A Quantum impact on the Free will-Determinism Debate: Redux

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. To clarify the scope of this paper, I will first 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..." (Summa Theologica I, 83,3 in Kreeft 1990, 299)

Free agent

is one who has free will or “[a] person who can 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. It is not necessary for a free agent to 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 has and can utilise these abilities, is not under duress and the action is voluntary. From this “free agency” one can be deemed 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, to dispose or predispose oneself to certain 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. This is as people have no control or choice 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). This view falls under indeterminism in that 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. This is contrary to St. Thomas’ idea that “the appetite should accept the 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 meaningful free will are compatible, 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). An alternate view of soft determinism is that 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). Soft determinist views hold that 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 Copenhagen 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. In the Uncertainty Paper of 1927, Heisenberg 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 all possible measurement outcomes are 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. That is, if a ball can be red or blue, then 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. If the observer chooses TO NOT observe which slit the single photon goes through, then the 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). If the observer chooses TO observe which slit the single photon goes through, then the 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. In general it is understood that the 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. So the effects of free will upon quantum events is limited to the body of the individual free agent. The effects of free will upon quantum 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). This first argument against quantum effects 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. And randomness does not lead to freewill, he 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. So he concludes that either way free will can 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. Do we notice detectable patterns in free 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. If one has left this entire system to its 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. From this it is generally viewed that at some 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.