Well, Buddhists are 'non-theists' — Wayfarer

there are plenty of theist Buddhists.

no, i don't know the percentages, but willing to assume than Siddartha - living 2500 yrs ago was a "theist" (Hindu for sure).

as of course Jesus was a Jew.

My own judgment is the source of moral fact. If your moral opinions do not align with mine then you are wrong. If I judge an action to be wrong then it is objectively wrong. If you are unsure or concerned with whether an action is wrong or not, just ask me and I'll give you the answer.

But ultimately Buddhist ethics are grounded in the reality of karma - that all intentional actions have consequences — Wayfarer

Hindus also affirm this theology.

Question for non-theists: What grounds your morality?

Implicit here is that theists's morality is grounded in some special way - presumably better, in some sense - that the morality of non-theists is not or cannot be. Please accept or reject the implication, and if you accept it, please defend/explicate it. That is, make clear what that special way is, and why it's special.

I, myself, reject the implication. The title of the OP could just as well have been, and arguably should have been, simply, "What grounds your morality?"

Since there is no widely agreed theistic morality, nor coherence about the definition of god, it begs the question WTF grounds morality if you are a theist?
What's your source?

ultimately subjective, for whose reason are we speaking of? And human reason, limited as it is, cannot construct moral laws — Modern Conviviality

What limit do you put on human reasoning??
It is a theist human reasoning "limited as it is" that has him believing in his "God". If it was not his human reasoning that led him to his belief in his god's dictated morals then why was it his particular "god" that he choose to follow rather than the many others gods that have been portrayed in men's script?

I've never understood why morality is the kind of thing that needs a ground or foundation. If you have an ethical system, it gets tested against intuition and ethical problems in the abstract. I view this as similar to axiomatising arithmetic to 'found' it, if the foundation didn't contain or imply already established arithmetical truths, it would be discarded - rather, it is judged a good axiomatisation when it at least produces the right theorems. In this sense, the expected theorems are more primordial than the axiomatisation.

If a theory that grounds morality, whatever that means, is to have relevance to ethical concerns, it will be tested for its ethical implications and either found fortuitous or unfortuitous depending on its treatment of the ethical issues within its scope. If we would use our intuitions in ethical problems and real life scenarios to judge derived moral statements from a grounding theory and that theory's rightness - be these derived entities a product of ratiocination or sensibility; is it really the theory which is logically prior, or the embodied practice of ethical decision? And if we already have the capacity to evaluate ethical decisions, to live ethically, can it be said that a grounding moral theory provides anything more than a set of heuristics to judge how to act and how to live in the abstract?

I've never understood why morality is the kind of thing that needs a ground or foundation. — fdrake

Presumably it's the Principle of Sufficient Reason. Why is something right or wrong?

And if we already have the capacity to evaluate ethical decisions, to live ethically, can it be said that a grounding moral theory provides anything more than a set of heuristics to judge how to act and how to live in the abstract? — fdrake

I suppose it's a way to avoid relativism. What if my ethical intuitions differ from yours? Do we simply accept the difference, or do we claim that one or the other of us is wrong? If the latter then we need to look to something other than our intuitions, else it's nothing more than a battle of he said/she said.

Asking why something's right or wrong doesn't require believing in the necessary existence of a sufficient justification, only that to satisfy the questioner there will be a sufficiently persuasive justification for them. If someone could not possibly be convinced by any explanation they're playing a different game than 'explain to me why this is right (or wrong)'.

An emotivist who believes all ethical statements are power plays or persuasive expressions of raw sentiment, or a cognitivist who beliefs that 'moral statements' are truth apt, perhaps can be arrived to by reason and are either true or false (or all false) will still have to act ethically and be effected by the ethical as a normative-juridical structure. They will face similar trials and tribulations in life irrelevant of whatever extraneous philosophical apparatus they're hedging their bets with. They will, usually, try to do what's right and if not that try to do what they can reasonably get away with. They will have been doing all of that, thinking ethically, acting ethically for a long time and will surely have been effected by the ethical dimensions of life since their birth.

Believing that there is some extraneous, foundational philosophical apparatus that will vouchsafe anyone's moral choices completely divorces the ethical from the political - how to conduct ourselves and what should we, as a collective, strive for. Leaving the ambiguities in - some things are right, some things are wrong, maybe there's no ultimate ground, maybe there is an ultimate ground, not only provides a more accurate catalogue of our approaches to morality, but keeps the ethical and the political together. To do what's right is to negotiate with the world around you; sometimes even from the ground up.

Asking why something's right or wrong doesn't require believing in the necessary existence of a sufficient justification, only that to satisfy the questioner there will be a sufficiently persuasive justification for them. If someone could not possibly be convinced by any explanation they're playing a different game than 'explain to me why this is right (or wrong)'. — fdrake

If the answer to the question is just persuasive and not explanatory then it's sophistry. Some (especially moral realists) will want more than that.

One way of being persuasive is to provide a good explanation and be right!

According to Moral Foundation Theory, I (atheist) have an unusually high reliance on the senses of care/harm and fairness/cheating, and a much lower reliance on the senses of loyalty/betrayal, authority/subversion, and sanctity/degradation. Basically the profile of a progressive liberal, according to the theory.

A theist will generally rely more on loyalty, authority, and sanctity, giving them a broader and more balanced moral framework, the primary benefit being more cohesive and successful social groups (not necessarily societies).

I'm an atheist. I'm not an ethical objectivist.

Everyone really grounds their morality in subjectivity--the way that they feel about interpersonal behavior, basically. That's the case even if you're a theist or ethical objectivist. You simply have incorrect beliefs in those instances. What's really going on is that your ethical views are grounded in how you feel about interpersonal behavior.

Morality is ontologically groundless. Anyone who thinks otherwise is deceiving themselves.

This is an ontological, not an epistemological question about ethics. I am aware atheists can be very moral beings.
- This is a question for non-theists who hold to objectivity in ethics (moral realists) - e.g. it is always true that murdering someone for no reason is morally wrong, etc.
- Grounding morality in: evolution (naturalistic fallacy), sentiment (subjectivity), or human reason (ultimately subjective, for whose reason are we speaking of? And human reason, limited as it is, cannot construct moral laws) seems incoherent. Short of Platonism, are these all the options a non-theist has at his disposal? — Modern Conviviality

Humans have the capacity to make moral judgments. These judgments are rooted in empathy, the feeling invoked when considering the condition of others. We don't have to be taught that it's"wrong" to cause another pain and suffering; we literally feel it to be so - if we function properly (sociopaths do not function properly). That act x is wrong is a semantic description of our natural empathy-based sensation of wrongness. It is a properly basic belief, and not mere opinion because we have the belief innately. The belief/feeling is analyzable and seen to be consistent with the survival and thriving of our species. So the ontic fact to which the proposition "x is wrong" corresponds is: the ingrained empathetic feeling in conjunction with the objective benefit to the species of a proper moral judgment.