Physicist tells people to stop saying they have free will
January 13, 2016 Posted by vjtorley under Intelligent Design
Over
at her BackReAction blog, Dr. Sabine Hossenfelder, a theoretical
physicist based at the Frankfurt Institute for Advanced Studies in
Frankfurt, Germany, has written an article titled, Free will is dead,
let’s bury it. However, her arguments against free will are both
scientifically unsound and philosophically dated. She writes:
There
are only two types of fundamental laws that appear in contemporary
theories. One type is deterministic, which means that the past entirely
predicts the future. There is no free will in such a fundamental law
because there is no freedom. The other type of law we know appears in
quantum mechanics and has an indeterministic component which is random.
This randomness cannot be influenced by anything, and in particular it
cannot be influenced by you, whatever you think “you” are. There is no
free will in such a fundamental law because there is no “will” – there
is just some randomness sprinkled over the determinism.
In neither case do you have free will in any meaningful way.
These
are the only two options, and all other elaborations on the matter are
just verbose distractions. It doesn’t matter if you start talking about
chaos (which is deterministic), top-down causation (which doesn’t
exist), or insist that we don’t know how consciousness really works
(true but irrelevant). It doesn’t change a thing about this very basic
observation: there isn’t any known law of nature that lets you
meaningfully speak of “free will”.
If
you don’t want to believe that, I challenge you to write down any
equation for any system that allows for something one could reasonably
call free will…
The
only known example for a law that is neither deterministic nor random
comes from myself. But it’s a baroque construct meant as proof in
principle, not a realistic model that I would know how to combine with
the four fundamental interactions.
First
of all, let’s get the bad science out of the way. Dr. Hossenfelder
insists that top-down causation “doesn’t exist.” She should try telling
that to George Ellis, an eminent cosmologist at the University of Cape
Town, whose scientific work is described by Adam Frank in an article
titled, How Does The World Work: Top-Down or Bottom-Up?, over at NPR’s
13.7: Cosmos And Culture blog:
In
an essay for the physics website FQXi, Ellis argues for top-down
causation. If he’s right, then much of our thinking about what matters
would have to be revised.
To
get an handle on how top-down causation works, Ellis focuses on what’s
in front of all us so much of the time: the computer. Computers are
structured systems. They are built as a hierarchy of layers, extending
from the wires in the transistors all the way up to the fully assembled
machine, gleaming metal case and all.
Because
of this layering, what happens at the uppermost levels — like you
hitting the escape key — flows downward. This action determines the
behavior of the lowest levels — like the flow of electrons through the
wires — in ways that simply could not be predicted by just knowing the
laws of electrons…
But the hardware, of course, is just one piece of the puzzle. This is where things get interesting. As Ellis explains:
Hardware
is only causally effective because of the software which animates it:
by itself hardware can do nothing. Both hardware and software are
hierarchically structured with the higher level logic driving the lower
level events.
In
other words, it’s software at the top level of structure that
determines how the electrons at the bottom level flow. Hitting escape
while running Word moves the electrons in the wires in different ways
than hitting escape does when running Photoshop. This is causation
flowing from top to bottom…
Ellis
is arguing for a kind of emergentism whereby new entities and new rules
emerge with new levels of structure in the universe (an argument also
made by Stuart Kaufmann here at 13.7). But Ellis is going further. He is
arguing that the top is always exerting an influence on the bottom.
Ellis
concludes his FQXI esssay, Recognising Top-Down Causation, with a bold
hypothesis, and he puts forward some concrete research proposals which
he believes will fundamentally transform the nature of science (bold
emphases mine – VJT):
Hypothesis:
bottom up emergence by itself is strictly limited in terms of the
complexity it can give rise to. Emergence of genuine complexity is
characterised by a reversal of information flow from bottom up to top
down [27].
The
degree of complexity that can arise by bottom-up causation alone is
strictly limited. Sand piles, the game of life, bird flocks, or any
dynamics governed by a local rule [28] do not compare in complexity with
a single cell or an animal body. The same is true in physics:
spontaneously broken symmetry is powerful [16], but not as powerful as
symmetry breaking that is guided top-down to create ordered structures
(such as brains and computers). Some kind of coordination of effects is
needed for such complexity to emerge.
The
assumption that causation is bottom up only is wrong in biology, in
computers, and even in many cases in physics, for example state vector
preparation, where top-down constraints allow non-unitary behaviour at
the lower levels. It may well play a key role in the quantum measurement
problem (the dual of state vector preparation) [5]. One can bear in
mind here that wherever equivalence classes of entities play a key role,
such as in Crutchfield’s computational mechanics [29], this is an
indication that top-down causation is at play.
