6. Can we trust our senses?


In this chapter, we consider the work of the “British empiricists” of the early modern period. In particular, we consider John Locke, George Berkeley, and David Hume.


6.1 We contrast a priori and a posteriori reasoning, and we distinguish rationalism and empiricism.

6.2 We present the argument from perspectival variation, which is used to support indirect realism: the claim that (though material objects exist) we can’t perceive them directly: we can perceive them only indirectly, via our “ideas” of them.

6.3 We explain that animals perceive colors in very different ways, and we introduce the Locke’s distinction between primary qualities and secondary qualities.

6.4 We introduce Hume’s question: “By what argument can it be proved that the perceptions of the mind must be caused by external objects that are perfectly distinct from them and yet similar to them?”

6.5 We introduce and motivate Berkeley’s idealism (1685 – 1753): his shocking claim that material objects don’t exist.

6.6 We briefly consider direct realism: the claim that material objects exist and can be perceived “directly”.

6.7 We briefly summarize the relations between direct realism, indirect realism, and idealism.