DG-

No, that's definitely not what I am saying. I believe that logic, math, science, and indeed morality too, are all objective, and hence are not human constructs. We discover true logical, mathematical, scientific, and moral propositions; sometimes it's difficult, there is some disagreement, it's a work in progress, but there is something objective out there that these true propositions refer to.
On the contrary, I think they do have ontological value; when true they represent facts about objective reality.

Yes, well, I assumed you understood where I was coming from, so I didn't preface it with "in a purely naturalist (atheist) universe..." Still, thanks for that answer.

The thing is, you are actually asserting the existence of a supernatural, universal reality on which human knowledge is contingent, and the supernatural part is just gratuitous. Well, okay, I could echo other people in this thread by saying: back it up. because it seems to me that things like a changing zeitgeist, changing physical models, the waning and waxing of compassion or hate in our societies, and so on, against the backdrop of "the universe" seem to lend more support to the notion of human constructs. I mean, in what way are justice, love, logic, cruelty etc. universals? Show me an instance of justice among the moons of Saturn. Or love. It just doesn't make any sense outside of human interaction. But I feel dumb even bringing it up again.

The whole argument against scientific naturalism reminds me of a teenager who just saw The Matrix for the first time, or a student who heard his first philo 101 lecture. "Hey dude, did you know that nothing is real?! It's all an illusion." Fair enough, that's a position that cannot be disproved by definition, but it also doesn't allow any conclusions concerning the nature of nature, super- or otherwise. :)