  Plausibly, there are some propositions whose truth or falsity we grasp in an utterly direct, unmediated way. Consider, for example, simple arithmetical truths such as the proposition that 2+2=4. Traditionally, such truths have been held to be ‘self-evident’; allegedly, they need only to be understood in order to be known. If the truth value of every proposition were transparent in this way, perhaps we would have little or no need for evidence. In contrast, a central function of evidence is to make evident that which would not be so in its absence.