>morality is objective (like gravity) or subjective (like art).

Your false dichotomy strikes at the core of the conundrum. Morality is objective like consciousness, undeniable regardless of whether it is quantifiable. It is fashionable to assume and insist that gravity is absolutely objective and art is entirely subjective, but the truth is not that simplistic.

>Morality is a process now? How does that track with the gravity analogy?

It shows your reaaoning to be a matter of assuming a conclusion, namely, that if morality cannot be simplistically quantified then we should presume it doesn't exist. As if works of art stop existing for those who proclaim "that isn't art!"

I could belabor the point further, identifying how gravity is not directly quantifiable, but can only be measured in terms of mass and acceleration. Does this mean gravity is not real? In some ways, it actually does, in some ways, it doesn't.

>I never said morality was quantitative,

Is there some other way of interpreting "gravity can be measured" that I'm not aware of? Perhaps you don't want to admit it, but the premise that morality must be quantitative like gravity in order to exist is clearly the foundation of your contention.

>but you compared it to a phenomenon that could be.

I used an analogy. It is a kind of comparison, but relies on a level of engagement you haven't provided.

>"Recognizing" morality suggests that, like physics, it exists independent from "moral agents."

It does more than suggest that, it declares it directly. It is a necessary presumption that anything we percieve exists independently of our perceptions if it exists at all. Some people believe that they can be amoral intellectual agents without being moral agents, and if they try hard enough they can refuse to recognize morality at all. It is an easy assumption to make, because of the nature of morality (including the ways it differs from time, mass, velocity, momentum, and gravity, though all of these things can be considered useful analogies for understanding what morality is) but it is a mistake nevertheless. To be conscious is to recognize moral truths, despite any difficulty we might have expressing, describing, or comparing them.

>If we agree that the existence of moral agents is a necessary precondition of the existence of morality,

We don't. In fact, you have it backwards, that is the opposite of what I directly said. The existence of moral agents is a necessary precondition for observing the existence of morality, but not for that existence to occur. The existence of morality is a necessary precondition for the existence of moral agents, but recognizing morality is not a precondition for its existence, just as recognizing gravity as gravity is not a precondition for gravity. Gravity is quantifiable even when it isn't quantified.

>are you saying that there is some universal standard of morality

Apart from "morality exists", no standard, universal or otherwise, is necessary for morality to exist.

>but that did not exist until human evolution passed the "moral agent" threshold?

You keep repeating the same error. Morality exists independently of moral agents, but can only be observed by moral agents. Perhaps "time" would have been a better analogy than gravity? Any analogy would suffice if you were interested in understanding it, but no analogy could suffice if you are not.

Thanks for your time. Hope it helps.