Proofs relying crucially on computers provide less certainty than do proofs not requiring computers  Human cognition alone cannot verify computer-dependent proofs; such proofs can never provide the degree of certainty that attends our judgments concerning, for instance, simple arithmetical facts, which can be verified by human calculation
Of course, in these cases one often uses electronic calculators, but here the computer is a convenience rather than a supplement to human cognition
It is impossible to supplement the cognitive abilities of humans by means of artificial devices such as computers.