Quantum Free Will -- Redux
I'll fix this up later... but for now here it is...
Introduction
For the last few centuries, those
wishing to deny the existence of genuine free will have looked to the
deterministic nature of the natural sciences, especially physics, to support
their claims. These “Determinists” have
found ample and convincing evidence for their claims in classical physics.
However, with the relatively recent advent of quantum physics, in the early
1920’s, a reassessing of the support provided to the Determinists’ position has
begun to occur. The orthodox
interpretation of Quantum Mechanics seems to provide a fruitful place to
undermine the Determinists’ supposition that physics, as a model of the world,
prohibits genuine free will. The purpose
of this paper is to provide background in the Free Will-Determinism Debate and
support genuine free will using the orthodox interpretation of quantum
mechanics.
Metaphysical Considerations
There are various metaphysical
considerations to be dealt with in Free Will-Determinism Debate.
define the metaphysical terms I will be using, then proceed to a brief analysis
of common views held in light of these definitions.
Definitions:
Freedom
“Freedom is the
power, rooted in reason and will, to act or not to act, to do this or that, and
so to perform deliberate actions on one's own responsibility.” (CCC 1731)
“Genuine” Free will
Genuine Free will
is the ability to control one’s actions via a choice that is determined as a
free agent. "The proper act of free will is choice, for we say that we have
a free-will because we can take one thing while refusing another; and this is
to choose... two things occur in choice... we judge one thing to be preferred
to another... [and] the appetite should accept the judgment..." (
Free agent
initiate and control his own actions … ‘[a] Master over his own acts’” (CCC
1730) Being a master over one’s own acts
entails both the abilities of “unique” initiation and “primary” control.
actually exhibit both or either of the abilities in a given action to grant it
the status of a genuine Free Will expression, it is sufficient that the agent
abilities, is not under duress and the action is voluntary.
responsible for actions, though this does not necessarily equate to full
responsibility as “[i]mputability
and responsibility for an action can be diminished or even nullified by
ignorance, inadvertence, duress, fear, habit, inordinate attachments, and other
psychological or social factors.” (CCC 1735).
“Unique” initiation
is the ability
of the self to cause events that would otherwise not occur if left to the sole
influence of natural events.
“Primary” control
is the ability of
the self, and thus not solely natural stimuli or events,
behaviours, thoughts, choices, desires, etc.
(Causal) Determinism
“The world
is governed by (or is under the sway of) determinism if and
only if, given a specified way things are at a time t, the way things
go thereafter is fixed as a matter of natural law.”
(Hoefer)
Indeterminism
is the view that there
are some events that are not causally “fixed as a matter of natural law,”
namely free will choices.
Common Views:
Two Primary divisions exist in the
Free Will-Determinism Debate, Incompatibilism and Compatibilism under which individual
views are further divided.
Incompatibilism
All views classified beneath
Incompatibilism deny that free will and a deterministic world are compatible,
they believe one necessarily precludes the other.
“Hard” determinism
Hard determinism is an
incompatibilist view that holds that the world IS deterministic in nature and thus genuine free will can not exist.
over their actions that is not fixed from antecedent events which extend even
prior to their birth. Thus this view can
not recognise genuine “responsibility” as people have no real influence upon
their own actions.
Libertarianism
“The view that some human actions
are free and not causally determined” (Geirsson 1998, 487).
there is no causal determinacy for actions, which leads to the possibility of
deliberating over a decision, deciding, preparing to act and instead of acting
the way decided and deliberated, the person acts in a completely different
fashion than intended, desired, chosen, or willed.
Thomas
judgment” as part of what it means to choose.
And if one can not choose, one can not have genuine free will.
Compatibilism
Compatibilist views hold that free
will and causal determinism are compatible, though how they are compatible are
the defining parts of the individual views.
“Soft”
determinism
The view that determinism and
this view rejects genuine free will
and claims that free will should be thought of as relative to one’s
desires. Meaningful free will for the soft determinist is not the ability to
have chosen differently given the circumstances, but that it is the ability to
have chosen differently had the agent willed so (i.e., under a different
predisposition of beliefs and desires) (Geirsson 1998, 367 and Wikipedia).
the very act of self deliberation determines an act as free, if the
deliberation leads to an action that is intentional and not coerced by an
external or internal agent (e.g., brainwashing or disease) (Roberts).
predispositions are determined. The
views under the classification of soft determinism are not consistent with the
free agent being a person who can ultimately control his own actions, as the
person lacks what is required for “primary” control, namely the ability of the
self to uniquely initiate
predispositions. Thus
responsibility seems ultimately unable to be attributed to the person.
