That doesn't follow. You can't lack believe in something unless it actually exists?
If a kid believes in the tooth færie, does she then exist?
Everything exists. Whether actually, imaginatively, extrapolatively, reductively, deductively, or inductively, everything exists.
The default position is the factory setting; the belief you were born with. Were you born with a belief? any belief?
No? -- Then you were born without belief; an atheist. Atheism is the default; the mental blank slate we all start with.
I disagree that the
default position is the position "you were born with." More according with science and common usage, the term refers to what the steady state is if you do not change it. That applies to any point in your lifetime.
I agree that it takes a push to go from someone without beliefs to someone with beliefs, but it's a stretch to suggest that that person is an infant.
The default isn't a belief in nothing. It's no belief at all. It's the state you were born in.
You were born with beliefs--at very least, the five senses. At best, a belief in "mother" who will nourish you and keep you safe. To suggest that we are born without beliefs is to deny what "
belief" means (the conviction of something being true).
If you want to argue it, then I would propose that the point at which we garner beliefs is the point at which we start investing in things being true.
Evidence is evidence. That's all it equates to. The choice to derive a belief from it is another matter.
Note that S.D. referred to "rational reasoning" derived belief. Now, a lot of people hold non-rational beliefs, derived from insufficient evidence, but he cited rational belief, derived post hoc, from sufficient evidence.
It's not possible to accept/invest in {something being true} without evidence. Otherwise, it's not belief.
Now, I know words get substituted all the time, and it's not a stretch to substitute 'belief' for trust, extrapolation, expectation, even reasoning, but it's not those things. It's just the acceptance of {something} as true.