Causality has confounded philosophers for centuries. Leibniz believed in the Principle of Sufficient Reason that everything must have a reason or cause. Bertrand Russell denied the law of causality, and argued that science should not seek causes.
Of course causality is central to science, and to how we personally make sense out of the world.
It is now commonplace for scientists to deny free will, particularly among popular exponents of atheism, evolution, and leftist politics. Philosopher Massimo Pigliucci rebuts Jerry Coyne and others, and John Horgan rebuts Francis Crick.
The leading experiments against free will are those by Benjamin Libet and John-Dylan Haynes. They show that certain brain processes take more time than is consciously realized, but they do not refute free will. See also contrary experiments.
The other main argument against free will is that a scientific worldview requires determinism. Eg, Jerry Coyne argues against contra-causal free will, and for biological determinism of behavior. Einstein hated quantum mechanics because it allowed for the possibility of free will.
A common belief is that the world must be either deterministic or random, but the word "random" is widely misunderstood. Mathematically, a random process is defined by the Kolmogorov axioms, and a random variable is a function on a measure-1 state space. That is, it is just a way of parameterizing outcomes based on some measurable set of samples. Whether or not this matches your intuition about random variables depends on your choice of Probability interpretation.
Wikipedia has difficulty defining what is random:
Randomness means different things in various fields. Commonly, it means lack of pattern or predictability in events.In mathematics, the digits of Pi (π) can be said to be random or not random, depending on the context. Likewise scientific observations may or may not be called random, depending on whether there is a good explanation. Leading evolutionists Richard Dawkins and S.J. Gould had big disputes over whether evolution was random.
The Oxford English Dictionary defines "random" as "Having no definite aim or purpose; not sent or guided in a particular direction; made, done, occurring, etc., without method or conscious choice; haphazard." This concept of randomness suggests a non-order or non-coherence in a sequence of symbols or steps, such that there is no intelligible pattern or combination.
There is no scientific test for whether the world is deterministic or random or something else. You can drop a ball repeatedly and watch it fall the same way, so that makes the experiment appear deterministic. You will also see small variations that appear random. You can also put a Geiger detector on some uranium, and hear intermittent clicks at seemingly random intervals. But the uranium nucleus may be a deterministic chaotic system of quarks. We can never know, as any attempt to observe those quarks will disturb them.
Likewise there can be no scientific test for free will. You would have to clone a man, replicate his memories and mental state, and see if he makes the same decisions. Such an experiment could never be done, and would not convince anyone even if it could be, as it is not clear how free will would be distinguished from randomness. Free will is a metaphysical issue, not a scientific one.
Even if you believe in determinism, it is still possible to believe in free will.
A debate between determinists Dan Dennett and Sam Harris was over statements like:
If determinism is true, the future is set — and this includes all our future states of mind and our subsequent behavior. And to the extent that the law of cause and effect is subject to indeterminism — quantum or otherwise — we can take no credit for what happens. There is no combination of these truths that seems compatible with the popular notion of free will.But that is exactly what quantum mechanics is -- a combination of those facts that is compatible with the popular notion of free will.
In biology, this dichotomy between determinism and randomness has been called the Causalist-Statisticalist Debate.
At the core of their confusion is a simple counterfactual:
Consider the case where I miss a very short putt and kick myself because I could have holed it. It is not that I should have holed it if I had tried: I did try, and missed. It is not that I should have holed it if conditions had been different: that might of course be so, but I am talking about conditions as they precisely were, and asserting that I could have holed it. There is the rub. [Austin’s example]The problem here is that they think that determinism is a philosophical necessity, and so they fail to grasp the meaning of a counterfactual.
In public surveys, people overwhelmingly reject this deterministic view:
Imagine a universe (Universe A) in which everything that happens is completely caused by whatever happened before it. This is true from the very beginning of the universe, so what happened in the beginning of the universe caused what happened next, and so on right up until the present. For example one day John decided to have French Fries at lunch. Like everything else, this decision was completely caused by what happened before it. So, if everything in this universe was exactly the same up until John made his decision, then it had to happen that John would decide to have French Fries.And so an atheist biologist writes:
To me, the data show that the most important task for scientists and philosophers is to teach people that we live in Universe A.That is a tough sell, as Universe A is contrary to common sense, experience, and our best scientific theories.
Steven Weinberg has argued that the laws of physics are causally complete, but also that we are blindly searching for the final theory that will solve the mysteries of the universe. A final theory would explain quark masses and cancel gravity infinities.
Einstein had an almost religious belief in causal determinism, and many others seem to believe that a scientific outlook requires such a view. On the other hand, a majority of physicists today assert (incorrectly) that quantum mechanics has somehow proved that nature is intrinsically random.
Quantum mechanics is peculiar in that it leaves the possibility of free will. It is the counterexample to the notion that a scientific theory must be causal and deterministic, or otherwise contrary to free will. If you tried to concoct a fundamental physical theory that could accommodate free will, it is hard to imagine a theory being better suited for free will.
Some interpretations of quantum mechanics are deterministic and some are not, as so, as Scott Aaronson explains, determinism is not a very meaningful concept in the context of quantum mechanics.
If you reject free will and the flow of time, and believe that everything is determined by God or the Big Bang, then counterfactuals make no sense. Most of time travel in fiction makes no sense either. The concept of counterfactuals depends on the possibility of alternate events, and on time moving forward into an uncertain future.
Regardless of brain research and the scientific underpinnings of free will, counterfactuals are essential to how human beings understand the progress of time and the causality of events.