In a world of atoms and void, there are no universal concepts
If the same thought pattern shows up with only minor variation among the vast majority of members of a population, that should qualify as a universal.
Here-again betraying my own lack of technical training, I want to repeat that I (and I bet I am far from the only one) find this topic very confusing and off-putting due to the common meaning the word "universal" seemingly in conflict with the way philosophers use it. For example from the Internet Encyclopedia of Philosophy:
Universals are a class of mind-independent entities, usually contrasted with individuals (or so-called "particulars"), postulated to ground and explain relations of qualitative identity and resemblance among individuals. Individuals are said to be similar in virtue of sharing universals. An apple and a ruby are both red, for example, and their common redness results from sharing a universal. If they are both red at the same time, the universal, red, must be in two places at once. This makes universals quite different from individuals; and it makes them controversial.
MIND-INDEPENDENT ENTITIES ..POSTULATED TO GROUND AND EXPLAIN RELATIONS....?
And in the quote it is considered acceptable to compare an apply and a ruby and to say both are red and on the strength of two instances of something similar call that similarity a "universal?"
The reason I quote Godfrey is that that is how I tend to look at the question, although at present I would vary that and say:
"In a universe in which atoms are the only eternally unchanging entities, there is no possibility of there existing eternally unchanging human concepts (which is what is IMPLIED, to a normal person, by the word "universal").
On the other hand I agree that Martin is stating something obvious too:
"If the same thought pattern shows up with only minor variation among the vast majority of members of a population, that should qualify as a universal."
I personally just find it very confusing and potentially very misleading for philosophers to to try equate "same thought pattern"... among "members of a population" and call that a "universal" (which again to me implies that it is presumed to be found in ALL members of that population anywhere in the "universe" (meaning "cosmos").
I just wanted to restate this because I find it maddening that philosophers want to insist on using that term "universal." I find it impossible to shake the idea from my mind that this is intentional deception on the part of people (Plato et al) who want to postulate and convince untrained people of something that does not really exist. Of course I have no idea who originated the term "universal" and presume it is more modern in origin.