Self-determinism
Self-determinism is “the view that
an action is free when it is produced by a free will, and a will is free when
it is determined by an agent who is not causally determined to will in this
way.” (Geirsson 1998, 489) This view is indeterministic in that the decisions
of a self-determined agent are not fixed by a natural law, though it is
deterministic in that there is some non-natural law that may govern this, which
may be completely unique to the individual free agent, generic to all free
agents, or most likely a mixture of both (discussions of this deterministic law
are beyond the scope of this paper, as it seems the discussion would be heavily
laden with theological concepts). According
to Geirsson only events can truly be
causally determined, and a free agent is not an event but a special object
with unique attributes, which permits it to be viewed as compatibilist (Geirsson
1998, 369). This view seems to be most in keeping with the idea of genuine free
will. But let us now turn to the Quantum
frame work which might be in most keeping with genuine free will.
Orthodox Quantum Framework
The
interpretation is considered the orthodox view of Quantum Mechanics and is most
widely supported by physicists. Two of
its relevant features for the Free will-Determinism Debate are its view that
quantum mechanics is inherently indeterministic via the Uncertainty Principle
and through Observer Dependence.
Uncertainty Principle
Heisenberg’s Uncertainty Principle
is an indeterminacy at the very heart of the Orthodox Interpretation.
states: “The more precisely the position is determined, the less precisely the
momentum is known in this instant, and vice versa.” (AIP 1). This is commonly interpreted as being due
to the wave/particle duality of all objects, where the wave aspect represents a
probability of the particle’s actual location which does not exist until
observed (see Observer Dependence below).
In the same paper, Heisenberg says “[i]n the sharp formulation of the
law of causality—‘if we know the present exactly, we can calculate the future’-it
is not the conclusion that is wrong but the premise.” (AIP 2) This inherent
uncertainty is hostile to Determinism, leading to an indeterminism that
provides for some events that are not causally fixed according to natural laws,
though these events are quantum events, not free will choices.
Observer Dependence
Observer Dependence is a response
to the indeterminacy in the Measurement Problem. This indeterminacy is due to
the relationship between the moments before and at the time an observation of
the system is made. Prior to
observation, a system is considered to be following the deterministic
“Schrödinger” dynamic. Schrödinger used
wave equations to describe quantum systems as one that exists in a
superposition, where any and
represented. At the time of observation, the system is said to exhibit the
“collapse” dynamic, where only one
outcome is present. The indeterminacy
arises from the “discontinuous, random ‘jump’” from the Schrödinger to
the collapse dynamic. This indeterminacy
exists if the Schrödinger wave equation has a minute length or a length that
spans light years.
Heisenberg formulates his response
to the measurement problem with regard to observation. “I believe that the
existence of the classical "path" can be pregnantly formulated as
follows: The "path" comes into existence only when we observe it.” (AIP
2) The concept of “path” does not exist except when we observe it, without
measurement
“the unobserved object is a mixture
of both the wave and particle pictures until the experimenter chooses
what to observe in a given experiment”(AIP 2).
Observer dependence is this idea that without an observer, a quantum system
remains in a superposition of all the possible states that it could be in.
without an observer to say it is either red or it is blue, then the ball is
said to have a mixture of both properties (the superposition).
This proposition is best
exemplified by the double slit experiment, in which an observer can determine
the behaviour of a particle by the act of
observing. The setup of the
experiment is as such: a single photon emitting light source is separated from
a detector by a barrier with two parallel slits.
photon’s behaviour is displayed by the detector as an interference pattern,
thus the single photon is said to have existed in a superposition of all
possible states (of travel between emitter and detector).
photon’s behaviour is displayed by the detector as a point, thus the single
photon is said to have existed in only one particular state due to the
observation.
The Connection
Quantum
mechanics does not provide for a world of uncaused events, but instead says
that individual quantum events are caused through an indeterministic principle
that precludes one from fully anticipating which possible outcome would occur.
indeterministic principle is in some manner a randomness amongst possible
measurements. I propose to support the
idea that there is some other indeterministic principle, namely free will, that
governs or affects specific quantum events.
