notion of substances reverts back to Platos idea of a form: substances are things that underlie all thought, that we cannot perceive on our own, but must exist in another place for they form our foundations of thought and ideas.