Inspired by Four Horsemen identified by Greg Epstein (2007), Darwin, Marx, Nietzsche and Freud, in Good Without God: What a Billion Nonreligious People Do Believe and Massimo Pigliucci's (2010) exposition of the Pre-Socratic philosophers in Nonsense on Stilts How to Tell Science from Bunk,
Reason--it should be remembered--is as organic to humanity as instinct, intuition and emotion. Contrary to postmodernist notions that reason alienates us from our own desires, the person who is rational to a fault is a straw man. It is considered pathological to be entirely devoid of emotion and driven entirely by rational self-interest precisely because it is not normative.
The Freethought Argument: Reasonable Nonbelief
The existence of the gods is not self-evident. The burden of proof is on religion.
The Skeptical Argument: Lack of empirical evidence
The incorporeal is immaterial. Discovery trumps revelation.
The Secularist Argument: Inconsistent Revelations
Sectarian religions are mutually contradictory, internally inconsistent and incoherent.
The Humanist Argument: Evil
Things seem to happen for no reason. There is no cosmic will or plan. We make our own meaning.
Adversaries characterize antitheism as an appeal to emotion because religious harm has no bearing on whether the supernatural is real. It is a straw-man argument: religion is harmful therefore there are no gods. Religious harm is real, but it is a distinct from the question of supernaturalism. Even so, the ontological question has hardly been neglected by antitheists.
Philosophical antitheism merely calls for a recognition that not only is religious fundamentalism an impediment to human progress but that religious obscurantism is antagonistic to truth. While it does not mandate constant confrontation, the New Atheists have distinguished themselves by their tenacity. The tenacity of activists can manifest itself synchronically as intense confrontation, diachronically as determination to persevere to the end, or both.
There is something to be said for a live-and-let-live approach to religion. It certainly prevents a person from becoming overcome with anger. Those committed to truth and those committed to tolerance have competing claims to the moral high ground and people on both sides would be wise to avoid excessive sanctimony. We need firebrands and diplomats, each contributing as their talents and character suits the task at hand.