There are some great discussions of the nature of emergent phenomena in physics [17,1,12,30], but
none of them specifically mention the issue of top down causation. This paper proposes that
recognising
this feature will make it easier to comprehend the physical effects
underlying emergence of genuine complexity, and may lead to useful new
developments, particularly to do with the foundational nature of quantum
theory. It is a key missing element in current physics.
Having
disposed of Dr. Hossenfelder’s claim that top-down causation doesn’t
exist, I’d now like to examine her philosophical argument. Briefly, the
argument she puts forward is a variant of what Bob Doyle describes as
The Standard Argument against Free Will, at his Information Philosopher
Website:
First, if determinism is the case, the will is not free. We call this the Determinism Objection.
Second,
if indeterminism and real chance exist, our will would not be in our
control, we could not be responsible for random actions. We call this
the Randomness Objection.
Together,
these objections can be combined in the Responsibility Objection,
namely that no Free Will model has yet provided us an intelligible
account of the agent control needed for moral responsibility.
Both
parts are logically and practically flawed, partly from abuse of
language that led some 20th-century philosophers to call free will a
“pseudo-problem,” and partly from claims to knowledge that are based on
faulty evidence.
So
why does Doyle think the Standard Argument Against Free Will is flawed?
First, Doyle argues that determinism is empirically false: quantum
physics introduces a significant degree of indeterminism into the world,
even at the macro level. Second, Doyle maintains that chance would
undercut freedom only if it were a cause of our actions, but in his
preferred two-stage Cogito model, it’s not: chance serves to dish up a
random array of possibilities, and then something called “MacroMind”
takes over, and makes a decision, based on the individual’s past history
of preferences. However, I don’t propose to discuss Doyle’s Cogito
model further here, because Doyle himself rejects the strong libertarian
view (which I support), that “a decision is directly free only if,
until it is made, the agent is able to do other than make that decision,
where this is taken to require that, until the action occurs, there is a
chance that it will not occur.” Indeed, Doyle explicitly acknowledges
that in his Cogito model, during the split-second before a choice is
made, “the decision could be reliably (though not perfectly) predicted
by a super-psychiatrist who knew everything about the agent and was
aware of all the alternative possibilities.” To my mind, that’s a
Pickwickian account of freedom.
For
her part, Dr. Hossenfelder vehemently disagrees with Doyle’s contention
that quantum physics entails indeterminism: she points out that
superdeterminism (the hypothesis that the quantum measurements that
experimenters choose to make are themselves predetermined by the laws of
physics) is an equally consistent possibility – and, I might add, one
that was acknowledged by John Bell himself: see The Ghost in the Atom: A
Discussion of the Mysteries of Quantum Physics, by Paul C. W. Davies
and Julian R. Brown, 1986/1993, pp. 45-47). For my part, I think
physicist Anton Zeilinger identified the flaw in superdeterminism when
he perceptively commented:
[W]e
always implicitly assume the freedom of the experimentalist… This
fundamental assumption is essential to doing science. If this were not
true, then, I suggest, it would make no sense at all to ask nature
questions in an experiment, since then nature could determine what our
questions are, and that could guide our questions such that we arrive at
a false picture of nature. (Dance of the Photons, Farrar, Straus and
Giroux, New York, 2010, p. 266.)
Additionally,
I should point out that even on a classical, Newtonian worldview,
determinism does not follow. Newtonian mechanics is popularly believed
to imply determinism, but this belief was exploded over two decades ago
by John Earman (A Primer on Determinism, 1986, Dordrecht: Reidel,
chapter III). In 2006, Dr. John Norton put forward a simple illustration
which is designed to show that violations of determinism can arise very
easily in a system governed by Newtonian physics (The Dome: An
Unexpectedly Simple Failure of Determinism. 2006 Philosophy of Science
Association 20th Biennial Meeting (Vancouver), PSA 2006 Symposia.) In
Norton’s example, a mass sits on a dome in a gravitational field. After
remaining unchanged for an arbitrary time, it spontaneously moves in an
arbitrary direction. The mass’s indeterministic motion is clearly
compatible with Newtonian mechanics. Norton describes his example as an
exceptional case of indeterminism arising in a Newtonian system with a
finite number of degrees of freedom. (On the other hand, indeterminism
is generic for Newtonian systems with infinitely many degrees of
freedom.)
Sometimes
the Principle of Least Action is said to imply determinism. But since
the wording of the principle shows that it only applies to systems in
which total mechanical energy (kinetic energy plus potential energy) is
conserved, and as it deals with the trajectory of particles in motion, I
fail to see how it would apply to collisions between particles, in
which mechanical energy is not necessarily conserved. At best, it seems
that the universe is fully deterministic only if particles behave like
perfectly elastic billiard balls – which is only true in an artificially
simplified version of the cosmos.
