Libertarianism is one of the main philosophical positions related to the problems of free will and determinism, which are part of the larger domain of metaphysics. In particular, libertarianism, which is an incompatibilist position, argues that free will is logically incompatible with a deterministic universe and that agents have free will, and that, therefore, determinism is false. Although compatibilism, the view that determinism and free will are in fact compatible, is the most popular position on free will amongst professional philosophers, metaphysical libertarianism is discussed, though not necessarily endorsed, by several philosophers, such as Peter van Inwagen, Robert Kane, Robert Nozick, Carl Ginet, Harry Frankfurt, E.J. Lowe, Alfred Mele, Roderick Chisholm, Daniel Dennett, and Galen Strawson.
Metaphysical libertarianism is one philosophical view point under that of incompatibilism. Libertarianism holds onto a concept of free will that requires the agent to be able to take more than one possible course of action under a given set of circumstances.
Accounts of libertarianism subdivide into non-physical theories and physical or naturalistic theories. Non-physical theories hold that the events in the brain that lead to the performance of actions do not have an entirely physical explanation, and consequently the world is not closed under physics. Such interactionist dualists believe that some non-physical mind, will, or soul overrides physical causality.
Explanations of libertarianism that do not involve dispensing with physicalism require physical indeterminism, such as probabilistic subatomic particle behavior – a theory unknown to many of the early writers on free will. Physical determinism, under the assumption of physicalism, implies there is only one possible future and is therefore not compatible with libertarian free will. Some libertarian explanations involve invoking panpsychism, the theory that a quality of mind is associated with all particles, and pervades the entire universe, in both animate and inanimate entities. Other approaches do not require free will to be a fundamental constituent of the universe; ordinary randomness is appealed to as supplying the "elbow room" believed to be necessary by libertarians.
Free volition is regarded as a particular kind of complex, high-level process with an element of indeterminism. An example of this kind of approach has been developed by Robert Kane, where he hypothesises that,
In each case, the indeterminism is functioning as a hindrance or obstacle to her realizing one of her purposes—a hindrance or obstacle in the form of resistance within her will which has to be overcome by effort.
At the time C. S. Lewis wrote Miracles, quantum mechanics (and physical indeterminism) was only in the initial stages of acceptance, but still Lewis stated the logical possibility that, if the physical world was proved to be indeterministic, this would provide an entry (interaction) point into the traditionally viewed closed system, where a scientifically described physically probable/improbable event could be philosophically described as an action of a non-physical entity on physical reality. He states, however, that none of the arguments in his book will rely on this.
Nozick puts forward an indeterministic theory of free will in Philosophical Explanations.
When human beings become agents through reflexive self-awareness, they express their agency by having reasons for acting, to which they assign weights. Choosing the dimensions of one's identity is a special case, in which the assigning of weight to a dimension is partly self-constitutive. But all acting for reasons is constitutive of the self in a broader sense, namely, by its shaping one's character and personality in a manner analogous to the shaping that law undergoes through the precedent set by earlier court decisions. Just as a judge does not merely apply the law but to some degree makes it through judicial discretion, so too a person does not merely discover weights but assigns them; one not only weighs reasons but also weights them. Set in train is a process of building a framework for future decisions that we are tentatively committed to.
The lifelong process of self-definition in this broader sense is construed indeterministically by Nozick. The weighting is "up to us" in the sense that it is undetermined by antecedent causal factors, even though subsequent action is fully caused by the reasons one has accepted. He compares assigning weights in this deterministic sense to "the currently orthodox interpretation of quantum mechanics", following von Neumann in understanding a quantum mechanical system as in a superposition or probability mixture of states, which changes continuously in accordance with quantum mechanical equations of motion and discontinuously via measurement or observation that "collapses the wave packet" from a superposition to a particular state. Analogously, a person before decision has reasons without fixed weights: he is in a superposition of weights. The process of decision reduces the superposition to a particular state that causes action.
Kane is one of the leading contemporary philosophers on free will. Advocating what is termed within philosophical circles "libertarian freedom", Kane argues that "(1) the existence of alternative possibilities (or the agent's power to do otherwise) is a necessary condition for acting freely, and that (2) determinism is not compatible with alternative possibilities (it precludes the power to do otherwise)". It is important to note that the crux of Kane's position is grounded not in a defense of alternative possibilities (AP) but in the notion of what Kane refers to as ultimate responsibility (UR). Thus, AP is a necessary but insufficient criterion for free will. It is necessary that there be (metaphysically) real alternatives for our actions, but that is not enough; our actions could be random without being in our control. The control is found in "ultimate responsibility".
