杏吧原创

IT IS common to feel uncomfortable when reading about new neuroscience techniques that seem to encroach on the sacrosanct realm of our hidden inner lives. And it is understandable to feel even more uncomfortable about the notion that our actions are dictated by processes in our brains, calling into question a place for moral responsibility. This discomfort pervades Eliezer Sternberg鈥檚 new book.

In My Brain Made Me Do It, Sternberg dips into philosophy, psychology and neuroscience research as he considers the various evidence that suggests we lack free will and thus a foundation for moral responsibility. Strange cases from psychology and neuroscience pose problems for a naive view of human agency. What if your hand started grabbing things of its own accord? Or if you were compelled to use every tool you found in front of you?

Keep some grains of salt handy as you are reading. The tone Sternberg takes to the possibility of widespread acceptance of neurobiological determinism is of the sky-is-falling variety. With over 40,000 practising neuroscientists, it isn鈥檛 hard to find juicy quotes dismissing the existence of free will, but it is inaccurate to characterise this as the general attitude of the field.

Sternberg addresses two related problems throughout the book. The first concerns the wide range of influences on our actions that we are unaware of at any given moment. If an action I take is triggered by unconscious sensory input, am I employing free will?

The second, known as the 鈥渃ausal exclusion problem鈥� in philosophy, is the one that really disturbs Sternberg. You, in the grand sense of 鈥測ou鈥� 鈥� your thoughts, emotions, volition and moral reasoning 鈥� depend on neuronal processing in your brain. If the firings of any neuron are enough to cause the next neuron to fire, your brain runs all on its own. There is no extra place in which you, as a higher-level, conscious being, can direct proceedings and assert free will. This clockwork determinism undermines any causal role we could have in our own actions 鈥� and, by implication, our responsibility for those actions.

鈥淭here is no extra place in your brain from which you can direct proceedings and assert free will鈥�

So what is Sternberg鈥檚 answer to the problem of free will? Emergence. This concept can be roughly summed up as 鈥渢he whole is more than the sum of the parts鈥�. Just as temperature emerges from a collection of molecules even though it does not exist at the level of individual molecules, free will, Sternberg argues, emerges from otherwise deterministic processes at the level of neurons.

Philosophers and scientists have been debating the merits of emergence in solving the free will problem since the 1920s. Rather than providing an account of exactly how free will could emerge from deterministic processes, Sternberg offers an analogy with the theory of continental drift. When it was first proposed, scientists dismissed it because it lacked a mechanism to account for how such massive objects could move over huge distances. Sternberg鈥檚 moral is that even though we don鈥檛 know how free will emerges, we will some day, so we shouldn鈥檛 throw moral responsibility out the window just yet.

Unfortunately, Sternberg misses his own point, and falls prey to the very line of thinking that he criticises. He offers 鈥渞eflective introspection鈥� as an alternative for addressing moral problems instead of what he calls the algorithmic approach, in which rules are computed to yield firm answers in decision-making situations.

But at the end of the day, whether we reason with rules or by transcending rules, we still can鈥檛 escape the fact that we reason using our brains. The problem comes in thinking that we are somehow sufficiently separate from our brains that those brains can tell us what to do or vice versa. Your brain, for better or for worse, is just the mechanism for being you.