G. E. Moore - Proof of An External World

Proof of An External World

One of the most important parts of Moore's philosophical development was his break from the idealism that dominated British philosophy (as represented in the works of his former teachers F. H. Bradley and John McTaggart), and his defence of what he regarded as a "common sense" form of realism. In his 1925 essay "A Defence of Common Sense", he argued against idealism and scepticism toward the external world on the grounds that they could not give reasons to accept their metaphysical premises that were more plausible than the reasons we have to accept the common sense claims about our knowledge of the world that sceptics and idealists must deny. He famously put the point into dramatic relief with his 1939 essay "Proof of an External World", in which he gave a common sense argument against scepticism by raising his right hand and saying "Here is one hand," and then raising his left and saying "And here is another," then concluding that there are at least two external objects in the world, and therefore that he knows (by this argument) that an external world exists. Not surprisingly, not everyone inclined to sceptical doubts found Moore's method of argument entirely convincing; Moore, however, defends his argument on the grounds that sceptical arguments seem invariably to require an appeal to "philosophical intuitions" that we have considerably less reason to accept than we have for the common sense claims that they supposedly refute. (In addition to fueling Moore's own work, the "Here is one hand" argument also deeply influenced Wittgenstein, who spent his last years working out a new approach to Moore's argument in the remarks that were published posthumously as On Certainty.)