However, it is one thing to point to the general possibility of biological and cultural mechanisms constituting experience-independent sources of reliable knowledge, another to show that such mechanisms operate within philosophy. Even if there are areas of thought which rest on such foundations, this does not show that the intuitions of philosophers in particular have a similar backing. Moreover, there is arguably direct reason to doubt that they do. It is not just the intuitions of everyday people on philosophical matters that have a poor track record. The same applies to philosophers through history. It is not hard to think of deep-seated intuitions appealed to by past philosophers that have since been discredited. (A purely mechanical being cannot reason; space must be Euclidean; an effect cannot be greater than its cause; every event is determined; temporal succession cannot be relative.) In the next section we will see that there is reason to suppose that this unreliability is intrinsic to the nature of philosophy.