Atheism is a lack of belief in gods or a rejection of the belief in gods, typically due to insufficient evidence or logical reasoning. It is important to note that atheism does not necessarily claim absolute certainty that no gods exist; rather, it generally asserts the absence of belief until convincing evidence is presented.
The argument you mentioned is often referred to as the "god of the gaps" argument, where the gaps in scientific knowledge are attributed to the existence of a deity. However, it is crucial to recognize that positing something exists outside of space and time is a speculative claim that lacks empirical evidence or logical support.
Science is a methodological approach to understanding the natural world, relying on observation, experimentation, and the formulation and testing of hypotheses. By its nature, science is limited to investigating phenomena within the realm of space and time. If something exists outside of space and time, it becomes challenging to subject it to scientific inquiry or empirical investigation.
Therefore, the claim that gods exist outside of space and time is not verifiable or falsifiable using scientific methods. Atheists often base their lack of belief on the absence of empirical evidence supporting the existence of gods within the natural world.
It is worth noting that different atheists may have varying reasons for their lack of belief, and not all atheists hold the same viewpoints. Critical thinking, skepticism, and a reliance on empirical evidence are common factors that inform atheist perspectives.