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发帖数: 8336 | 1 Free Will and Determinism
http://www.trinity.edu/cbrown/intro/free_will.html
This is a quick look at issues concerning the nature of free agency. There
are three important questions about free will and determinism, but only one
of them is really a philosophical question. Ayer mentions all three
questions in his opening paragraph (Bailey, p. 558): "It is commonly assumed
that men are capable of acting freely, in the sense that is required to
make them morally responsible, and that human behavior is entirely governed
by causal laws: and it is the apparent conflict between these two
assumptions that gives rise to the problem of the freedom of the will." Ayer
is pointing out that the following three assumptions are jointly
incompatible:
1. people are capable of acting freely
2. determinism is true ("human behavior is entirely governed by causal laws
")
3. acting freely and being causally determined are incompatible
1. Is Determinism True or False?
Here are three more or less equivalent ways of defining determinism:
1. Everything has a sufficient cause. (A "sufficient cause" is a cause
which suffices to insure that the event in question will take place.)
2. The facts about the state of the universe at a given time, together with
the laws of nature, imply the state of the universe at any later time.
3. If one knew enough about the state of the universe at a given time, and
the laws of nature, and had sufficient computational power, one could
predict the state of the universe at any later time.
It should be noted that quantum physics is generally believed to show that
determinism is false. Nevertheless, it remains an interesting issue whether
freedom is compatible with determinism, because (1) it is not clear that
quantum indeterminacies have an effect on human action, and (2) if they do,
it is hard to see how this could be the sort of effect which helps make it
intelligible how we could be free.
It was once thought that whether determinism is true or false was a
philosophical issue that could be settled a priori. However, it seems better
to regard it as an empirical issue which will be settled by physics, not
philosophy.
2. Do we have free will?
This also is a question we can't answer a priori; it requires evidence. (It
seems to be more a question for psychology than for philosophy.)
You might think it could be answered simply by examining our own choices. I
am conscious of making decisions; I then perform the corresponding actions.
Doesn't that prove that I have free will?
Answer: no, it doesn't. It is entirely possible that I could have the
experience of choosing freely even though in fact I never do.
To illustrate this point, consider the following examples from Daniel Wegner
, The Illusion of Conscious Will (MIT Press, 2002).
First, a quotation from an article by Jose Delgado: "In one of our patients,
electrical stimulation of the rostral part of the internal capsule produced
head turning and slow displacement of the body to either side with a well-
oriented and apparently normal sequence, as if the patient were looking for
something. This stimulation was repeated six times on two different days
with comparable results. The interesting fact was that the patient
considered the evoked activity spontaneous and always offered a reasonable
explanation for it. When asked, 'what are you doing?' the answers were, 'I
am looking for my slippers', 'I heard a noise', 'I am restless', and 'I was
looking under the bed'." (Wegner, p. 46.)
Second, an experiment with magnets which influence brain function. "In this
experiment, a stimulation magnet was poised above the participant's head and
aimed in random alternation at the motor area on either side of the brain.
Then the participant was asked to move a finger whenever a click was heard (
the click of the electrical switch setting off the magnet). Participants
were asked to choose freely whether to move their right or left index finger
on each trial. Then the magnet was moved around while they responded.
Although the stimulation led the participants to have a marked preference to
move the finger contralateral to the site stimulated, particularly at short
response times, they continued to perceive that they were voluntarily
choosing which finger to move." (Wegner, pp. 47-48.)
The point I want to make with these examples is not that we don't have free
will. Rather, the point is that we can't prove that we have free will by
pointing out that it seems as though we do. The examples show that it is
quite possible to have the experience of free will even when we don't
actually have free will itself.
3. Is free will compatible with determinism?
This is the key philosophical question. Does determinism rule out the
possibility of free will, or could we be genuinely free even if the universe
is a deterministic place?
It seems that the best way to answer this question is in two stages. First,
we need a plausible analysis of what it means to act freely (or choose
freely). Second, we need to see whether this definition is compatible with
the truth of determinism.
Classification of Views about Free Will
Determinism is true Determinism is false
Free will is compatible
with determinism soft determinism [no name]
(i.e. compatibilism is true)
Free will is not compatible hard determinism libertarianism
with determinism
(i.e. incompatibilism is true ）
Note: the view that there are causal constraints on action, but that our
actions are not entirely determined by these constraints, is not soft
determinism. Rather, it is a version of libertarianism. Determinism is the
view that every event is completely determined by prior causal factors, so
any view that denies this cannot be a version of determinism.
