What are Benjamin Libet's experiments, and do they negate free will as some scientists interpret them?

The experiments of Benjamin Libet (1916-2007) — an American neuroscientist — are among the most controversial experiments in the history of modern neuroscience. His experiments conducted in the 1980s on the "Bereitschaftspotential/Readiness Potential" sparked a philosophical and scientific debate that continues to this day about the nature of free will and its relationship to neural activity.

Inadequate responses to avoid

From some neural determinists: "Libet's experiments scientifically proved that free will is an illusion" — hasty conclusion. Libet himself did not reach this absolute conclusion. "The brain decides 550 milliseconds before consciousness, therefore there is no freedom" — harmful oversimplification of the experiment's complexity and its multiple interpretations.

From some defenders of freedom: "The experiments measure simple movements, not complex moral decisions" — partially correct but does not invalidate the question posed. "Experimental science cannot study metaphysical freedom" — evasion of the real challenge posed by the experiments.

Design of Libet's basic experiments

The classic experiment (1983): The participant sits in front of a special clock with a hand that rotates rapidly. They are asked to move their wrist at any time they wish, and to record the moment they "felt" the urge to move (W-time). Simultaneously, the brain's electrical activity (EEG) and muscle activity (EMG) are recorded.

The surprising results: The readiness potential (RP) — neural activity in the supplementary motor cortex — begins about 550 milliseconds before the actual movement. But consciousness of the desire to move (W) only appears about 200 milliseconds before the movement. In other words: the brain "prepares" for movement before the person becomes aware of their desire to move by about 350 milliseconds.

Libet's own interpretation

Libet did not conclude the complete elimination of freedom. He proposed the "Free Won't" model: while it's true that unconscious processes initiate the action, consciousness still has about 100-150 milliseconds to exercise "veto rights" on the action. This preserves a role for conscious will, albeit a negative role (prevention) rather than positive (initiation).

Contemporary interpretations and criticisms

1. Methodological criticisms: The accuracy of measuring W-time is questionable. How does a person precisely determine the "moment" the urge appears? Dennett (2003) and others challenged the possibility of this precise determination. Generalizing from simple movements to all types of decisions is an unjustified leap.

2. Reinterpreting the results: Schurger and others (2012) proposed that RP is not a "decision" but a random accumulation of neural activity reaching a threshold. The new model explains the data without assuming an "unconscious decision."

3. Modern expansions: Newer techniques (fMRI, single-neuron recording) allowed for earlier predictions. Soon and others (2008) predicted decisions 7-10 seconds in advance in some cases. However, the prediction accuracy (60%) suggests non-absolute determinism.

4. Distinguishing between types of decisions: Brass & Haggard (2007) distinguished between "what" and "when" decisions. RP is primarily related to action timing, not its content.

The deeper philosophical position

Behind the technical debate lies the philosophical question: what exactly do the experiments prove?

From a Compatibilist perspective: Even if neural processes begin before consciousness, this does not negate freedom. Freedom means acting according to our desires and beliefs, even if these desires result from brain processes. Frankfurt, Dennett, and others developed sophisticated models of compatibilist freedom.

From a Libertarian perspective: Kane and others see that the experiments do not negate the possibility of consciousness affecting neural processes through quantum or emergent mechanisms. Quantum uncertainty may allow for genuine freedom.

From a Hard Determinism perspective: Some philosophers like Pereboom view the experiments as additional evidence for determinism, but they acknowledge these are not the decisive proof.

Recent developments (2010-2024)

1. Criticism of the linear model: Schultze-Kraft and others (2016) showed that people can stop movement even after RP appears, supporting Libet's "free won't" model.

2. Dynamic complexity: Complex systems models show that the relationship between neural activity and decision is non-linear. Statistical prediction does not mean determinism.

3. Reframing the question: Instead of "do we have free will?", the question becomes "what types of freedom are possible within a naturalistic framework?"

Critical conclusion

Libet's experiments revealed the complexity of the relationship between consciousness and action, but they did not settle the philosophical question. Interpretations range from denying freedom to redefining it. The current scientific consensus: the experiments challenge naive models of free will (consciousness initiates everything) but do not prove absolute determinism.

From the perspective of god-database and the method of rational preferability (rajḥān ʿaqlī): these experiments add a dimension to the debate without settling it. The question of freedom and responsibility remains open, requiring integration between scientific data, philosophical analysis, and ethical and religious considerations.

For advanced reading

─ Advanced level: The debate over Schurger's alternative interpretation of RP
─ Libet, "Unconscious Cerebral Initiative" (1985)
─ Mele, Free: Why Science Hasn't Disproved Free Will (2014)
─ The subsection on "Neuroscience of Free Will" on the website