Apologies for not posting anything recently. I have something in the works at BigThink and a few more in the pipeline but it has been hard finding the time to blog recently. I hope to be back to it in a couple of weeks.
The question of “where morals come from” has exercised philosophers, theologians and many others for millennia. It has lately, like many other questions previously addressed only through armchair rumination, become addressable empirically, through the combined approaches of modern neuroscience, genetics, psychology, anthropology and many other disciplines. From these approaches a naturalistic framework is emerging to explain the biological origins of moral behaviour. From this perspective, morality is neither objective nor transcendent – it is the pragmatic and culture-dependent expression of a set of neural systems that have evolved to allow our navigation of complex human social systems.
“Braintrust”, by Patricia S. Churchland, surveys the findings from a range of disciplines to illustrate this framework. The main thesis of the book is grounded in the approach of evolutionary psychology …
we’ve been thinking about the genetics of intelligence from completely the
wrong angle? Intelligence (as
indexed by IQ or the general intelligence factor “g”) is clearly highly heritable in humans – people who are more genetically
similar are also more similar in this factor. (Genetic variance has been estimated as explaining ~75% of variance in g,
depending on age and other factors).
There must therefore be genetic variants in the population that affect
intelligence – so far, so good.
But the search for such variants has, at its heart, an implicit
assumption: that these variants affect intelligence in a fairly specific way – that
they will occur in genes “for intelligence”. An implication of that phrase is that mutations in those genes were positively
selected for at some stage in humanity’s descent from our common ancestor with
apes, on the basis of conferring
increased intelligence. This
seems a fairly reasonable leap to make – such genes must exist and, if variation
Why did the axon cross the midline? That
seems like a simple enough biological problem to solve. In the developing
nervous system, especially in the anatomically simple spinal cord, some nerve
cells send a slender nerve fibre (called an axon) across the midline of the
nervous system to connect to cells on the other side. The projections of other
neurons are restricted to the same side as their own cell bodies. The
connections between the two sides are crucial in coordinating movement of the
two sides of the body. But, more importantly for this discussion, this system
is simple enough to be genetically tractable – at least it seems so. When I arrived as a graduate student in the
lab of Corey Goodman at the University of California at Berkeley, his group had
just carried out a genetic screen in fruit flies to try and understand how this
developmental decision was controlled. Flies have an equivalent of a spinal
cord, called the ventral nerve cord, and Corey and his colleagues had spent