Attempts to Define Freedom
It is interesting to attempt to specify necessary and sufficient conditions
for an action to be free. Incompatibilists (hard determinists and
libertarians) hold that one necessary condition of an action's being free is
that it is not (completely) caused. This clearly does not provide a
sufficient condition, since various subatomic events (e.g. the decay of a
radioactive atom on a particular date) are not completely caused, but are
also not therefore free.
Compatibilists think that in fact not being caused is not only not a
sufficient condition for freedom, but not even a necessary condition. The
basic trouble with the idea that free actions must be uncaused, in their
view, is that, to the extent that an action is uncaused, it seems to be
random: we happen to perform one action, but there is no explanation of why
we performed this action instead of some other. This seems to reduce the
realm of free action to utterly trivial decisions: if I am completely
indifferent as between chocolate and strawberry, then my decision between
the two flavors might be random or arbitrary in the relevant sense. But
the cases in which we are most interested in freedom of action are cases in
which we do have reasons that favor one action over another. It seems that
in such cases there is an explanation of why we perform the action in
question instead of some other action, and the fact that there is an
explanation of the action seems to imply that it is caused. The view of
compatibilists, then, is that free actions are not uncaused actions, but
rather actions that are caused in a particular way.
A first attempt at a compatibilist definition might be this:
1. An action is free if and only if its cause is internal to the agent
rather than external to the agent.
However, this clearly is not a successful definition, since an action can
have internal causes and yet not be free (for example, sneezing has internal
causes but is not a free action). A second attempt might be:
2. An action is free if and only if it is caused by the agent's beliefs and
desires.
This seems much more plausible. However, there still appear to be
counterexamples -- that is, cases in which an action is caused by an agent's
beliefs and desires and yet is not a free action. Apparent counterexamples
include:
•brainwashing (I act because of my beliefs and desires, but my beliefs
and perhaps desires have not been acquired normally, but rather in a sense
forced on me)
•addiction (I act because of my beliefs and desires, but my desires
have been affected by my addiction)
•coercion (I act because of my beliefs and desires, but someone has
manipulated the situation in such a way that the only options open to me are
options I would not normally choose)
•lying (I do something because of my beliefs and desires, but I have
acquired some of the beliefs because someone lied to me)
A compatibilist might argue that the first two counterexamples rest on
mistakes about brainwashing and addiction, and that in the second two cases
we actually are free in the relevant sense. Or the compatibilist might
agree that these are counterexamples to the proposed definition, and try to
construct a more sophisticated definition. Ayer's suggestion is that an
action is free if it is unconstrained; he elaborates this into a definition
as follows (Bailey, p. 562):
3. An action is free iff:
(1) I would have acted differently if I had so chosen;
(2) My action was voluntary (rules out inner constraint, as in
kleptomania);
and
(3) No one compelled me (rules out outer constraint) | n********n
发帖数: 8336 | 2 Determinism, free will and compatibilism
by Tim Harding
The idea that the future is already determined is known in philosophy as
determinism. There are various definitions of determinism available; but in
this essay, I shall use the Stanford Encyclopedia of Philosophy definition,
which is ‘the metaphysical thesis that the facts of the past, in
conjunction with the laws of nature, entail every truth about the future’ (
McKenna, 2009:1.3).
This idea presents a difficult problem for the concept of free will: how can
we make free choices if all our actions are determined by the facts of the
past and the laws of nature? A related but distinct question is: how can we
be held morally responsible for our actions if we have no free will?
Undesirable consequences like these are not sufficient reasons for declaring
determinism to be false; but they can act (and have acted on many
philosophers) as a powerful motivator towards resolving the apparent
conflict between determinism and free will.
Some philosophers, such as Peter van Inwagen have gone as far as arguing
that the existence of moral responsibility entails the existence of free
will (Iredale 2012: 8).[1] There are various other philosophical arguments
in favour of free will – one of these is an apparent paradox known as
Buridan’s Ass. Some scientists, such as Sam Harris argue in favour of
determinism and claim that free will is an illusion. Leading contemporary
philosopher John Searle thinks that the issue has still not been resolved,
despite two centuries of philosophical and scientific debate.