Ultimate responsibility entails that agents must be the ultimate creators (or originators) and sustainers of their own ends and purposes. There must be more than one way for a person's life to turn out (AP). More importantly, whichever way it turns out must be based in the person's willing actions. As Kane defines it,
UR: An agent is ultimately responsible for some (event or state) E's occurring only if (R) the agent is personally responsible for E's occurring in a sense which entails that something the agent voluntarily (or willingly) did or omitted either was, or causally contributed to, E's occurrence and made a difference to whether or not E occurred; and (U) for every X and Y (where X and Y represent occurrences of events and/or states) if the agent is personally responsible for X and if Y is an arche (sufficient condition, cause or motive) for X, then the agent must also be personally responsible for Y.
What allows for ultimacy of creation in Kane's picture are what he refers to as "self-forming actions" or SFAs — those moments of indecision during which people experience conflicting wills. These SFAs are the undetermined, regress-stopping voluntary actions or refraining in the life histories of agents that are required for UR. UR does not require that every act done of our own free will be undetermined and thus that, for every act or choice, we could have done otherwise; it requires only that certain of our choices and actions be undetermined (and thus that we could have done otherwise), namely SFAs. These form our character or nature; they inform our future choices, reasons and motivations in action. If a person has had the opportunity to make a character-forming decision (SFA), they are responsible for the actions that are a result of their character.
Randolph Clarke objects that Kane's depiction of free will is not truly libertarian but rather a form of compatibilism. The objection asserts that although the outcome of an SFA is not determined, one's history up to the event is; so the fact that an SFA will occur is also determined. The outcome of the SFA is based on chance, and from that point on one's life is determined. This kind of freedom, says Clarke, is no different than the kind of freedom argued for by compatibilists, who assert that even though our actions are determined, they are free because they are in accordance with our own wills, much like the outcome of an SFA.
Kane responds that the difference between causal indeterminism and compatibilism is "ultimate control — the originative control exercised by agents when it is 'up to them' which of a set of possible choices or actions will now occur, and up to no one and nothing else over which the agents themselves do not also have control". UR assures that the sufficient conditions for one's actions do not lie before one's own birth.
Galen Strawson holds that there is a fundamental sense in which free will is impossible, whether determinism is true or not. He argues for this position with what he calls his "basic argument", which aims to show that no-one is ever ultimately morally responsible for their actions, and hence that no one has free will in the sense that usually concerns us.
In his book defending compatibilism, Freedom Evolves, Daniel Dennett spends a chapter criticising Kane's theory. Kane believes freedom is based on certain rare and exceptional events, which he calls self-forming actions or SFA's. Dennett notes that there is no guarantee such an event will occur in an individual's life. If it does not, the individual does not in fact have free will at all, according to Kane. Yet they will seem the same as anyone else. Dennett finds an essentially indetectable notion of free will to be incredible.
Frankfurt counterexamples (also known as Frankfurt cases or Frankfurt-style cases) were presented by philosopher Harry Frankfurt in 1969 as counterexamples to the "principle of alternative possibilities" or PAP, which holds that an agent is morally responsible for an action only if they have the option of free will (i.e. they could have done otherwise).
The principle of alternate possibilities
The principle of alternate possibilities forms part of an influential argument for the incompatibility of responsibility and causal determinism, as detailed below:
- PAP: An agent is responsible for an action only if said agent is free.
- An agent is free only if causal determinism is false.
- Therefore, an agent is responsible for an action only if causal determinism is false.
Traditionally, compatibilists (defenders of the compatibility of moral responsibility and determinism, like Alfred Ayer and Walter Terence Stace) try to reject premise two, arguing that, properly understood, free will is not incompatible with determinism. According to the traditional analysis of free will, an agent is free to do otherwise when they would have done otherwise had they wanted to do otherwise. Agents may possess free will, according to the conditional analysis, even if determinism is true.
From the PAP definition "a person is morally responsible for what they have done only if they could have done otherwise", Frankfurt infers that a person is not morally responsible for what they have done if they could not have done otherwise — a point with which he takes issue: our theoretical ability to do otherwise, he says, does not necessarily make it possible for us to do otherwise.
Frankfurt's examples are significant because they suggest an alternative way to defend compatibilism, in particular by rejecting the first premise of the argument. According to this view, responsibility is compatible with determinism because responsibility does not require the freedom to do otherwise.
Frankfurt's examples involve agents who are intuitively responsible for their behavior even though they lack the freedom to act otherwise. Here is a typical case:
Donald is a Democrat and is likely to vote for the Democrats; in fact, only in one particular circumstance will he not: that is, if he thinks about the prospects of immediate American defeat in Iraq just prior to voting. Ms. White, a representative of the Democratic Party, wants to ensure that Donald votes Democratic, so she secretly plants a device in Donald's head that, if activated, will force him to vote Democratic. Not wishing to reveal her presence unnecessarily, Ms White plans to activate the device only if Donald thinks about the Iraq War prior to voting. As things happen, Donald does not think about the Democrats' promise to ensure defeat in Iraq prior to voting, so Ms White thus sees no reason to activate the device, and Donald votes Democratic of his own accord. Apparently, Donald is responsible for voting Democratic in spite of the fact that, owing to Ms. White's device, he lacks freedom to do otherwise.
