Never before have the critics of religion been as visible and as outspoken as they are today. People like Sam Harris, Richard Dawkins, and Lawrence Krauss reach huge audiences, and YouTube is a seemingly endless source of their debates with members of various religions.
However, most of them — empiricists that they are — keep a door open for the existence of a god, since negatives cannot be proven. To take a famous example: claiming that a teapot is orbiting the sun without any evidence may be irrational, but proving the contrary is impossible. As unlikely as the hypothesis may seem, empirical science can not preclude it with 100% certainty — absence of evidence is not evidence of absence. In other words, they cannot prove that god does not exist.
I think we can go one step further and close that last door with confidence.
The notion that a negative cannot be proven hinges on whether the corresponding positive can be proven. To take Russel’s teapot as an example: we cannot prove that it’s not orbiting the sun somewhere, because it’s impossible to look everywhere at the same time. Therefore we say that we don’t have evidence for its existence, but we cannot be certain of its non-existence either, because a single positive observation would settle the case. However, if no methodology could exist to positively prove the teapot’s existence, we could be absolutely sure of its non-existence.
I will argue that god, or any other supernatural entity for that matter, is exactly like that: it’s a teapot that cannot possibly be proven to exist, and therefore there’s no need to disprove its existence in order to be sure that it does not exist.
The heart of the issue is the concept of the supernatural itself. Metaphysically it seems impossible to define the supernatural in any meaningful way. Any definition of the term has to rely on using its antithesis — the natural — in some form or another, since that is all we know. However, this makes the term supernatural synonymous to non-existence, since everything we gain knowledge about by definition moves into the realm of the natural, or simply the existing.
Any god or any supernatural phenomenon has to have some kind of effect on the natural world — something we can perceive or measure — in order to be relevant at all. Once something has an effect on the natural world though, it has, figuratively speaking, by definition moved from the supernatural to the natural world.
With this conceptual line being crossed, the previous attribution to the supernatural is lost. We wouldn’t call anything measurable in the natural world a god. To the contrary, we would investigate it as a natural phenomenon.
This is precisely why we can close the last door with 100% confidence: There cannot be a positive proof for the existence of a god, because no proof for anything supernatural can exist. Having proof for something automatically moves that thing into the natural realm, stripping its status of being supernatural. A god for which we would have proof wouldn’t be a god.
Any god — and anything else called supernatural for that matter — is a self-contradictory concept. It has been defined out of existence from the very beginning.
So keep closing the doors.