Most people who are neither philosophers nor scientists seem to intuitively
feel that they have free will and so when presented with this dilemma are
more likely to choose free will over determinism (Iredale 2012:13). On the
other hand, in my personal experience, scientists who think in terms of
causes and effects are more likely to side with a determinist view. In this
essay, I intend to argue that a solution to this dilemma lies not in
choosing free will over determinism, nor vice versa; but in the theory that
determinism and free will are compatible – known as compatibilism.
Before going on, let us be clear about what we mean by the term free will.
Clarke & Capes (2013:1) have provided a useful definition:
‘To have free will is to have what it takes to act freely. When an agent
acts freely—when she exercises her free will—it is up to her whether she
does one thing or another on that occasion. A plurality of alternatives is
open to her, and she determines which she pursues. When she does, she is an
ultimate source or origin of her action’.
So what does it take to act freely? Taylor (2012: 40) states that there are
three essential characteristics to free actions. One is able to act freely
only if:
(1) there is no obstacle that prevents you from doing A, and
(2) there is nothing that constrains or forces you to do A, and
(3) one could have done otherwise.
There is a diversity of philosophical views about the relationship between
determinism and free will; but the higher-level taxonomy of these views may
be summarised as follows. Those who hold that determinism and free will
cannot both be true are known as incompatibilists. Within this category,
those who claim that determinism is true – and therefore free will is
impossible – are known as hard determinists. Those who claim that
determinism is false and therefore that free will is at least possible are
known as metaphysical libertarians (not necessarily related to political
libertarians). Those who think that determinism and free will are
compatible are known as compatibilists. There is also a range of sub-
categories within the compatibilist camp; but I will only discuss a couple
of them in this essay. This higher-level taxonomy can be visually described
by the following diagram.
https://yandoo.files.wordpress.com/2013/10/determinismxfreewill-svg1.png
To be more specific, the following set of propositions is described by
McKenna (2009:1.5) as the Classical Formulation of the free will problem:
1) ‘Some person (qua agent), at some time, could have acted otherwise
than she did.
2) Actions are events.
3) Every event has a cause.
4) If an event is caused, then it is causally determined.
5) If an event is an act that is causally determined, then the agent of
the act could not have acted otherwise than in the way that she did’.
This formulation involves a mutually inconsistent set of propositions, and
yet each is consistent with in our contemporary conception of the world,
producing an apparent paradox. How can these inconsistencies be reconciled?
Compatibilists would deny proposition 5). Incompatibilists, on the other
hand, might move in a number of different directions, including the denial
of propositions 1), 3) or 4) (McKenna, 2009:1.5).
According to Taylor (2012: 40), all versions of compatibilism (which he
calls ‘soft determinism’) have three claims in common:
(i) Determinism is true.
(ii) We are free to perform an action A to the extent there are no obstacles
that would prevent us from doing A, and we are not externally constrained (
not forced by external causes) to do A.
(iii) The causes of free actions are certain states, events, or conditions
within the agent himself, e.g., an agent’s own acts of will or volitions,
or decisions, or desires, and so on.
Claim (i) is made in common with hard determinism. Claims (ii) and (iii)
are where the compatibilists part company with the hard determinists and
attempt to explain how free will can be compatible with determinism.
Taylor’s objection to compatibilism is essentially a challenge to Claim (
iii); that is, that the certain states, events, or conditions within the
agent herself are themselves caused by external factors, consistent with
determinism.
My response to Taylor’s objection is that the certain states or conditions
within the agent could include the person’s values, ethics, loyalties,
priorities, and so on. Let us call these states or conditions within the
agent ‘values’. These values may have external causes accumulated over
the agent’s lifetime. The important point is that an agent’s values could
give rise to more than one possible action by the agent, all of which are
consistent with the agent’s values. Let us call these possible consistent
actions ‘options’. When faced with a decision to make, a rational agent
would be likely to consider the options available to her and choose the best
option. In this way, the options available to the agent stem from causes
but the agent is making a free choice within the range of options available.
A simple way of modelling this limited version of free will has been
referred to by some philosophers as a ‘Garden of Forking Paths’ after the
novel of the same name by Jorge Luis Borges (McKenna 2009:2.1; Iredale 2012:
14). In other words, there are alternative paths an agent could choose to
take, but the paths available have been predetermined. Within this model,
the agent meets the criterion of acting of her own free will, because she
could have acted otherwise. Her ability to have acted otherwise is
underwritten by her ability to have selected amongst, or chosen between,
alternative courses of action (McKenna 2009:2.1).
