This article was originally posted on April 21, 2011.

Where does our sense of right and wrong come from? Great philosophers like Aristotle and John Stuart Mill? The divine? What about biology? Morality has long been considered the exclusive realm of philosophy and theology – off limits to science.  

One of main reasons for this line in the sand on morality is the “Is-Ought problem” put forward by Scottish philosopher David Hume. Put simply, no combination of statements about what “is” the case could ever allow one to deduce what “ought” to be.

Science can tell us what “is” and philosophy and religion tell us what “ought” to be. Morality is thought to be questions of “ought” as in what is the right and wrong thing to do. But a key question is where morality comes from and why it develops. That is an “is” question that science is beginning to tackle. 

This was the subject of a special report in an October issue of New Scientist. In the introductory piece, Fiery Cushman, equates the progression of morality with a lucid dream: first you experience it as reality, then as a product of your mind and then you gain control. While at first we thought of morality as divine command or in the Platonic sense of absolute right and wrong, science is now telling us morality may be a product of our brains.

 "… new research is offering an alternative, explaining moral attitudes in the context of evolution, culture and the neural architecture of our brains. This apparent reduction of morality to a scientific specimen can seem threatening, but it needn’t. Rather, by unmasking our minds as the authors of morality, we may be better able to bend its narrative arc towards a happy end.”

For example, one of the great mysteries of evolution is altruism. Why would one creature help another at its own expense? According to natural selection, the fittest pass down their genes to the next generation and so every creature has an incentive to survive and reproduce. But how can we explain the self-sacrifice that exists in the natural world? The answer is biology.

Harvard biologist Edward O. Wilson is shaking up the scientific community with his theory on the roots of altruistic behaviour. He argues that

“Under certain circumstances, groups of cooperators can out-compete groups of non-cooperators, thereby ensuring that their genes — including the ones that predispose them to cooperation — are handed down to future generations. This so-called group selection … is what forms the evolutionary basis for a variety of advanced social behaviors linked to altruism, teamwork, and tribalism.”

Science can’t give us absolute answers about what is morally right or wrong (some, like Sam Harris, think it can – watch his TED Talk here), but it can help explain where our sense of right and wrong came from and how it developed.

One of tonight’s guests, Patricia Churchland, aims to do just that in her new book “Braintrust: What Neuroscience Can Tell Us About Morality.” Her hypothesis is that morality originates in the neurobiology of attachment and bonding. What does that mean? Well, our brains contain neural circuitry responsible for basic survival: It regulates our temperature, carbon dioxide and glucose levels, for example. Our brain likes to keep our body in homeostasis – in balance – and does so by triggering pain, hunger, thirst and fear as well as the pleasures of food, water, sex and safety.

As mammals’ brains evolved, the neural network keeping our body in homeostasis expanded its scope to include our helpless offspring and, in some species, expanded to include kin and other members of the group. In other words, our personal circle of survival expanded. Churchland, writes, “Attachment, underwritten by the painfulness of separation and the pleasure of company and managed by intricate neural circuitry and neurochemicals, is the neural platform for morality.”

But the mammalian brain is also special because of the neocortex – the six layer mantle covering the brain’s hemispheres – which is responsible for an enhanced capacity to predict others’ behaviour and enables abstract learning and problem solving as well as impulse control and social skills. It is these skills that helped humans develop trade practices, criminal justice systems and religions – all of these cultural institutions allowed to develop relationships of trust among non-kin.

Morality, for Churchland, then is “a natural phenomenon – constrained by the forces of natural selection, rooted in neurobiology, shaped by the local ecology and modified by cultural developments.”

It’s a fascinating hypothesis with huge implications, if proven. What role is there for religion if one its core purposes is now a matter of biology? What changes would we need to make to our criminal justice system? Does this mean that certain moral questions have universal answers? How do we resolve more complex moral quandaries, such as euthanasia?