Quite right, you said that it is obviously dependent on human opinion. I drew the inference that it was thereby subjective -- I still think that's a reasonable conclusion, but no need to dwell on that point.
Sorry if you think I misrepresented you. It was unintentional.
Again, I agree there are differences. I was simply pointing out that your particular argument applied to things that we don't regard as depending on human opinion.
OK, well the above is more-or-less OK (and I was not worried about anyone misrepresenting me).
(Premise) The only known opinion ever expressed about any such notion as "morality", objective or otherwise, is an opinion voiced only by humans.
(Premise) No other known living things, have ever expressed any such notion.
(Conclusion) [paraphrased] Morality cannot be independent of human opinion.
As stated, you can replace the word "morality" with more or less anything, and the two premises above are still true.
I don't think we need to dwell any further on this. My criticism was simply over the particular form of the argument originally stated.
But here (in the above quote) I think the "conclusion" is wrong.
Something called "morality"
might be independent of human opinion (as indeed WLC claims it is when claiming specifically"
objective" morality in humans), providing there was genuine evidence for it's existence as something quite separate from mere human opinion or human claims (for which, see "2" below).
However, afaik, there is no evidence of something called "
objective morality" (the objective part is the part we are specifically concerned with according to WLC), that is anything other than that self-same human opinion that
pharphis said was
"defined by (human) theists as independent of human opinion".
I think that would be a circular argument if theists such as WLC are actually saying (as pharphis said) that
"as human theists, such as WLC, it is our opinion that something called objective morality exists in humans, and we define that as being independent of our own human opinion, that being the same human opinion that we just used to create the concept of "objective human morality" in the first place!".
Just for the sake of additional explanation, two additional comments -
(1) it might be possible to construct a very loose definition, or a generalised description, of what is usually meant by most people by the word "morality", e.g. compassionate behaviour from one animal towards another. But afaik traits like that are also shown by other animals, and not just by homo sapiens. And afaik, those traits can quite easily be explained as adapted behaviour related to evolution. So that is quite different from claiming "objective morality, implanted in humans by God".
(2) also, it might not be a circular argument for theists such as WLC to claim that
"objective morality is something defined as independent of human opinion", providing they can show that their definition is not actually "dependent on their own human opinion", i.e. if they can show entirely independent evidence for the existence of "objective morals, placed in humans by God" ... in your analogy with gravity, scientists have shown that what we call "gravity" is indeed entirely independent of human opinion .... whereas WLC has not shown that his notion of "objective morality" is independent of his own subjective human opinion.