In fact, certainty exists in very different modes. The kind of certainty afforded by a verification that has passed through doubt is different from the immediate living certainty with which all ends and values appear in human consciousness when they make an absolute claim. But the certainty of science is very different from this kind of certainty that is acquired in life. Scientific certainty always has something Cartesian about it. It is the result of a critical method that seeks only to allow what cannot be doubted. This certainty, then, does not proceed from doubts and their being overcome, but is always anterior to any process of being doubted.