This chapter explores why we should think common sense has epistemic authority. First, it lays out exactly what common sense and the supposed epistemic authority of common sense amount to. It then assesses seven proposals that we find in the literature as to why common sense has epistemic authority. They say, respectively, that common-sense beliefs are irresistible; that there are no serious epistemic alternatives to thinking that common-sense beliefs have epistemic authority; that common-sense beliefs are certain, or at least more certain than any alternatives; that common-sense beliefs are instances of knowledge; that common-sense beliefs are vague and ambiguous and, therefore, likely to be true; that common-sense beliefs are the product of a reliable process of cultural evolution; and, finally, that God would not deceive us on such a large scale. The chapter argues that the first five answers are not convincing, not even jointly, but that the sixth answer is and that the seventh reply may well be combined with it.

What role does ordinary-language philosophy play in the defence of common-sense beliefs? J. L. Austin and Ludwig Wittgenstein each give central place to ordinary language in their responses to sceptical challenges to common-sense beliefs. But Austin and Wittgenstein do not always respond to such challenges in the same way, and their working methods are different. This chapter compares Austin’s and Wittgenstein’s metaphilosophical positions and shows that they share many metaphilosophical commitments. It then examines Austin’s and Wittgenstein’s respective takes on the problem of other minds and the problem of our knowledge of the external world. Interestingly, we find Wittgenstein employing methods more frequently associated with Austin and vice versa. Moreover, we find that a variety of defences of common-sense beliefs are compatible with ordinary-language philosophy.

This chapter argues for the following claims. (1) There is no content that groups the propositions of common sense together. (2) The common-sense grouping has a real purpose: it delineates propositions that we are at a very minimum justified in believing. (3) Common-sense propositions are to be found at the intersection of not-science-based yet widely held beliefs, beliefs not based on testimony or inference, and beliefs whose denials are pragmatically incoherent. (4) Commonsensicality is a graded concept: there are degrees in which propositions are propositions of common sense. (5) Propositions of common sense are objects of at least one of the following attitudes: belief, disposition to believe, or taking for granted in the sense of presupposing them, either as a justification-conferring presupposition or as a pragmatic presupposition. (6) Although we can give up common-sense propositions, we should only do so in the face of very weighty evidence.

The common-sense tradition holds that among the things we know are various facts about the external world and some epistemic facts – for example, that we know there are other people, that people know their names, and that we know that they know their names. This chapter makes two claims. First, that the common-sense tradition should include among the things known various common-sense moral claims as well as various particular moral claims that are no less evident. Second, that these moral claims are more reasonable to believe than any philosophical view that implies either that they are false or that we do not know them. In short, it suggests that the common-sense philosopher should treat some moral claims as having the same weight as some epistemic claims and claims about the external world. The last three sections consider some philosophical objections to this view. These include the objections that no evaluative claims are true or false, that we cannot know particular moral claims without knowing some general moral criterion, and that the appeal to our moral intuitions is illegitimate in philosophical inquiry.

In his 1925 paper ‘A Defence of Common Sense’, G. E. Moore set out his ‘Common Sense view of the World’ as a series of ‘truisms’ about himself and the world. Moore then claims (1) that our common-sense truisms are largely true, and (2) that we know that our common-sense truisms are largely true. In his writings Moore defends (1) against philosophers who argue that common sense is no guide to the nature of reality by distinguishing between the ordinary meaning of his common-sense truisms (which is unproblematic) and their analysis (which is often doubtful). He defends (2) against sceptics by arguing that the assessment of claims to knowledge has to respect the framework of deep common-sense beliefs which shape our evidence. This chapter argues that Moore’s defence of (1) is not persuasive but that the defence of (2) includes important contributions to epistemology.

A crucial methodological recourse in matters of deliberation and inquiry, common sense has a dual bearing. On the positive side, there is a strong pro-presumption that any answers we give to questions of policy and procedure shall incorporate and stand in confirmation with our common-sense beliefs on the matter. On the negative side, there is a strong con-presumption against any rejection or abandonment of common-sense beliefs, and a cogent justification should be provided for any step in this direction. Methodologically, the common-sense approach exerts a strong constraint on our procedures of explanation and validation. This chapter explores how we should think of methodology in common-sense philosophy. Common sense is neither a cognitive faculty nor a way of producing beliefs. A common-sense belief is not produced in a certain way but rather a particular sort of belief, that is, one that is available to people in general on account of its triteness, its palpable obviousness. A common-sense belief is pervasive among the members of a community on the basis of their shared experiences in managing everyday affairs. Common-sense beliefs address matters of everyday run-of-the-mill; they relate to what transpires within the sphere of the ordinary course of things in everyday life.