Why do Athiests require 'proof' that God exists?

[Ryft]

Likewise for Christianity. Evangelicalism and most mainline denominations stress orthodoxy or right belief because belief alone is considered by them the only means of salvation.

My views are largely consistent with the Presbyterian church, which is a mainline denomination, and the evangelical movement within Christianity. My library consists of a great deal of literature influenced by these traditional views, including confessional documents (Westminster Standards, and Three Forms of Unity), theological textbooks, and systematic theologies. So when I read this statement by you my first impression was, "Wait, where is it said, in such sources, that belief alone is the only means of salvation?" That actually contradicts the views expressed in evangelicalism and at least the Presbyterian mainline denomination, where the only means of salvation is Christ alone—not belief alone. As Benjamin Warfield put it (a Presbyterian): "It is not faith in Christ that saves but Christ that saves through faith." With respect to salvation, faith is instrumental but it is not causal. Christ alone is our only means of salvation. "I am the way, and the truth, and the life. No one comes to the Father except through me" (John 14:6). "There is salvation in no one else, for there is no other name under heaven given among people by which we must be saved" (Acts 4:12). It is Christ, not faith, that saves.

I think this is backwards. Truth alone when not coupled with the desire to do good and the cultivation of virtue has no practical value.

You are not alone, for biblical Christianity also teaches that "faith, if it does not have works, is dead, being by itself" (James 2:17). Just as Paul said that works without faith is useless, so James said that faith without works is useless. In other words, salvation is through faith alone but that faith is not itself alone; for a faith that is alone or by itself is a dead faith. A living and salvific faith, being a gift of grace from God (John 6:65; Acts 18:27; Php. 1:29), always bears fruit or produces works, "for the one bringing forth in you both the desire and the effort—for the sake of his good pleasure—is God" (Php 2:13; cf. 1:6). "For we are his workmanship, having been created in Christ Jesus for good works that God prepared beforehand so we may do them" (Eph. 2:10; Heb. 13:21). "You did not choose me, but I chose you and appointed you to go and bear fruit, fruit that remains" (John 15:16). In other words, there is no orthodoxy without orthopraxy. So John Gill: "For as works without faith are dead works, so faith without works is a dead faith." And Matthew Henry: "A bare profession may gain the good opinion of pious people ... [But here it is plainly shown] that an opinion or assent to the gospel, without works, is not faith." And so on.

The scientific method doesn’t operate in a philosophical vacuum. Philosophy plays a significant role in both establishing methodologies (Popper) and the interpretation of results.

For the latter point I would suggest Thomas Kuhn, The Structure of Scientific Revolutions, 3rd edition (University of Chicago Press, 1996).

Without supporting proof, my position is a proposition may not be claimed to be true. Period.

This is what we call a self-stultifying statement, that is, a statement which defeats itself.