John Locke (1632-1704)
Locke was an English philosopher, and one of the foremost thinkers of the Enlightenment. In fact, he is often referred to as the “Father of the Enlightenment”, because he was so influential.
Contrary to Descartes’ view, Locke posits that the mind is a tabula rasa, or blank slate, at birth. There are no innate, or God-given, ideas in the mind, only the capacity to have them (an innate capacity to reason). All of our knowledge must come from experience of the physical world, through sensory perception.
Locke’s chief argument against innate ideas, is that if such ideas existed, they would be universal in all men. However, he argues, there is not one single idea that is universally held. Previously, rationalists had argued that some ideas, such as morality and the idea of God and his goodness, were innate and universal, but Locke raises the point that there are many examples of people who have no conception of these ideas, such as children and the mentally ill. (Who he refers to as idiots. Yes, really.)
He also introduced the idea of simple and complex ideas, to distinguish between ideas that we gain through sensory perception, and ideas that we create in our minds. Simple ideas are the impressions we gain from sensory perception, i.e. the taste of something, or it’s colour or texture. They are the building blocks that allow us to create complex ideas in our minds. Complex ideas are the result of combining our raw sense impressions, for example, combining the ideas of roundness, fuzzy texture and the colour yellow to get the idea of a tennis ball.