Positive atheism is defined as the positive claim that no gods exist or the denial that the claim "at least one god exists" is false. This definition of positive atheism is often confused with the definition of atheism generally but that is a mistake; the definition of positive atheism is a subset of atheism generally and closely parallels related terms like strong atheism. There is also some overlap with explicit atheism and critical atheism.
The term positive atheism appears to have been first used in this sense by Antony Flew at least as early as 1976 and has become common in philosophical, scholarly writing on atheism and theism. Positive atheism is in fact far more common among philosophers than related terms like strong atheism, but strong atheism is more common among laymen and popular writers.
"Negative atheism, the position of not believing a theistic God exists... Positive atheism: the position of disbelieving a theistic God exists... Clearly, positive atheism is a special case of negative atheism: Someone who is a positive atheist is by necessity a negative atheist, but not conversely."
- Michael Martin, Atheism: A Philosophical Justification
