Locke states that the mind at birth is like a blank slate, or tabula rasa, waiting to be written on by the world of experience. All human knowledge is derived from ideas presented to the mind by the world of experience. However, these ideas can be classified into two general sorts. There are complex ideas and simple ideas. Simple ideas are the immediate products of sensory stimulation, examples would be ‘yellow’, ‘bitter’, ‘warm’, ‘round’, ‘hard’ and so on. Complex ideas are constructions out of simple ideas, and are the product of internal mental operations.