Source: Wikimedia Commons
Garden with forked path (Source: Wikimedia Commons)
Daniel Dennett (2003) has proposed a more elegant version of compatibilism
with an evolutionary basis. Although in the strict physical sense our
actions might be determined, we can still be free in all the ways that
matter, because of the abilities we evolved. Seen this way, free will is
the freedom to make decisions without duress, as opposed to an impossible
and unnecessary freedom from causality itself. To clarify this distinction,
he coins the term ‘evitability’ as the opposite of ‘inevitability’,
defining it as the ability of an agent to anticipate likely consequences and
act to avoid undesirable ones (Dennett 2003:56). Evitability is entirely
compatible with, and actually requires, determinism; because without it, an
agent cannot anticipate likely consequences and avoid them. Dennett
provides us with the following explicit argument:
‘In some deterministic worlds there are avoiders avoiding harms. Therefore
in some deterministic worlds some things are avoided. Whatever is avoided is
avoidable or evitable. Therefore in some deterministic worlds not
everything is inevitable. Therefore determinism does not imply inevitability
’ (Dennett 2003:56).
Dennett (2003:58) also argues that there is a concept of chance that is
compatible with determinism, which has been invoked to explain evolution via
natural selection. Through these means, he endeavours to unyoke
determinism from inevitability (Dennett 2003:60) [2].
In conclusion, I have offered two accounts of how free will may be
compatible with determinism – my own and Daniel Dennett’s. However, I do
not claim that either of these accounts has solved the dilemma. There are
also, of course, many other accounts of compatibilism as well as objections
to them, plus alternative theories such as hard determinism and metaphysical
libertarianism. Indeed, resolving the dilemma between free will and
determinism is very complicated and may be ‘one of the most persistent and
heated deadlocks in Western philosophy’ (Nichols and Knobe 2007:1).
Notes
[1] Peter van Inwagen’s argument that free will is required for moral
judgments is:
1.The moral judgment that you shouldn’t have done X implies that you should
have done something else instead.
2.That you should have done something else instead implies that there was
something else for you to do.
3.That there was something else for you to do implies that you could have
done something else.
4.That you could have done something else implies that you have free will.
5.If you don’t have free will to have done other than X we cannot make the
moral judgment that you shouldn’t have done X (van Inwagen 2009).
[2] For those who would like to read more on this topic, there is an
interesting online debate between Sam Harris and Daniel Dennett. Dennett
critques Harris’ book on Free Will in a review titled Reflections on Free
Will. Then Harris responds to Dennett’s critique in a rejoinder entitled
The Marionette’s Lament.
Bibliography
Clarke, Randolph & Capes, Justin, “Incompatibilist (Nondeterministic)
Theories of Free Will”, The Stanford Encyclopedia of Philosophy (Spring
2013 Edition), Edward N. Zalta (ed.), URL = <http://plato.stanford.edu/archives/spr2013/entries/incompatibilism-theories/>.
Dennett, Daniel. 2003 Freedom Evolves. London, Penguin.
Iredale, Matthew 2012 The Problem of Free Will. Durham, Acumen.
McKenna, Michael, ‘Compatibilism’, The Stanford Encyclopedia of Philosophy
(Winter 2009 Edition), Edward N. Zalta (ed.), URL = <http://plato.stanford.edu/archives/win2009/entries/compatibilism/>.
Nichols, S. & Knobe, 2007 ‘Moral Responsibility and Determinism: The
Cognitive Science of Folk Intuitions. Nous 41(4):663-85 in Iredale, Matthew
2012 The Problem of Free Will. Durham, Acumen.
Taylor, Richard. (1976) ‘Freedom, Determinism and Fate’; printed in Time,
Self and Mind Study Guide, Monash, 2012:40-47.
van Inwagen, Peter (2009). The Powers of Rational Beings: Freedom of the
Will. Oxford.
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发帖数: 8336 | 3
【在 n********n 的大作中提到】
: Determinism, free will and compatibilism
: by Tim Harding
: The idea that the future is already determined is known in philosophy as
: determinism. There are various definitions of determinism available; but in
: this essay, I shall use the Stanford Encyclopedia of Philosophy definition,
: which is ‘the metaphysical thesis that the facts of the past, in
: conjunction with the laws of nature, entail every truth about the future’ (
: McKenna, 2009:1.3).
: This idea presents a difficult problem for the concept of free will: how can
: we make free choices if all our actions are determined by the facts of the
| P******l
发帖数: 1648 | | n********n
发帖数: 8336 | |
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