How can atheists say for sure theres no god?”
Most atheists don’t assert that no gods exist; only a subset of all atheists are also “strong” or “positive” atheists. In fact, most atheists identify primarily by their lack of belief in gods, rather than the belief claim that none exist. The terms “strong” and “weak” in this context are not referring to the level of fervor or conviction one has concerning atheism. They are indicative of whether or not the person is making a gnostic belief claim or not (see above). Weak atheism makes no gnostic claim. It is simply the lack of belief in any god. Monotheists share the same lack of belief in gods, except for the one they do believe exists. Weak atheism is the de facto position of the majority of atheists today. Strong atheism is weak atheism plus a gnostic belief claim: a strong atheist asserts with certainty that no gods exist. All atheists are at least weak atheists; a subset of those are also strong atheists.
