The concept of truth, i.e. the idea that statements and beliefs express propositions that correspond to reality, cannot be accounted for in the absence of God. Why is that?
First, let us consider the fact that we cannot determine if it is at all possible for propositions to correspond to reality unless we already are in possession of a concept of truth by which to judge this. Said in another way, we cannot determine if truth exists unless we already pressuppose the truth of a certain concept of truth. Thus, the conclusion so far is that truth is axiomatic. It cannot be denied, because in order to deny it we have to first presuppose it. So which worldview can account for the concept of truth?
The Vedic scriptures state that the concept of truth is revealed by Krishna as innate knowledge, i.e. we are created with the knowledge that something is true and something is false. In other words, Krishna has revealed that it is true that truth exists. Krishna is omnipotent, so it is axiomatic that He has the power to reveal perfect, infallible knowledge to us in such a way that we know it to be true.
In contrast to the monotheistic Vedic scriptures there is no naturalistic way to account for the concept of truth, and, by implication, the existence of knowledge. Atheists are without explanation as to how inert matter can generate knowledge-producing epistemic faculties. After all, in the absence of God our brain is not rationally designed; it originated from wholly irrational causes. Our mental faculties, including our epistemic faculties, survives simply because they are sufficient for survival, not because they are able to aquire knowledge of reality (at least we would not be able to determine if they could). Hence, on atheism we are not able to determine to which degree (from zero to the highest) our epistemic faculties can acquire knowledge.
Atheism – if it could be true (which it cannot) – is thus a worldview in which we cannot rule out that our epistemic faculties – in all cases – gives us zero degree of certainty.