Dr Robert Sapolsky was a guest on the Big Picture Science podcast on June 19, 2017. The full show is worth listening to, but I have put together a transcript of some of his key thoughts. As he makes clear, many people find it unnerving to accept that free will is essentially an illusion. If a man wanted to understand why humans behave the way they do, and why they have behaved in certain ways in the past, the place to start is biology, for nothing can be separated from it.
History, for example, plays the all important role of telling us how a certain leader might have behaved in the past, but it tells us nothing about why that organism acted in that way, and what drove the other members of his species to adopt him as their leader. To ignore biology is ignorance at best and stupidity at worst, for it remains the foundation upon which a holistic understanding of our world should be built
Everybody should study the biology of behaviour because tacitly we are all behavioural biologists. When we sit on a jury, we are being one because we are deciding something about the inevitability or the malleability of certain behaviours and its context dependency. If we are dealing with a loved one sunk in some psychiatric disorder, are they being clinically depressed because they have got screwy serotonin levels or are they indulging themselves? At every one of these junctures we are implicitly making decisions about how free or not we are as organisms in the context of the biology of our behaviour.
...My take which has taken me a long time to get to and I fully recognise often does not sit well with people: there's no agency. Agency is what we call the biological influences which have not been discovered yet.
At this stage there are all sort of aspects of human behaviour we can not explain, let alone predict. Absolutely without question, the biology we know does not explain even a large percentage of our behaviours because individual variability is enormous. Absolutely without question those leave gaping vacuums that beg for a sense of agency or a little homunculus sitting there doing free will at a control panel in our heads, but if one takes the larger view, all we keep doing is learning more and more and more about these subterranean biological forces that are shaping us. We know we have already gone enormous distances in accepting emotionally some of them...
More and more we are getting these biological threads that are influencing our behaviour in domains we never ever would have suspected and domains where we fill in rationalisation after the fact to try and make it seem volitional and agency-filled. (With) the accelerated pace of knowledge...all that's going to happen is the amount of space free will has is going to get more and more cramped and my personal opinion is it will eventually evaporate and it's just not there. Free will is the biology we don't understand yet.
Link to the referenced study (in the full interview) on how the judicial decisions of judges in Israel were influenced by how soon they were made after a lunch break: