A philosopher argues that quantum indeterminacy in neural processes means your decisions are not fully determined, and therefore you have genuine libertarian free will. The strongest objection to this argument is:
AQuantum events are too small to affect anything as large as a neural firing
BNeuroscience has shown that all decisions are determined before conscious awareness
CIf the decision is not fully determined, then to that degree it is random — and random events are not controlled by the agent
DQuantum indeterminacy only applies to isolated particles in laboratory conditions, not biological systems
This is the 'luck objection,' the central challenge for libertarian theories. Replacing determinism with indeterminism doesn't obviously give you free will — it just makes your choices partly random. A random event is something that simply happens; it is not controlled by the agent any more than a determined event is. Libertarians must explain how indeterminism in a neural process amounts to the agent genuinely controlling their choice, not just having the outcome left to chance.
Question 2 Multiple Choice
Agent causation theories of libertarian free will differ from event-causal indeterminist theories primarily in that:
AAgent causation requires determinism; event-causal indeterminism requires that determinism is false
BAgent causation holds that persons as substances are irreducible causal origins, not reducible to a chain of prior events
CAgent causation is fully compatible with physicalism; event-causal theories are not
DAgent causation denies that neural processes play any causal role in free decisions
Agent causation (Chisholm, O'Connor) holds that the free agent — as a persisting substance — is itself a causal power that initiates action, not reducible to any prior event-causal chain. The agent causes the action from themselves. Event-causal indeterminist theories (Kane) locate the freedom in indeterminate events within neural processes, arguing that the agent's deliberation is causally engaged with those undetermined events. Both are incompatibilist, both require indeterminism, but they differ on what kind of thing does the causing.
Question 3 True / False
In everyday speech, 'libertarian free will' refers to the political philosophy view that individuals should be free from government coercion.
TTrue
FFalse
Answer: False
These are two entirely distinct uses of the word 'libertarian.' Libertarian free will is a position in metaphysics about the relationship between freedom, causation, and determinism — specifically, the incompatibilist view that agents have genuine free will, which requires that their free actions are not fully determined by prior causes. It has no connection to political libertarianism. Students frequently confuse these, so it is worth distinguishing sharply.
Question 4 True / False
On a libertarian account of free will, given the exact same prior history and physical laws, the same agent could have made a different choice — there is genuine branching in the space of possibilities, not just uncertainty about a fixed outcome.
TTrue
FFalse
Answer: True
This is the defining modal claim of libertarian free will. In the possible-worlds framework, libertarians hold that adjacent possible worlds with identical prior history and laws contain different decisions by the agent — genuine indeterministic branching, not merely our epistemic uncertainty about a determined outcome. This is precisely what distinguishes libertarianism from compatibilism: compatibilists can accept 'could have done otherwise' only in the sense 'would have done otherwise if conditions had been different,' not in the libertarian sense of 'same conditions, different outcome.'
Question 5 Short Answer
What is the 'luck objection' to libertarian free will, and why does simply pointing to quantum indeterminacy in the brain not resolve it?
Think about your answer, then reveal below.
Model answer: The luck objection holds that if a decision is not fully determined by prior causes, then to that degree it is random — and random events just happen without being controlled by the agent. Quantum indeterminacy doesn't help because quantum random events are paradigmatically uncontrolled; they don't become the agent's own choice just by occurring in the brain.
Libertarians must explain how the indeterminate moment of choice is genuinely the agent's doing rather than a coin flip that happened to occur inside them. Agent causation tries to solve this by positing the agent as a special irreducible causal power. Event-causal theories (Kane) argue the agent's deliberative states are causally entangled with the indeterminate neural events, making the outcome authentically the agent's even though undetermined. Neither solution is universally accepted, and the luck objection remains the most pressing challenge for libertarian theories.