Just as the basic quantum indeterminacy principle of randomness is
limited in scope by the matter to which it is tied, namely specific quantum
events, free will is limited in scope by
the actual matter to which it is tied, namely the individual free agent.
events is limited to the body of the individual free agent.
indeterminacy is to predetermine which consequent quantum event will occur,
akin to loading the dice. To further
understand this view, let us turn to some objections.
Objections to this view
Two primary objections to this view
are based on the assumptions of randomness and a classical limit.
Randomness
Philosopher
David Chalmers argues that “[T]he theory [that quantum indeterminacy allows
free will] contradicts the quantum-mechanical postulate that these microscopic
‘decisions’ are entirely random..” (Barr 2003, 180).
being significant metaphysically to the Free Will-Determinism Debate derives
from the very nature of the collapse dynamic.
Chalmers argues that either the state which the collapse dynamic
actualises is completely random or we would be able to notice detectable
patterns. He continues by saying that it is completely random.
argues that so far as states (all physical states not just quantum) are not
random they are deterministic. And if something is random or deterministic,
then there can be no rational free will decision involved.
not be the case.
Response to Randomness
Physicist
Stephen Barr says this is an “unnecessarily restrictive” view of quantum
mechanics. He insists that “if quantum
theory says two outcomes are equally probable, that can be interpreted simply
as meaning that there is nothing in the physical situation itself that prefers
one outcome to the other” (Barr 2003, 180).
Thus denying one of Chalmers’ premises, in favour of trying to show that
we can notice detectable patterns. In
this regard we refer to the scope of the free will, which is the agent.
agents? It is a fact that we indeed do, free
agent behaviour shows detectable
patterns, and Barr argues that such patterns are neither so exact that they can
be defined in terms of a mechanical law nor so erratic that they are completely
random (Barr 2003, 180).
Classical Limit
The idea of a classical limit is
the point where the indeterminacy of quantum theory stops and the determinacy
of a classical system takes over. It is
said the brain is past the classical limit, and thus Barr’s counter-argument to
Randomness fails, as even if we detect such patterns, they can’t be attributed
to quantum indeterminacy. Schrödinger proposed the necessity of a classical
limit via reductio ad absurdum in his classic gedankenexperiment, the
“Schrödinger cat”. Schrödinger stated
his argument as such:
A cat is penned up in a steel
chamber, along with the following diabolical device (which must be secured
against direct interference by the cat): in a Geiger counter there is a tiny
bit of radioactive substance, so small, that perhaps in the course of one hour
one of the atoms decays, but also with equal probability, perhaps none; if it
happens, the counter tube discharges and through a relay releases a hammer
which shatters a small flask of hydrocyanic acid.
self for an hour, one would say the cat lives if meanwhile no atom has
decayed. The first atomic decay would
have poisoned it. (Davies 1987, 29)
The
orthodox Quantum view of the cat in this enclosed box is that it must exist in
the superposition of being both alive and
dead, until an observer opens the box.
It is only at this point and not prior that the cat snaps into one of
the two states, it is either definitely alive or definitely dead, but this
seems absurd! In fact, if you place a
new box around the observer, the cat remains in the superposition until another
observer observers the first, and this continues into an infinite regression of
observers needing observing for the system to collapse.
macro level the effects of quantum indeterminacy ends (though at what point is
uncertain), and many view the brain to be immune in a practical way at least
from such effects.
Response to Classical Limit
Physicist/Mathematician
Roger Penrose (who objects to genuine free will) and Neurophysiologist Sir John
Eccles posit locations where quantum effects would affect the brain’s
functions. Penrose suggests
“‘microtubules,’ in the ‘cytoskeletons’ of the brain’s neurons” while Eccles
alternatively suggests, the “presynaptic vesicular grid” (Barr 2003, 183).
Though other relevant structures might be so inconspicuous and small that they
may never be discovered, and if they are, they may never be recognised as
such. In fact, it is not even clear that
such specialised spots are needed for quantum effects to influence the brain as
the actual method behind how a free agent could act upon quantum states is as
of yet undeveloped (Barr 2003, 183).
These suggestions provide further opportunities for free will to respond
to challenges against it.
Conclusion
The Orthodox Interpretation
of Quantum Mechanics supports genuine free will against its challengers,
specifically those that claim that world is deterministic and has no room for genuine
free will (determinisms) and against libertarianism’s permission of uncaused
events. All of which lead to worlds that
do not seem to be our own. The Orthodox
interpretation of Quantum Mechanics provides the small amount of indeterminacy
that is a great doorway held open for the possibility of free will.
posted by sirhair @ 8:27 PM
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