Finally,
I should like to add that in my own top-down model of free will (as
with Doyle’s), chance does not figure as a cause of our choices. In my
model, it serves as the matrix upon which non-random, but undetermined,
free choices are imposed, via a form of top-down causation. Here’s how I
described it in a 2012 post titled, Is free will dead?:
…[I]t
is easy to show that a non-deterministic system may be subject to
specific constraints, while still remaining random. These constraints
may be imposed externally, or alternatively, they may be imposed from
above, as in top-down causation. To see how this might work, suppose
that my brain performs the high-level act of making a choice, and that
this act imposes a constraint on the quantum micro-states of tiny
particles in my brain. This doesn’t violate quantum randomness, because a
selection can be non-random at the macro level, but random at the micro
level. The following two rows of digits will serve to illustrate my
point.
1 0 0 0 1 1 1 1 0 0 0 1 0 1 0 0 1 1
0 0 1 0 0 0 0 1 1 0 1 1 0 1 1 1 0 1
The
above two rows of digits were created by a random number generator. The
digits in some of these columns add up to 0; some add up to 1; and some
add up to 2.
Now
suppose that I impose the non-random macro requirement: keep the
columns whose sum equals 1, and discard the rest. I now have:
1 0 1 1 1 0 0 0 0 0 1
0 1 0 0 0 1 1 0 1 1 0
Each
row is still random (at the micro level), but I have now imposed a
non-random macro-level constraint on the system as a whole (at the macro
level). That, I would suggest, what happens when I make a choice.
Top-down causation and free will
What
I am proposing, in brief, is that top-down (macro–>micro)
causation is real and fundamental (i.e. irreducible to lower-level
acts). For if causation is always bottom-up (micro–>macro) and
never top-down, or alternatively, if top-down causation is real, but
only happens because it has already been determined by some preceding
occurrence of bottom-up causation, then our actions are simply the
product of our body chemistry – in which case they are not free, since
they are determined by external circumstances which lie beyond our
control. But if top-down causation is real and fundamental, then a
person’s free choices, which are macroscopic events that occur in the
brain at the highest level, can constrain events in the brain occurring
at a lower, sub-microscopic level, and these constraints then can give
rise to neuro-muscular movements, which occur in accordance with that
person’s will. (For instance, in the case I discussed above, relating to
rows of ones and zeroes, the requirement that the columns must add up
to 1 might result in to the neuro-muscular act of raising my left arm,
while the requirement that they add up to 2 might result in the act of
raising my right arm.)
As
far as I’m aware, there’s no law of physics which rules out the idea
that patterns of random events (such as radioactive decay events) might
turn out to be non-random at the macro level, while remaining random at
the micro- or individual level. Of course, as far ass we know,
radioactive decay events are random at the macro level, but the same
might not be true of random neuronal firings in the brain: perhaps here,
scientists might find non-random large-scale patterns co-existing with
randomness at the micro- level.
Putting
it another way: even if laboratory experiments repeatedly failed to
detect patterns in a random sequence of events over the course of time,
this would not establish that these events are randomly distrubuted
across space as well. Hence large-scale spatial patterns are perfectly
compatible with temporal randomness, at the local level.
In
her blog post, Dr. Hossenfelder challenges her readers to “write down
any equation for any system that allows for something one could
reasonably call free will.” It’s a challenge she has already met, with
her free will function in part 3 of her ARXIV essay, in which “each
decision comes down to choosing one from ten alternatives described by
the digits 0 to 9”:
Here is an example: Consider an algorithm that computes some transcendental
number, τ, unknown to you. Denote with τn the n-th digit of the number after the
decimal point. This creates an infinitely long string of digits. Let tN be a time very
far to the future, and let F be the function that returns τN−i for the choice the agent
makes at time ti.
This has the following consequence: The time evolution of the agent’s state is
now no longer random. It is determined by F, but not (forward) deterministic: No
matter how long you record the agent’s choices, you will never be able to predict,
not even in principle, what the next choice will be…
Dr.
Hossenfelder’s example is mathematically elegant, but it’s really not
necessary, in order to salvage the idea of free will. All that is needed
is to show that the the idea of top-down causation which is irreducible
to preceding instances of bottom-up causation remains a valid one in
physics, and that this, coupled with the suggestion that the mind can
make non-random global selections from random sequences of events
without destroying their local randomness, is enough to render the ideas
of agent-causation and strong libertarian free will scientifically
tenable. How the mind makes these selections and influences processes
within the brain is a question for another day (for a discussion, see
here and here). All that I have been concerned to show here is that no
laws of physics are broken, even if one adopts a very robust version of
libertarian free-will.
