II. Let's put aside for the moment the fact that there are serious problems with the idea of God as a source of morality. (See, for example, the Euthyphro Dilemma.) The charge is wrong from the get-go because it misunderstands what morality is. Morality is a fundamental part of human social life--it never was a metaphysical set of commands. In the words of philosopher Patricia Churchland2, it is a "constraint-satisfaction problem" our brains solve: we have different needs and wants living within a society, and morality is the necessary way to balance them.
We are profoundly social creatures, wired to cooperate and flourish in a society. Indeed, cooperating with others has been found to activate pleasure and reward areas of the brain3. Interacting pleasantly with others is fundamental to who we are, and we need to belong with others: over a range of studies, the pain of social exclusion has been shown to activate areas of the brain associated with physical pain4,5. Moreover, social support is linked to many positive outcomes, including physical health6. (Of course, no one but theists in the heat of argument needs this research cited: would you rather go for coffee with your best friend or stab your best friend in the back over $100? Even if you are religious, does your answer have anything to do with God? If you were an atheist, would YOU now want to kill a person for monetary gain?)
Social and moral intuitions run deep: research has found that infants as young as 5 months old prefer a helper to a harmer7. Moreover, our empathic capabilities are impressive: when we see a relevant other in pain, overlapping emotional brain regions respond as when we are in pain8,9, and we feel motivation to respond. Descriptively, we have strong natural moral intuitions that guide us.
III. Prescriptively: The point is, we are very social creatures, and as social creatures, we need cooperation and trust. We all desire to live well and flourish, to borrow Sam Harris's terms10. Given these facts, there are certain things we ought to do to achieve those goals--such as cooperating with each other, creating social and legal institutions that regulate our interactions and create trust with strangers, obeying certain rules and laws, etc. These can be objective descriptions of the world: if we all decide to cheat and steal and kill each other, we will all have objectively less well-being than if we live together peaceably. (Consider: the maximally beneficial solution to a Prisoner's Dilemma is to cooperate). Why ought I not steal? Because I desire to live in a functional, friendly, and cooperative society rather than in a disjoint, terrorized, and broken society--and my not stealing is part of that.
IV. Objection 1: But, the theist may ask, why ought someone desire well-being of this sort? To that, you may answer: why ought someone desire health? Should we be afraid that without God, no one will take medicine prescribed by doctors because there is no objective command to be healthy? It's a silly question. We all want to be healthy. We all also want to live well and flourish as social animals (except for those with certain disorders, who have serious things wrong in their brain and are thus are not particularly relevant). Given that we desire this state, there are objective ways to achieve the goal and ways to get further away from this goal. If I see a tiger and have the goal of not being eaten, I ought to run away. If I am a social animal and have the goal of well-being as such, I ought to obey certain moral dictates.
Objection 2: "Not everyone wants well-being and flourishing! Religious extremists don't care about that stuff, for instance--they care about God's morality for it's own sake!" Answer: Of course they care about well-being. They just think they achieve the highest possible well-being by following certain dictates, i.e. not eating pork, blowing up infidels, disliking homosexuals. Imagine a religion that claimed the following revelation: "God wants you to do XYZ because it is Morally Right. But, if you do it, He will punish you with everlasting excruciating torment and distance from Him. If you violate these laws--which are still God's moral truths!--He will reward you with grace and closeness to Him and all goodness. Don't ask why--no one can understand God's logic!" How many people would follow the dictates of this religion?
V. In short:
1) We are wired to be social, cooperative creatures; we feel pain when we are socially excluded and when relevant others are in pain, and we feel pleasure when included or when cooperating successfully. Our physical and psychological well-being depends on successful social life.
2) Given that this is part of overall well-being we desire, just as we desire health, there are certain things we ought to do to achieve it and certain things we ought not do. The society in which women are mutilated at birth and free-thinkers are killed will objectively have less well-being than a free society, and we ought to move towards the latter.
3) We need no further metaphysical basis for morality; our everyday moral dilemmas are constraint satisfaction problems as we navigate solutions to our basic social needs.
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1 I came to many of the general conclusions here on my own, but was also much influenced by Patricia Churchland's BrainTrust and Sam Harris's The Moral Landscape. I highly recommend both to anyone interested in morality, science, and religion.
2 BrainTrust.
3 Rilling, J. (2011). The social brain in interactive games. In: Todorov, A. Fiske, S, Prentice D., eds. Social Neuroscience: Toward Understanding the Underpinnings of the Social Mind. Oxford Press.
6 Eisenberger, N. I. (2007). Using neuroimaging techniques to explore the relationship between social status and health. Social Cognitive and Affective Neuroscience, 2, 159-160.
7 Hamlin, J.K., et al. (2007.) Social evaluation by preverbal infants. Nature, 450:22.
8 Singer, T. et al. Empathy for pain involves the affective but not sensory components of pain. Science 303, 1157–1162 (2004).
9 Ochsner, K., et al (2008). Your pain or mine? Common and distinct neural systems supporting the perception of pain in self and others. Social, Cognitive, and Affective Neuroscience 3, 144-160
