However, if we can't trust our belief-forming faculties to tell us the truth about God, why should we trust them to tell us the truth about anything
This is such a lousy argument. Seriously, "If our first wild guessed ass-grab explanation is wrong, why should we trust any explanation about anything ever?" Well, because other explanations have proof, logic, and real world application backing them up. That's why we trust them. Arguments with proof get trusted; arguments without proof get discarded. We believe in evolution because applications of evolutionary theory lets us create evolved semiconductors via artificial selection, and every time we develop a new application it's another reason to believe.
If you look closely, Keller's argument doesn't even directly address evolution. It's a slight of hand in the wording to make you think it's about evolution. In actuality, this is a fully general argument against using reasoning to change society's mind about anything ever. "If we were wrong about , we can't use reason to change our minds about ." This is basically the exact opposite of human history. I'm imagining two Roman philosophers arguing and one of them saying that Apollo's chariot has to be the literal sun because if they were stupid enough to believe that they're too dumb to figure out the truth anyways.
Our guessing wrong about God doesn't prove shit. Starting from the dawn of time, humans have been wrong about pretty much everything. Fire doesn't come from the Gods. There's more than four elements. The Sun doesn't revolve around the Earth. Sickness isn't caused by bad spirits or an imbalance in the humors. The moving at the sound barrier won't crush any material to paste. Atoms aren't indivisible. Artificial Intelligence won't take about a month. etc. You name it we've been wrong about it. Being wrong about God doesn't disprove our ability to reason. It's just another thing we've been wrong about in the long, long, long, long line of things we've been wrong about. And yet, we keep reasoning. And little by little, year by year, we keep using our reasoning to help humanity become less wrong.
P.S. You don't necessarily need to read the sequences in order. I personally skipped the Quantum Physics sequence and came back to it later. If you're interested in Evolutionary Psychology, just read the Evolution Sequence.
So, a little background- I've just come out as an atheist to my dad, a Christian pastor, who's convinced he can "fix" my thinking and is bombarding me with a number of flimsy arguments that I'm having trouble articulating a response to, and need help shutting down. The particular issue at the moment deals with non-theistic explanations for human psychology and things like love, morality, and beauty. After attempting to communicate explanations from evolutionary psychology, I was met with amused dismissal of the subject as "speculation".
There's one book in particular he's having me read- The Reason for God by Timothy Keller. In the book, he brings up evolutionary psychology as an alternative to theistic explanations, and immediately dismisses it as apparently self-defeating.
"Evolutionists say that if God makes sense to us, it is not because he is really there, it's only because that belief helped us survive and so we are hardwired for it. However, if we can't trust our belief-forming faculties to tell us the truth about God, why should we trust them to tell us the truth about anything, including evolutionary science? If our cognitive faculties only tell us what we need to survive, not what is true, why trust them about anything at all?" -Timothy Keller
The obvious answer is that knowing the truth about things is generally advantageous to survival- but it hardly addresses the underlying assertion- that without [incredibly specific collection of god-beliefs and assorted dogmas], human brains can't arrive at truth because they weren't designed for it. And of course, I'm talking to a guy with an especially exacting definition of "truth" (100% certainty about the territory)- I could use an LW post that succinctly discusses the role and definition of truth, there.
Another thing Dad likes to do is back me into a corner WRT morality and moral relativism- "Oh, but can you really believe that the act of rape doesn't have an inherent [wrongness]? Are you saying it was justified for [insert historical monster] to do [atrocity] because it would make him reproductively successful?" Armed only with evolutionary explanations for their behavior, I couldn't really respond- possibly my fault, since I haven't read the Morality sequence on account of I got stuck in the Quantum Physics ultrasequence, and knowing that reality is composed of complex amplitudes flowing between explicit configurations or aaasasdjgasjdga whatever the frig even (I CAN'T) has proven to be staggeringly unhelpful in this situation.
In addition to particular arguments WRT the question posed, I could also use recommendations for good, well-argued and accessible books on the subject of evolutionary psychology, with a focus on practical experimental results and application- the guy can't be given a book and not read it, so I'm hoping to at least get him to not dismiss the science as "speculation" or a joke. It's likely he's aware that the field evolutionary psychology is really prone to hindsight bias and thus ignores it completely, so along with the book, a good article or study demonstrating the accuracy and predictive power of the evolutionary psychological model would be appreciated.
Thanks!