AgnosticAntitheist
New Member
When theists are criticised for failing to provide evidence for their views, many are quick to respond that "absence of evidence is not evidence of absence". As catchy as this slogan might sound, I am afraid it is fallacious in the highest degree. In order to discuss this we need to define terms. Evidence is everything that can be used to establish the likely truth of a belief. Let us consider a statement A. Something is evidence for A if it increases the probability that A is true. Let us further consider a case where there is no such evidence for A as implied by "absence of evidence". It is obvious that the probability A has now is only the probability it has without evidence. So how can we determine it? There is a great amount of statements that are true. There is however an enormously larger amount of statements which are not. To get the odds that A is part of the former we need to divide the former by the latter. Since the former is way smaller than the latter the result is tiny. If the chance that A is true is tiny, it follows logically that the chance that it is false is huge, since any statement must either be true or false. We have shown that the absence of evidence leads us to high probability of falsehood and is thus evidence of such. We can conclude that the statement "absence of evidence is not evidence of absence" is wrong. Of course we haven't proven that something that lacks evidence is defnitely not true, but that isn't what is asked for.