The problem of free will has always been a subject of controversy in philosophy. The debate on free will—defined in this essay as the autonomous ability to choose between various options in accordance with one’s desires and intentions—can be divided into determinism and indeterminism. Determinism is the doctrine that all events are preordained by factors beyond human control, while indeterminism propounds the contrary notion. Following these definitions, a purely determinist approach maintains that free will and determinism are dichotomous and therefore incompatible, with the opposite persisting for an indeterminist stance. In this essay, a libertarian (indeterminist) position will be adopted based on the notion that the results of the Libet experiments provide insufficient proof against free will, which will be substantiated by addressing the inherent weaknesses in Libet's experimental approach and interpretation of free will.
The Libet experiments were conducted in the 1980s by Benjamin Libet as a challenge to free will from science. The experiment aimed to determine the relationship between readiness potential—a measure of brain activity leading up to volitional muscle movement—and the conscious decision to execute an action voluntarily. In order to achieve this, subjects were asked to observe a clock and flex their wrist when the conscious urge to do so arose, while simultaneously reporting the time they experienced this. The time difference between the conscious and unconscious decision to act—measured by the readiness potential through an electroencephalogram (EEG)— was subsequently calculated, with results illustrating that the readiness potential occurred approximately 0.4 seconds before subjects became aware of their intention to act. This appears to confirm the determinist school of thought: if the unconscious action precedes the conscious intention, then the causal efficacy of conscious will is denied and wholly epiphenomenal, therefore holding severe implications for the issue of moral responsibility.
This determinist claim can be rejected by examining the implications of the readiness potential in further detail. According to Libet, ‘freely voluntary acts are preceded by a specific electrical charge in the brain (the “readiness potential”)’, which is a conditional statement leading to the likely conclusion ‘that the volitional process is initiated unconsciously’ (Libet, 2005: pp. 1). The argument structure follows as such:
Conditional statement: If there is a readiness potential, then the volitional process is initiated unconsciously.
Empirical observation: There is a readiness potential.
Conclusion: The volitional process is initiated unconsciously.
While it is natural to conclude that the causality between the readiness potential and unconscious intention to act is indicative of determinism, there is a post hoc logical fallacy present, which is the assumption that if event Y follows event X, then event X is the cause of event Y. When substituted with the premise that the unconscious action follows the readiness potential, it can be concluded using the fallacy that the latter is the cause of the former. However, this is erroneous: although the readiness potential may be a cause of volitional action, the possibility that there are alternative causes controlled by the willpower of the subject is not eliminated, therefore undermining the determinist belief that factors beyond human control antecede all actions. Furthermore, the storage of EEG data (readiness potential) is triggered iff wrist movement is initiated by the subject (Libet, 2005); as such, it logically follows that in the absence of wrist movement, there will be no EEG data recorded and vice versa. However, this disregards the possibility of the readiness potential occurring without being succeeded by wrist movement: if such an event transpires without record, then it is insufficient to conclude that the readiness potential is a cause of the volitional process (Mele, 2009). The readiness potential may hence reflect the urge to perform a voluntary action (Mele, 2011: pp. 9). Even if Libet’s argument is accepted, an urge is not equivalent to the intention to act upon an urge, which therefore does not impede free will; the readiness potential merely reflects a state of readiness for the execution of a freely willed action.
A determinist may contend this statement by referring to the conscious veto to counter the implications of the readiness potential, which is capable of ‘stopping or vetoing the final progress of the volitional process so that no actual muscle action ensues’ (Libet, 2005: pp. 6). However, the conscious veto is argued to be free will in an attenuated sense, as the conscious veto only permits the blocking of predetermined actions. Furthermore, the possibility of the conscious veto being initiated by unconscious neural activity is not eliminated, which suggests that all actions—including intentions to perform or veto an act—are epiphenomenal: ‘the choice to veto would become an unconscious choice of which we become conscious, rather than a consciously causal event’ (Libet, 2005: pp. 8). This holds significant implications for moral responsibility: since free will is a plausible necessary condition for this, an agent not acting on their own volition cannot be held morally responsible for their actions.
However, this essay will disprove the determinist claims that (1) the conscious veto results from unconscious neural activity, and (2) the determinist argument remains valid because the conscious veto only facilitates the blocking of predetermined actions.
To refute claim (1), the following argument will be proposed:
Empirical observation: Freely voluntary acts are preceded by the readiness potential.
Descriptive claim: The conscious veto is a freely voluntary act.
Conclusion: The conscious veto is preceded by the readiness potential.
It is evident from Libet’s experimental account that premises (1) and (2) are sound: ‘the brain process (RP) to prepare for this voluntary act began […] before the appearance of the conscious will to act’, therefore verifying premise (1), while the conscious veto is described as a ‘conscious control action’, therefore verifying premise (2) (Libet, 2005: pp. 5-9). As such, if these premises were to be accepted as sound, then it is only logical to assume that the conscious veto would also be preceded by the readiness potential due to its nature as a volitional act.
From this, the determinist’s conclusion that the conscious veto results from unconscious neural activity is invalid, as this would entail the rejection of premise (2). This is evident from the determinist claim that the readiness potential disproves free will, which illustrates the acceptance of premise (1): freely voluntary acts are preceded by the readiness potential, which leads to the conclusion against free will, as it is incompatible with the readiness potential (a determinist concept). However, using this line of argumentation, it is impossible for determinists to reject premise (2) if they accept premise (1), as the nature of the conscious veto—a ‘conscious control action’, and, through implication, a freely voluntary act—does not follow logically from premise (1). As such, it is also impossible for a determinist to arrive at his conclusion, as this presumes the acceptance of premise (2), which invalidates its denial in the determinist’s argument provided.
To refute claim (2), the notion that all events are predetermined must be challenged. While this is impossible to prove with certainty, event-causal libertarianism provides the strongest contention against why determinism may not be correct. Event-causal libertarianism asserts that events possess a causal quality without being necessarily predetermined; this is because soft causality maintains that events are solely determined by statistics or probability. For example, the Born Rule states that the location of a given particle is dependent on probability in quantum mechanics, while radioactive decay is a purely statistical process in nuclear physics. As such, although determinism cannot be rejected, there is also no evidence to deny event-causal libertarianism, therefore illustrating the unsubstantiated nature of claim (2) and diffusing the threat against free will.
There are also limitations in Libet’s experimental procedure that lead to the conclusion that the results obtained provide insufficient proof against free will. Most evident is that the experiment relies heavily on introspection: because of the subjective nature of recalling the time of awareness subjects experienced the conscious urge to flex their wrist, it is impossible to substantiate such accounts, therefore decreasing the reliability of data. Moreover, Risto Näätänen remarks that the spontaneous flexing of the wrist would have been ‘decided by the subject on receiving the experimental instructions’ (Näätänen, 1985: pp. 549). Because participants received the direction to do so upon consenting to the experiment, Näätänen claims that participants would have already made the conscious decision to flex their wrist prior to executing the action, therefore invaliding Libet’s conclusion, which surmised the opposite.
In conclusion, the Libet experiments provide insufficient evidence against free will as a result of weaknesses in the experimental approach and interpretation of free will. While determinists may object that the relationships between the readiness potential, conscious veto and conscious intention to act are indicative of determinism, this is simply untrue, as this essay has outlined. While the results of the Libet experiments remain controversial to the present day, they can only be generalised to decisions incomparable to situations