Essay: A Defence of Common Sense

Overview
George Edward Moore defends the ordinary beliefs people take for granted, arguing that propositions like "other minds exist" or "there is an external world" are known with high certainty. He treats these common-sense propositions as the baseline of knowledge and challenges philosophical positions that deny them. Moore insists that everyday beliefs carry a prima facie epistemic weight that must be overcome by any radical skeptical theory.
Moore's approach is both practical and argumentative: he presents common-sense claims as exemplars of knowledge and then shows that skeptical or idealist theories owe us stronger reasons to doubt what we plainly know. The force of his argument lies not in elaborate metaphysical construction but in shifting the burden of proof back to those who would reject ordinary knowledge.

Moorean Method
Moore introduces a distinctive methodological move now known as the Moorean shift. Rather than trying to dismantle skepticism by producing an internal logical refutation, he starts from what we know most firmly and then asks skeptics to show why those beliefs should be doubted. This reversal insists that philosophical theories must account for, and not lightly discard, the pre-theoretical certainties of common sense.
He often illustrates the strategy with concrete demonstrations, famously claiming "Here is one hand" and "Here is another" as a kind of proof of the external world. The demonstration is intended to show that the skeptic's universal doubt is less plausible than the straightforward evidence of ordinary perception. Moore thus treats epistemic priority as a decisive factor: when a philosophical hypothesis conflicts with a proposition that is more certain and better grounded in ordinary experience, the hypothesis is presumptively rejected.

Defence of Common-Sense Beliefs
Moore catalogs a range of everyday propositions, other minds exist, physical objects endure, the past is real, and regards them as known truths. He argues that such beliefs are not mere prejudices or naive errors but occupy the foundation of our epistemic system. Philosophical theories that deny these claims, Moore contends, must show not only that such denial is coherent but that it is more credible than the simple, direct knowledge we have.
His defense is partly epistemological and partly rhetorical: epistemological because he treats common-sense propositions as better supported than abstract skeptical hypotheses, and rhetorical because he foregrounds the implausibility of concluding that so many ordinary certainties are false. Moore does not pretend to offer an exhaustive philosophical proof of every common-sense truth; rather, he claims that the burden of disproof rests on those who would overthrow them.

Responses to Skepticism and Idealism
Moore confronts both skeptical skepticism, doubts about the existence of the external world, and idealist doctrines that reduce reality to mental phenomena. He argues that these views invert the normal order of justification by making abstract philosophical constructions trump immediate experience. For Moore, such inversion is unjustified: common-sense knowledge is simpler, more natural, and more secure than the convoluted arguments required to deny it.
He acknowledges that philosophers may find theoretical difficulties in reconciling certain ordinary statements with a systematic metaphysics, but insists that difficulty does not amount to falsity. If a philosophical theory requires rejecting things we know more certainly than the theory itself, the theory fails on pragmatic epistemic grounds.

Legacy and Limits
Moore's defence helped shape analytic philosophy by reasserting the importance of ordinary language and common sense. His method influenced later thinkers who explored the relation between ordinary belief and philosophical theory, and it remains a central touchstone in debates about skepticism and epistemic priority. The Moorean challenge persists as a tool for highlighting the intuitive implausibility of radical doubt.
Critics argue that the move can beg the question or fail to engage skeptical arguments on their own terms, and that asserting ordinary beliefs does not by itself provide the theoretical resources to answer deep epistemic worries. Nevertheless, the essay's insistence that philosophy must reckon with the certainties of everyday life has had a long-lasting impact on how philosophers approach skepticism and the aims of philosophical inquiry.