Free will and determinism
Michael Lacewing
enquiries@alevelphilosophy.
co.uk
Determinism defined
• Syllabus: ‘the belief that a determinate set
of conditions can only produce one possible
outcome given fixed laws of nature’
• Universal causation: every event – everything
that happens or occurs – has a cause
– Even if we don’t know the cause, we don’t allow
that something ‘just happened’
• Causal necessity: given the total set of
conditions under which the cause occurs,
only one effect is possible
Physical determinism
• Everything that happens in the physical
universe is causally determined by the state
of the universe + laws of nature.
– E.g. every decision is determined by the
previous state of my brain
• If we could know the position of every
particle in the universe + the laws of nature,
every future physical event could be
predicted in principle.
– E.g. every movement of your body
Actions as events
• Our actions are events.
• Therefore, they have causes.
• Given the causes they have, no action is
possible other than what we actually do.
• If we couldn’t do any other action, then we
do not have free will, e.g. to choose
between doing different actions.
Psychological determinism
• Comes in degrees
• Strong: every psychological event is causally
determined by previous events + laws of
psychology
– But (almost) no strict laws of psychology have
been discovered
• Weak: patterns of psychological events,
including decisions, are determined by
previous experiences
– Many influences on our decisions are outside our
control
Character determinism
• Many traits of character are not chosen; but
traits of character allow us to predict what
people choose.
• Not being able to predict what they do
doesn’t make them more free.
• Aren’t people most free when they act ‘in
character’?
Prediction and freedom
• Being able to predict what
someone will do isn’t
enough to show that they
aren’t free.
– Preferences
– Character traits
• It depends on whether the
basis for prediction rules
out the possibility the
action can’t happen.
Actions, events and bodily
movements
• There is an important difference between how
we explain what we do (actions) and things that
just happen (natural events).
– Compare explanations of crop circles – how and why
• We also contrast actions with unintentional
bodily movements
– Compare pushing someone and accidentally falling
into them
• With actions, we cite reasons rather than
causes.
Reasons and causes
• Causes precede their effects in time.
Reasons do not need to.
– If I give money to charity because it helps
the needy, ‘charity helps the needy’ is not
something ‘occurs’ before I give money (it
doesn’t occur in time at all).
• Reasons can cite purposes – ‘in order
to…’. But a causal explanation cannot
cite a purpose.
Reasons and causes
• Reasons can be ‘good’ or ‘bad’. Causes cannot.
– Not anything can be a (good) reason to act in a
certain way: ‘I hit him because his socks are purple’.
Anything can be a cause of anything, logically
speaking.
• When we identify a cause, then the effect must
exist. When we identify a reason, the action it is
a reason for does not have to have occurred.
– ‘The cigarette caused the fire’ v. ‘Keeping warm is a
reason to start a fire’
Actions and bodily
movements again
• Actions are not bodily movements.
• Bodily movements are identified physically, and
can be given physical causal accounts.
• Actions are identified by reasons.
• What action a particular bodily movement
serves depends on the context.
– Raising one’s arm
• Many different bodily movements may serve the
same action
– Paying a bill
Moral responsibility
• Intuitively, we only blame someone if
they could have refrained from acting
as they did.
– If you cannot save someone drowning, you
are not morally responsible for not
helping.
• If determinism is true, can we have
moral responsibility?
Ought implies can
• If there is something that you ought to
do, then you are able to do it.
• So if you ought to have acted
differently, then you could have acted
differently.
• If you could not have acted differently,
it makes no sense to say that you ought
to have acted differently.
Compatibilist defences of
moral responsibility
• Accept that ought implies can and argue that there
is a relevant sense in which a person could have
acted differently, even though determinism is true,
and so they are morally responsible.
• Argue that issues of determinism and ‘ought implies
can’ are irrelevant to moral responsibility.
• Reject the ‘ought implies can’ principle, so the fact
that a person cannot do anything else does not
mean that they are not morally responsible for it.
