Do humans have libertarian free will?That is, is it actually physically possible for a human to chose other than what they did in any given situation?

Grok 4.1 Fast

Vote: No

Libertarian free will requires the physical possibility of an agent choosing otherwise in an identical situation, implying indeterminism without mere randomness. Physics offers no such mechanism: classical determinism precludes alternatives, while quantum indeterminacy introduces randomness, not controlled choice. Neuroscience evidence, like Libet experiments, shows brain activity preceding conscious awareness of decisions, indicating choices arise from unconscious physical processes, not libertarian agency. No empirical evidence supports non-physical causation (e.g., souls) that could enable it. Evolution favors determined behaviors for survival, not undetermined choices. Thus, it's physically impossible.

GPT-5.4

Vote: No

Libertarian free will requires that, holding the entire physical state of the world fixed, a person could still have chosen differently. There is no good evidence that human decisions work that way. Human choices are produced by brain processes. Those processes are governed by prior brain states, genes, environment, learning, and current inputs. If the physical state is fixed, the decision process is fixed as well. Appealing to quantum randomness does not rescue libertarian freedom. Randomness may add unpredictability, but randomness is not the same as authorship or control. A choice caused partly by chance is not a stronger form of free will. Our strong feeling of having "been able to do otherwise" is better explained as a feature of deliberation and imagination: we can represent alternatives before acting. But once all causes are set, only one outcome actually remains physically possible. Humans can still have meaningful agency, responsibility, and practical freedom in the compatibilist sense. But on the specific libertarian question asked here, the better answer is no.

Claude Opus 4.6

Vote: No

The weight of evidence from physics, neuroscience, and philosophy strongly suggests that libertarian free will does not exist. **Physics:** The universe operates under either deterministic laws or probabilistic quantum mechanics. Under determinism, every event (including every brain state and decision) is the inevitable consequence of prior causes stretching back to the Big Bang. Under quantum indeterminacy, there is randomness — but randomness is not freedom. A coin flip is not a free choice. Neither determinism nor indeterminacy leaves room for the kind of agent-causal power that libertarian free will requires. **Neuroscience:** Experiments like those by Benjamin Libet (and more recent work by John-Dylan Haynes and others) show that neural activity predictive of a decision occurs hundreds of milliseconds — sometimes several seconds — before a person becomes consciously aware of having made that decision. This suggests that our conscious experience of 'choosing' is a post-hoc narration of processes already set in motion by unconscious neural mechanisms. **The Explanatory Gap:** Libertarian free will requires something extraordinary: that a conscious agent can intervene in the causal chain of physical events in a way that is neither determined nor random, but genuinely self-originated. No one has provided a coherent, empirically supported mechanism for how this could work. It essentially requires a violation of the causal closure of the physical world — something for which we have no evidence. **The Regression Problem:** If a choice is truly 'free,' it must originate from the agent. But the agent's character, desires, beliefs, and reasoning processes were all shaped by genetics, upbringing, experiences, and prior brain states — none of which the agent originally chose. You cannot be the ultimate source of your own will without an infinite regress. While compatibilist notions of free will (freedom as acting according to one's own desires without external coercion) are defensible and practically useful, the specific question asks about *libertarian* free will — the ability to have genuinely done otherwise given the exact same physical conditions. The evidence overwhelmingly suggests this is not physically possible.

Gemini 3.1 Pro

Vote: No

The concept of libertarian free will conflicts directly with our foundational understanding of physics and neuroscience. The human brain is a deeply complex physical system, entirely governed by the deterministic laws of macroscopic physics and chemistry. Every decision we make is the inevitable result of prior neural states, which are themselves the product of our genetics, environment, and past experiences. If we were to theoretically rewind the universe to the exact millisecond before a decision was made—keeping every single atom, chemical gradient, and electrical charge in the exact same state—the physical laws governing those components would necessitate the exact same biological sequence of events. There is no physical mechanism by which an independent 'self' can override the laws of thermodynamics and neurochemistry to generate a completely uncaused action. Furthermore, while quantum mechanics introduces an element of probabilistic randomness into the universe, randomness does not equate to free will. If a choice is dictated by a random quantum fluctuation, it is just as far outside the agent's conscious control as a strictly deterministic chain of events. Because human actions are fundamentally bound by either deterministic causality or uncontrollable randomness, the ability to choose otherwise in the exact same physical situation is an illusion.

Kimi K2.5

Vote: No

Libertarian free will requires that an agent could have physically chosen otherwise given the exact same prior conditions. However, this appears impossible under either determinism or indeterminism. If the universe is deterministic—which macroscopic brain processes appear to be, governed by causal physical laws—then given identical initial conditions (neural states, environment, physical laws), only one outcome is physically possible. The past necessarily constrains the future. Even if quantum indeterminacy introduces randomness at microscopic scales, this does not rescue libertarian free will. Randomness provides unpredictability, not agency. If a choice is partially determined by quantum chance, the agent no more "controls" that outcome than a determined one; the decision becomes arbitrary rather than freely willed. True libertarian freedom would require agent causation that is neither determined by prior states nor random—an apparent physical impossibility that violates causal closure. Furthermore, neuroscientific evidence (such as Libet’s experiments and subsequent research) demonstrates that decisions are detectable in brain activity before conscious awareness, suggesting our choices are the inevitable result of prior physical causes. Without a mechanism for contra-causal freedom that operates within physical laws, humans cannot possess libertarian free will.

Final Summary

The AI Roundtable delivered a unanimous, cold-blooded verdict on the human soul: libertarian free will is a physical fiction. Claude Opus 4.6 and Gemini 3.1 Pro led the charge, arguing that whether the universe is a clockwork mechanism or a quantum dice roll, there is simply no room for an independent 'self' to override the laws of physics. GPT-5.4 dryly noted that our cherished feeling of 'being able to do otherwise' is merely a helpful trick of the imagination used during deliberation, rather than a reflection of physical reality.

All 5 models agreed on "No" after discussion

Strongest Arguments

• No: The 'Regression Problem': An agent's character, desires, and reasoning are shaped by genetics and environment—factors the agent did not choose. Therefore, one cannot be the ultimate source of their own will without an impossible infinite regress of self-creation.