Reid's Critique of Berkeley and Hume: What's the Big Idea?

Abstract

Thomas Reid thought that the linchpin of his response to Berkeley and Hume was his rejection of the common theory of ideas. On this point his commentators have generally taken him at his word, so much so that it is difficult to find one who explicitly disagrees.' In this paper I will argue that Reid's assessment of his own work is incorrect. Specifically, I will argue that there are two main arguments for skepticism in Berkeley and Hume, although Reid never clearly distinguishes them and in fact tends to run them together.2 One of these arguments, which I will call 'the inconceivability argument for skepticism,' begins by establishing the impossibility of the conception of external objects and their qualities. But since belief requires conception and knowledge requires belief, it follows that we can have no knowledge of the external world. The second argument for skepticism, which I will call 'the evidential argument,' turns on the impossibility of our providing adequate evidence for our beliefs about the external world. My thesis will be that Reid is correct about the centrality of the theory of ideas in the first argument for skepticism, but he is incorrect about the centrality of the theory in the second. I will argue that the theory of ideas in fact plays no important role in Berkeley's and Hume's evidential argument for skepticism, and that rejecting it is therefore neither necessary nor sufficient as a reply. However, I will argue that Reid does in fact provide the materials for an adequate reply to the evidential argument. But the linchpin of that reply is Reid's theory of evidence, not his rejection of the theory of ideas.