"The existence of a god does not solve the problem because we need some reason to conclude that the god is good."
This is a proof for god, not a proof for morality. the Premise is that moral right and wrong exist. From that premise, we reason to the existence of (a moral) god.
"One solution, the one that strikes me as the least unsatisfactory, is to posit the existence of moral truths analogous to physical truths, perceived by a moral sense analogous to physical sight or hearing. That describes the world as almost everyone actually perceives it—there are not many people who do not see torturing small children for fun as wicked. And that view of moral reality can be confirmed in the same way we confirm our view of physical reality, by subjecting it to consistency tests."
How do you square that position with, what seems to me anyway, to be huge amount of evidence against it.
I am assuming you believe racism is immoral, slavery is immoral, and homosexuality is moral, or at least morally neutral. And I'm also pretty sure (please tell me if you disagree) that for most of human history the vast majority of people believed the opposite.
If your theory is correct, why did the majority of humanity fail to perceive these moral truths until recently?Second:
"One solution, the one that strikes me as the least unsatisfactory, is to posit the existence of moral truths analogous to physical truths, perceived by a moral sense analogous to physical sight or hearing."
This analogy illustrates another problem I have with your position. In what sense are moral truths "true" if there is no god to enforcement them. Yes government, culture or other private mechanism can play a role in enforcing standards. But in what sense does a moral "truth" exist if these mechanisms fail to enforce it.
An example to make this more concrete. Let's agree for a second that theft is immoral. Suppose a thief steals throughout his life, is never caught, and feels no remorse.
What consequence flowed to the thief for violating a this "moral truth"? I'm getting out of my depth here, but as I under physics, for example, the laws apply consistently and universally. Setting quantum mechanics aside, if Wylie Coyote goes over the cliff, he doesn't occasionally float in the air; he invariably falls to the ground (probably not strictly true in quantum mechanics, but true enough for our purposes).
Doesn't moral truth, like a physical truth, suggest some sort of natural consequence that flows from running afoul of the principle the truth espouses? What would that be in the hypothetical I pose? And if there is no consequence, in what way was it wrong for the thief to behave the way he behaved? He maximized his utility, even if you and I believe his utility function is defective.
(I would love for you to debate Peter Kreeft.)