Originally Posted by Fourier
That's not my reading of the neurological literature. Libet's work was originally criticised and then became accepted more during the 1990s. Since the mid-2000s further studies have been done that have left the state of the whole area more complex and confusing with no clear conclusions.
As the boundaries of knowledge in neuroscience are pushed further out, it is entirely to be expected for the landscape of knowledge should grow more complex, like a blind man regaining his sight. When in the process of scientific discovery doesn't
that happen? I don't see how growing complexity can be used to refute the studies that have reproduced Libet's work.
There are valid criticisms of Libet and subsequent related research, their methodologies and how they drew conclusions, of course.
So lets ignore Libet for a moment and return to basic human reasoning involving a real life case-study.
We know that neurochemical and anatomical changes in the brain cause massive changes in our behaviour. Charles Whitman is a classic example
. Whitman led a normal, humdrum life -- until one day he killed 16 people including members of his own family, whom he loved. Whitman asked for his brain to be examined after his suicide, and eventually a panel of medical experts affirmed that Whitman's behaviour was due to a tumour disrupting neural processes in his amygdala, which is widely cited as a reason for his extraordinary, violent behaviour.
This is nothing new; for well over a century, the legal system has recognised how neurological disorders can cause a killer to be not guilty for their crime.
A person suffering with clinical depression who is prescribed the correct type and dosage of an SSRI/ SNRI will usually have their systems relieved, to the point where their personality may change altogether.
If I go out tonight and consume MDMA, I'll be more friendly and empathetic.
The materialistic/ deterministic concept of human behaviour is visible to all of us, every day. If you don't have enough glucose in your blood, you're likely to be lethargic and unable to focus. If you have elevated testosterone, you're more likely to get in a fight.
Knowing this, then even if Libet et al. had never conducted their research into brain activity and conscious decision-making, we should still be extremely skeptical about some invisible, quasi mystical 'driving force' within our brains (souls?), when we know that we are constantly doing strange things because of our biochemistry and neuroanatomy which, in retrospect, can cause us surprise or alarm that we behaved in those ways.
Humans having Free Will is just as in line with the evidence as the alternative. Human predictability is quite low in many circumstances.
No, it isn't. There is literally no scientific evidence for the existence of free will.
In fact, the trend in neuroscience over the past 100 years or so, has been to increasingly demonstrate biological reasons for human behaviour.
It is only in the past 70 years or so we've even known about ADHD, the biochemistry of depression, schizophrenia, and even epilepsy. 30 years ago we didn't even know about various personality disorders, now we know they have a genetic component, as does alcoholism. The march of biology is moving in a very clear direction, and it isn't favouring the omnipotent humunculus.
Subatomic systems' behaviour is not controlled by other physical facts. Thus what they do seems autonomous from other physical systems. This is not the same as the popular conception of randomness.
Why would quantum indeterminacy be relevant here? It shows unpredictability, for sure, but that's not necessarily at odds with biological determinism. The fact that we cannot predict (or understand) aspects of our brain doesn't cause us to resort to "Oh well it must be my mystical free will instead"
To return to the OP and the topic at hand, at the very least, developments in neuroscience and biology should cause people to question a lot of things about our species, but most relevantly for the purposes of this discussion, it raises serious doubts about a lot of the writing of Sartre and other existentialists, but especially Sartre.