The ideas of free will, causality, and determinism, often factor into discussions about religion, morality, society, consciousness, or life in general. The first and last of these ideas seem at odds; if the world is strictly determined, there can be no free will.
But we are confronted with the appearance of free will — choices we make appear to affect the future. Even choosing not to make choices seems to affect our future. If reality is just a ride on fixed rails, then all that choosing must be a trick our brains play.
These questions are central to lives, but answers have remained elusive, in part from differing views of what the key ideas even mean.
Sometimes a precise definition of terminology helps make things more clear. Sometimes it doesn’t, but at least it’s a good place to start.
(“Doe, a deer,…”)
Free will is generally defined as the ability to make a choice that seems arbitrary in terms of past information.
It’s the idea that, if we rewind time to a given choice, a different choice was possible at that point, even though the past would be the same for both choices.
When I look in my pantry to decide which kind of soup to have, and I pick minestrone, could I have picked clam chowder instead? Or does the physics of reality insist that, at that moment, I must choose minestrone?
[It gets weird: If free will truly doesn’t exist, I was always going to write this post and ask these questions. (And you were always going to read it.) Every opinion we have on this, any actions we take based on those opinions, are predetermined.]
Determinism generally means we can accurately predict future states of the system given its current state.
Alternately, it means the current state allows us to deduce past states — which includes an implication there is only one possible past. (The first view implies there is only one possible future.)
Essentially determinism sees a system as a clockwork machine that can be wound forward or backward to any point with the same result. Wind to any given point and we always get the same system state.
That is, assuming the determined system is bi-directional — that need not be the case. A system can be determined in only one direction.
For instance, the current state might allow predicting future states, but past ones might be unknowable due to information loss. If the hands on an electric clock say it’s twenty after four, when was the clock plugged in? How many times have the hands gone around?
Or perhaps the current state implies a specific past, but there is some randomness to future states. This, in fact, seems to be how things are. Or at least how they appear.
I think we tend to think of determinism as applying to future states. But a fully reductive machine-like view of reality implies bi-directional determinism.
Causality seems a questionable concept to some philosophers. For me it’s nothing more, or less, than the laws of physics.
These laws provide an explanation for why A “causes” B.
Essentially it’s a case of local interactions. Light cones are significant. That the speed of causality, the speed of light, and the max allowed speed, are all the same thing is a central axiom of reality.
That said, there is a philosophical point as to whether physical laws are just observations of patterns with no necessary underlying causal connection or whether those observations do reflect a lawful causal universe.
Given the consistency of our observations, the latter seems a reasonable bet. We appear to exist in a physical reality governed by physical laws.
Those laws say why A causes B — because gravity, or mass, or magnetism, or charge, or frequency, or whatever.
The basic laws of physics are seen as bidirectional in time, which implies causality is bidirectional.
For some this suggests an issue with causality. If A causes B, but B also causes A, isn’t that a contradiction?
It isn’t, because in any given situation, one always causes the other. That a causal link is potentially bidirectional doesn’t mean both happen at the same time.
So causality, as a set of physical laws, is bidirectional — the extra ingredient is time, which (I believe) is fundamental, and which runs in only one direction. (In my view, causality and entropy are, demonstrations of time’s arrow; they do not create it.)
The laws of physics, plus time, result in (one-way) causality as we perceive it.
[I stress this is just my view: Time is fundamental. We live in an evolving universe. The past “happened” and is fixed; the future is undetermined; “now” divides them. I like the metaphor of the loom. We weave a fixed past from threads available to us.]
Determinism is about how predictable causality is.
If the result of a causal interaction has a single outcome which can be predicted, then that interaction is determined. If all interactions are determined, then the future is determined.
In reverse, if all outcomes have only one possible history, then the past is determined.
I don’t believe either of those are strictly true.
Note that systems can be determined (or not) at different levels. A key question involves determinism at different scales.
Also note there are things — chaos, for instance — that effectively interfere with our ability to predict a determined system, except in the short term. Another example is how the way things degrade over time interferes with our ability to determine the past.
At reality’s lowest level, the Schrödinger equation, which describes the evolution of a quantum system, is fully determined.
My understanding is it is bidirectional — it describes the system’s dynamics forwards or backwards. The implication is there is only one possible past given the present, which is why quantum information is never lost.
The wrinkle in all this involves actually “looking at” that evolving system (making a measurement). When we do that, the Schrödinger wave-function “collapses” to some random value among possible values the system could have.
Which is all she wrote for determinism at the quantum level.
If anything, the quantum world is noted for its randomness!
Physical law at higher levels are also determined, and there is no random wave-function collapse.
That would seem to make (for example) chemistry deterministic. On the large scale, I suspect it is, but I’m dubious about the fine scale.
To be strictly determined on the fine scale, a specific configuration of trillions of atoms must evolve in exactly the same way every time. There can never be a single atom out of step or out of place.
One problem here is there’s no way to accomplish this experimentally (or even accidentally). Due to Heisenberg, it is impossible to give one atom, let alone a huge group of them, a specific position and momentum.
So while chemistry has determined outcomes, you get so many ounces if you do this, that, and the other thing, I’m not sure the outcome is determined down to the atom.
[For one thing, new research has shown important quantum interactions between molecules of water. Those interactions affect its viscosity.]
At higher and higher levels, we’re dealing with larger and larger quantities, which seems to make strict determinism weaker and weaker.
Reality is definitely causal, but I think it is fuzzy enough that it’s not determined. Not in the strict physics sense.
I think the past is determined in a causal sense, but not in a one-history sense.
Given a current configuration, and physical laws, it’s possible to see how a preceding state evolved into the following state. But in some cases, multiple possible previous states might all lead to the same following state.
A common example is a glass of water. It might have been a glass of ice cubes, or it might have been a glass of hot water. Both pasts lead to the current state.
There are social and personal forms of determinism, but I think we are not so much like Pavlov’s dogs that we can’t overcome those if we try.
But I don’t think I live in a strictly determined world, a clock-like machine world that could potentially be wound forwards or backwards.
I think complex systems may not be determined, and since the brain is a very complex system, it may not be determined. Which puts free will back on the table where it at least feels like it belongs.
I can’t remember who I heard say it, but someone recently expressed something I’ve been saying for a while: chaotic systems in the brain may result in free will.
It would certainly explain why, despite millions of years of evolution, our brains seem to make decisions in an undetermined world.
Stay causally determined, my friends!