If Frankfurt is correct in suggesting both that Donald is morally responsible for voting Democratic and that he is not free to do otherwise, moral responsibility, in general, does not require that an agent have the freedom to do otherwise (that is, the principle of alternate possibilities is false). Thus, even if causal determinism is true, and even if determinism removes the freedom to do otherwise, there is no reason to doubt that people can still be morally responsible for their behavior.
Having rebutted the principle of alternate possibilities, Frankfurt suggests that it be revised to take into account the fallacy of the notion that coercion precludes an agent from moral responsibility. It must be only because of coercion that the agent acts as they do. The best definition, by his reckoning, is this: "[A] person is not morally responsible for what they have done if they did it only because they could not have done otherwise."
- Actual idealism
- Bayesian inference
- Benjamin Libet
- Free will theorem
- Ilya Prigogine
- Many-worlds interpretation
- Newcomb's paradox
- Philosophical zombie
- Strawson, Galen (1998, 2004). Free will. In E. Craig (Ed.), Routledge Encyclopedia of Philosophy. London: Routledge. Retrieved July 31, 2009
- Strawson, Galen (1998, 2004). Free will (section 2). In E. Craig (Ed.), Routledge Encyclopedia of Philosophy. London: Routledge. Retrieved July 31, 2009. "These anti-compatibilists or incompatibilists divide into two groups: the libertarians and the no-freedom theorists or pessimists about free will and moral responsibility."
- Timpe, Kevin (2006) Free Will in Feiser, J and Dowden, B (Eds.) 'Internet Encyclopedia of Philosophy'. Retrieved on July 31, 2009 "Other incompatibilists think that the actual world is not deterministic and that at least some of the agents in the actual world have free will. These incompatibilists are referred to as "libertarians" [see Kane (2005), particularly chapters 3 and 4]."
- Strawson, Galen (1998, 2004). Free will (section 2). In E. Craig (Ed.), Routledge Encyclopedia of Philosophy. London: Routledge. Retrieved July 31, 2009. "They [libertarians] hold (1) that we do have free will, (2) that free will is compatible with determinism, and (3) that determinism is therefore false."
- Nichols, Shaun: The Rise of Compatibilism: A Case Study in the Quantitative History of Philosophy
- Nozick, Robert. Philosophical Explanations. 1981: Harvard University Press.
- Dennett, D. Freedom Evolves.Viking Books, February, 2003 ISBN 0-670-03186-0
- Strawson, Galen. "Free Will" in the Routledge Encyclopedia of Philosophy, ed. Edward Craig (1998); "The Bounds of Freedom" in The Oxford Handbook of Free Will, ed. Robert Kane (2002).
- William Belsham, "Essays", printed for C. Dilly, 1789; original from the University of Michigan, digitized May 21, 2007, p.11.
- Oxford English Dictionary definition of libertarianism.
- Kane, Robert; John Martin Fischer; Derk Pereboom; Manuel Vargas (2007). Four Views on Free Will (Libertarianism). Oxford UK: Blackwell Publishing. p. 39. ISBN 1-4051-3486-0.
- Lewis, C.S. (1947). Miracles. p. 24. ISBN 0-688-17369-1.
- Kane, R. (ed.) Oxford Handbook of Free Will
- Information Philosophers "Robert Kane is the acknowledged dean of the libertarian philosophers writing actively on the free will problem."
- Kane (ed.): Oxford Handbook of Free Will, p. 11.
- Kane: "Free Will" in Free Will, p. 224.
- Kane: "Free Will" in Free Will, p. 243.
- Frankfurt, Harry (1969). "Alternate Possibilities and Moral Responsibility". Journal of Philosophy. 66: 829–39. doi:10.2307/2023833. JSTOR 2023833.
- Ayer, A. J. (1954) “Freedom and Necessity in Philosophical Essays, London: Macmillan.
- Frankfurt, 1969. p. 829.
- Frankfurt: "Alternate Possibilities and Moral Responsibility" in Feinberg; Shafer-Landau: Responsibility & Responsibility, p. 488.
- Randolph Clarke Libertarian Accounts of Free Will. Oxford University Press: New York, 2003. ISBN 0-19-515987-X
- Robert Kane The Significance of Free Will. Oxford University Press: New York, 1998. ISBN 0-19-512656-4
- Stanford Encyclopedia of Philosophy
- Peter Van Inwagen: The Mystery Of Metaphysical Freedom
- Collection of papers on various aspects of Free Will and Determinism hosted by Ted Honderich
- Information Philosopher
- MindPapers Collection of articles on Libertarianism about Free Will