The following was too long for Counter Apologist‘s comment box so I have made it into a post! It is an unreflected discharge of my thinking on this subject in furtherance of his eagerly anticipated video.
I think trying to establish a perfect or absolute ontological basis for morality is a trap. Neither atheists not theists have established such a basis for morality, theists simply assert that there is one. What they do is create a false problem of “mere” social constructs. They try to get us to worry that without accepting that an absolutely objective foundation for morality exists, we must be arbitrary or dangerously subjective in our moral values and judgment. But how do they solve this problem? Not through the use of self-attesting truths like the moral absolutes, but by “intuition”. The common example is torturing a baby for fun. Theists do not establish that this is wrong, but simply accept it as “obviously” true, intuitively. This is not an objective moral system, it is the very definition of a subjective moral system. And of course such a system is useless for real moral dilemmas which is the whole point of morality, isn’t it?. Do I strangle my baby or let it cry and get us all killed by the Nazis? Do I take my kids to Disneyland or disappoint them and fix the roof? Real morality deals with situations like this where our intuition tells us that both are good. In fact, our intuitions often lead us to morally repugnant acts, revenge for example. Moreover, competing religions can say certain things are “obviously good” and have no objective basis to compare them. For some Muslims strict sexual segregation may be an obvious good, for liberal Christians, gay marriage may be. And, they cannot point to consequences of harm and well-being to convince each other, rather they must refer to their theology and intuition both of which are filtered through their own limited and sinfully corrupted nature!
Atheists are in the same boat (minus the presumption of sin-nature), we have intuitions too are ultimately the grounding of our morality. I think these are broadly classifiable into two categories 1) acts that further my interests or immediate goals (or biology) 2) acts that further my interests indirectly by supporting a healthy community or long-term goals. When these are in conflict, we have a moral dilemma. There may be an absolute perfect objective basis for these, to which we like theists are ignorant see skeptical theism) or they may be a result of evolution. There is an empirical and inductive basis to accept evolutionary founding, but I think we need to be clear that science has not proven this yet.
But even without a scientific basis or ontologically proven basis, we can still do better than “it is obviously good”. We can look to the most commonly, or universally held values, (well being, harm-avoidance, freedom to pursue idiosyncratic desires) we can accept that our moral basis is not ontologically supported (virtually nothing is, science included, i.e. the problem of induction). But what we can say is that this limitation only matters if we encounter people who genuinely do not share these values at all. We do not consider such individuals to be morally different, we consider them to have mental disorders or illnesses. They are called psychopaths, they lack empathy, or the capacity to understand the consequences of their actions. (Jon Ronson’s Psychopath Test is a must-read, the audio book is great and read by him!)
Even people who commit crimes based on theist delusions (Andrea Yates and, http://bit.ly/1jkeBSt) do not defend themselves on theistic grounds, they claim insanity.
In other words, to the extent there are limitations on the Moral Landscape-type moral system, it is limited only in applying it to the insane. Everyone else will have to accept reasonable arguments about well-being and harm and to this extent we can be objective about morality. It is nonsense to say that such an approach is arbitrary or dangerously subjective. If it were, our courts would be making decisions arbitrarily and subjectively all the time. They consider “objective” to mean what the reasonable person would do taking into account all of the relevant context. Courts never require ontologically established values.
So in conclusion I do not accept that it would be a problem if there were no absolute objective moral values, and even if there are, and they could be said to “exist”, neither theists nor atheists have access to them. We both use our intuition, which atheists (or humanists or SamHarrisians) can codify with reference to near-universally held values which only the insane would disagree with.
“The majority is always sane.” -Larry Niven