John Locke (1632 –1704) is better known now for his political thought than his Empiricism. Locke spent time in Holland as a young man and his political thought was probably influenced significantly by Spinoza who had died only recently. Locke argued against the divine right of kings to rule and instead defended a liberal egalitarian political philosophy on which people have equal and natural rights to liberty. Liberty, in Locke’s thought, should be understood as being free from domination by others. Liberty is not in Locke’s view being free to do whatever one pleases. For starters, if everyone is to be free from domination, then it follows that nobody is free to dominate. Locke also offers the classic justification for property rights as an extension of our self-ownership. So property rights are seen as natural extensions of our human liberty. The point of government is just to secure our natural liberties to the highest degree possible on Locke’s view. So government is legitimate only when it is limited to this role. This view should sound familiar. Locke’s political philosophy was influential with the founding fathers of the U.S. Thomas Jefferson in particular was a close student of Locke’s political thought. We will return to Locke at the end of the course when we take up political philosophy. But for now, we’ll say a little about his epistemology.
Locke develops his empiricist epistemology in his Essay Concerning Human Understanding. Locke’s approach is to examine the origins of the contents of the mind. Early in this work he argues against innate ideas. The mind starts off as a tablula rasa, a blank slate. All of our ideas have their origin in experience. Simple ideas, say of solidity and figure, are acquired through the senses, and from these we form complex ideas, say the idea of a dog, through the capacities of the understanding. The details of this account raise a number of challenging questions. We might think of Locke as launching a research program for developing an empiricist account of the mind rather than spelling out a fully developed view.
Locke thinks that some of the impressions we get from sense experience are genuinely similar to how things are objectively in the world. Our sense experience of the shape of things, for instance, reflects the ways things really are according to Locke. Locke refers to the qualities where there is a resemblance between our experience and the way things are as primary qualities. Shape, motion or rest, and number are a few of the primary qualities. Other aspects of our sense experience don’t resemble the qualities in their objects. The taste of an apple, for instance, is not really in the apple. What is in the apple is just a power to produce the experience of a certain flavor. But we have no grounds for thinking that this power as it exists in the apple resembles in any way the sense experience we have of its taste. Locke calls qualities where our sense experience doesn’t resemble the qualities that give rise to our experience secondary qualities. Our knowledge of the external world, then, is based entirely on our experience of the primary qualities. Empiricism, as we will see in the case of later empiricists, especially Hume, tends to place sharp limits on what is knowable.
While all experience depends on having simple ideas had through sense experience, Locke does not take experience to be limited to these. We also have experience of the operations of the mind in building up complex ideas out of simple ideas. Once you have some simple ideas through sense experience, you also have an experience of yourself and of your mental operations on those simple ideas. So given simple ideas through experience, the operations of the mind become a source for further ideas. Locke thinks knowledge of the self, God, mathematics, and ethics can be derived from this additional internal source of experience. Hume, as we shall see, is not so optimistic.