Reply #187: It's meaning is context specific and person specific.

[ozone_man]

We may require a different level of certainty when refering to the light switch then we do towards life and death situations like crossing traffic. Yet generally when we say we are certain, we do not require proof. We'd not get much done in life if that were the case.

The strong atheist positively asserts, at the very least, that no deities exist, and may go further and claim that the existence of some or all gods is logically impossible.

http://en.wikipedia.org/wiki/Strong_atheism

In a similar way we can say we are certain that no gods exist without having 100% positive proof, in the same way that we might say that we are certain there are no pink unicorns or fairies. We cannot prove there are no fairies, but it's reasonable to say that we certain they don't exist. If I see some evidence of fairies, then I may change my mind, but until then, I choose to believe or know that they don't exist.

Also,consider that science assumes that something is false unless proven otherwise. The burden of proof is on those making extraordinary claims. Extraordinary evidence is required to support extraordinary claims, and there is no evidence whatsoever to support the existence of God.

Practically speaking, I think there are more than simply weak or strong atheists. There are those in between, who don't assert there are no gods, nor do they simply not believe in them. I fit somewhere in there, but closer to the side that asserts that they don't exist, but in a practical way, as I assert that fairies don't exist.