A Defence of Common Sense

A Defence of Common Sense is an influential essay by the philosopher G. E. Moore. The essay attempts to refute skepticism by arguing that at least some of our beliefs about the world are absolutely certain. Moore argues that these beliefs are common sense.

In his first verse, he argues that he has certain knowledge of a number of truisms, such as "My body has existed continuously on or near the earth, at various distances from or in contact with other existing things, including other living human beings", "I am a human being", and "My body existed yesterday".

In his second verse, he argues that there is a distinction between mental facts and physical facts. He says there is no good reason to hold, as many philosophers of his time did, that every physical fact is logically dependent on mental facts, or that every physical fact is causally dependent on mental facts. An example of a physical fact is "The mantlepiece is at present nearer to this body than that bookcase is." Mental facts include "I am conscious now" and "I am seeing something now."

In his third verse, he argues against the existence of God and against the existence of the afterlife. He offers no explanation for this conclusion other than his own personal belief.

The fifth verse is an examination of the problem of other minds. Moore argues that "there are other 'selves'", but explains why this question has baffled philosophers. In other words, the sense data that he perceives through his senses are facts about the interaction of the external world and himself, but he (and other philosophers) do not know how to analyze these interactions.