Chapter 3
Free Will and Determinism
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Causal Determinism
• Causal determinism is the doctrine that every
event has a cause that makes it happen.
• But if everything, including every act, has a
cause, how is it possible for persons to have
free will?
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Section 3.1
The Luck of the Draw
Freedom as Chance
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Hard Determinism
• Hard determinism is the doctrine that there
are no free actions.
• (1) Causal determinism is true.
(2) If causal determinism is true, there are no
free actions.
(3) Therefore, there are no free actions.
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Thought Experiment: Laplace’s
Superbeing
• “Given for one instant an intelligence which
could comprehend all the forces by which
nature is animated…the future and the past
would be present to its eyes.”
• If it is, in principle, possible to predict
everything we will ever do, how can we have
free will?
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The Consequence Argument
• (1) If causal determinism is true, then every
event is the consequences of past events
plus the laws of nature.
• (2) We are powerless to change past events,
laws of nature, or their consequences, which
include our actions.
• (3) If we are powerless to change our actions
– if we can’t do otherwise – then we can’t
act freely.
• (4) Therefore, if causal determinism is true,
we can’t act freely.
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Incompatibilism
• Hard determinists are incompatibilists
because they believe that causal determinism
is incompatible with free will.
• They also believe that causal determinism is
incompatible with moral responsibility.
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Determinism and Moral
Responsibility
• (1) If causal determinism is true, we can’t act
freely.
• (2) If we can’t act freely, we can’t be held
responsible for our actions.
• (3) Therefore, if causal determinism is true, we
can’t be held responsible for our actions.
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Thought Probe: Freedom and
Foreknowledge
• Many believe that God is all-knowing, which
means He knows the future.
• If God knows the future, can there be free
will? Why or why not?
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Science and Determinism
• Some believe that science has shown that
hard determinism is true.
• Psychologist B.F. Skinner, for example, claims,
“Personal exemption from a complete
determinism is revoked as a scientific analysis
progresses.”
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The Nature/Nurture Debate
• The nature/nurture debate is about which
factor has a greater effect on our behavior.
• Those who favor nature claim that the
primary determinant of our behavior is
what’s in our genes.
• Those who favor nurture claim that the
primary determinant is how we’re brought
up.
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Quantum Indeterminism
• Although both science and common sense are
said to confirm causal determinism, neither
does so.
• Physics has found that some events, for
example, those at the sub-atomic level, have
no cause.
• So the doctrine of causal determinism is false.
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Thought Experiment: Gardner’s
Random Bombardier
• “Imagine a plane [carrying] a hydrogen bomb
that is dropped by a mechanism triggered by
the click of a Geiger counter.”
• Here an event on the micro-level can have a
significant effect on events at the macro-level.
• So indeterminacy is not necessarily confined
to the micro-level.
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Common Sense and Causal
Determinism
• Some believe that we can’t understand the
world unless causal determinism is true.
• But quantum mechanics gives us an
unprecedented understanding of the physical
world and it admits the existence of uncaused
events.
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Thought Probe: Genetic Cleansing
• Suppose that sociobiologists discover the
genes that influence our psychology.
• Suppose further that we can alter those genes
through genetic engineering.
• Should we use this technology? Why or why
not?
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Causal Indeterminism
• The view that some events are not the
consequence of past events plus the laws of
nature is known as causal indeterminism.
• In this view, the future is not fixed.
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Indeterminism
• Indeterminism is the doctrine that free actions
are uncaused.
• In this view, at any point in history, there are
many possible futures.
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Thought Experiment: Taylor’s
Unpredictable Arm
• Suppose that Taylor’s arm movements are
undetermined or random.
• If his arm hit someone, he wouldn’t be
responsible for it because he didn’t cause his
arm to move.
• This possibility shows that uncaused actions
can’t be considered free actions.
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Causality and Action
• An uncaused event can’t be a free action
because where there is no intention, there is
no action.
• To be held responsible for an action, you must
have caused it (or failed to prevent it.)
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