Uncertainty elicits more than one doxastic attitude towards God’s existence, namely agnosticism and fideism, which have very similar epistemic foundations despite the dissimilarity in their outcomes. This similarity mainly depends on the alleged uncertainty of evidence, and to disclose both attitudes in all their bearings, two fundamental theses, epistemic and practical, will be suggested. Employing these two theses, this study aims to investigate the crucial points where agnosticism and fideism overlap and diverge depending on the uncertainty and argue that the epistemic common ground, the basis of many criticisms of fideism, is self-destructive. The uncertainty concerning the evidence for God, ambiguity, or vagueness will be explored to justify this claim. This will bear the question of whether the evidence is ambiguous because it is absent mainly or because it is present but vague. Or is it neither absent nor vague but still ambiguous because both sides have clear evidence? Consequently, the current study shall object to the idea that agnosticism equals vagueness which implicitly means that agnosticism is a necessary stance and defends that fideism’s having loose or no relation to evidence is irrational.