One of the most enduring controversies of philosophy revolves around a dichotomy between free will and pre-destination. There's a Kurzgesagt video about this, that takes a position not wildly different from my own, while summarising the main positions.
In one of the controversy's oldest forms, the notion of divine
fore-knowledge (God knows the future) is pitted against our responsibility for
our actions. In this guise, Boëthius (480ish to 524ish AD) gave one of the
most illuminating answers (in The Consolation of Philosophy
, written in
the 520s), which is incidentally the earliest precursor (to my knowledge) to the
notion of time as a fourth dimension: God stands outside time, so percieves the
whole, while we inhabit time. God is eternal
– simultaneously
embracing the whole extent of time – while the universe
is perpetual
, existing in a progression of moments, experiencing each
separately.
Alan Moore, in an interview, takes a contrary reading of the four-dimensional view of the universe, effectively disposing of the need for a God with fore-knowledge by using the four-dimensional universe as that fore-known thing. General relativity conceives of the universe as a smooth four-manifold in which time is a co-ordinate stretching from an initial big bang to either a final big crunch or a perpetual expansion in utter coldness. Moore interprets this as meaning that all future history is determined, making a mockery of our perception of free will. Boëthius (essentially following an argument from Plato and Aristotle) argues that our free will is real in the present despite that. I could argue against Moore's position by noting the non-determinism inherent in quantum mechanics, but Boëthius's argument rejects his conclusion even without that.
These philosophical musings aside, the study of how our brains work has revealed assorted oddities which complicate the idea further; it would appear that after the brain has made its decision, the ego still thinks it is making up its mind, to mention but one. This casts free will as a delusion of the ego; but may equally be read as implying that free will happens at an unconscious level and the ego is merely a puppet which serves to express it.
It should also be noted that, even without quantum mechanics, physics has a degree of indeterminism in it; to be able to predict the future behaviour of the universe, we must know its initial state; any inaccuracy or gaps in our knowledge of the initial state limit the accuracy of our predictions; and small initial errors can rapidly grow to large enough errors that, in effect, the extent of future into which we can predict much at all is limited. Philosophers tend not to be much impressed with this, since they conceive of the exact thing existing regardless of our inability to obtain accurate information about it; but – like many modern physicists – I am skeptical of a notion of existence except insofar as it is accessible to our ability to observe it. While this latter attitude is largely fostered by quantum mechanics, it exists independently: it has its foundation in Poincarré's assertion that any illusion which the universe conspires fully to sustain is real; this he offered in connection with (not quantum mechanics but) the constancy of the speed of light, on which relativity is founded.
I regard this controversy as a false dichotomy. Not only does it demand that we chose between two extreme positions when there are various hybrids we could consider; it also depends on looking at reality from two entirely disparate perspectives in order to claim the existence of a conflict in the first place.
Well, Utarhaptor has a point (and it's not far from Poincarré's), but
I don't even accept that there is a dichotomy. Even in a deterministic
universe ('though I don't accept that we're living in one of those) wherein
there is a definite moment at which everything has
definite state (which
I don't hold to be meaningful without an observer capable of observing that
state), so that the whole history of the whole universe is determined by that
state at that moment, free will
has a rôle – albeit its
rhetorical baggage needs some re-evaluation.
The first thing to notice is that (the illusion of) free will and its
attendant social dynamics are actually crucial parts of the dynamical system
which determines
our actions. It is commonly said (cf. T Rex, above)
that, if we don't have free will, we're not responsible for our actions: but
actually we are, it's just that what we mean by responsible
has to be
re-evaluated when describing the universe in deterministic terms. We understand
our world well enough to see the causal links between our actions, and those of
folk around us, and subsequent events; we can see that some of the things those
around us can do would cause us harm; thus we can see that discouraging them
from doing those things is to our advantage. It does not matter whether our
decision to so discourage them is a matter of free will or our deterministic
response to our circumstances and nature: we employ the means at our disposal to
regulate one another's behaviour. One of the means at our disposal
is setting a good example
– i.e. abiding by the rules we want
others to follow. Another is treating others generously if they abide by those
rules and harshly if they do not. By holding folk responsible for their
actions, we endeavour to modify their behaviour. Even if society is to
blame
for the (say) kleptomania of an individual, it is still reasonable
(and just) to punish that individual for stealing things – because this is
part of the mechanism by which society attempts to remedy the individual's
flaw. There may be better mechanisms, and we might well do better to explore
those than to use punishment; but this is true regardless of
whether society
or the individual is to blame
.
The real issue is what we think we meen by free
and how we understand
the notion of responsibility
(or blame
). Indeed, even the notion
of causality itself takes on a different aspect, in a determinist
universe. When one studies classical (i.e. pre-quantum) physics, the notion
of cause
gets somewhat nebulous: each of the parts of a deterministic
system is simultaneously responding to what the others are doing and causing
effects upon the others. We may say that the varying current in the wires wound
round an electromagnet cause the varying magnetic field; but if that magnetic
field were present, and varying in the way it is, then that would cause a
varying current to flow in the wire (indeed, this is how the output side of a
transformer works). One cannot separate the two processes; they are
inextricably entwined. In a deterministic description of the universe, things
are so busy causing one another that the very notion of causation becomes
nebulous: things happen, and how they happen follows certain patterns (the laws
of physics), but those patterns as indifferent to the notion of causation as
they are blind to the direction of time.
But this brings me to where common understandings of determinism become
inadequate: I say as indifferent
because, in fact, the laws of physics
aren't entirely blind to the direction of time; and from this I shall
draw out a degree to which a deterministic understanding of the universe does
comprehend a notion of causation. Armed with this modified notion
of cause
, I intend to sketch correspondingly modified notions
of free
and responsible
that are appropriate to a determinist
model of reality.
Before I do that, however, I should address one reasonable objection to this
approach: I may fairly be accused of re-defining free
and responsible
so as to pretend to have resolved the issue, without
really having done anything. Such sophistry would indeed by nonsensical; so
attend closely to whether the meanings I give to the terms do match with what
you understand them to mean. The need to re-state their meaning arises from the
collision between our intuitive understanding of the world and that of
determinism. If I and a friend have two maps of one piece of terrain, one of
which uses magnetic North and the other true North, each with its associated
directions, we need to take care when communicating about the terrain they
depict: what I should call due East is subtly off for my friend. The terrain is
the same, and we can discuss it if we are careful about our choice of words, but
we should not expect every word's meaning to carry over simply from one to the
other. Just so, words taken from our intuitive understanding of the world need
some adjustment if they are to be given meaning within a description of the
world that is not quite in harmony with our intuition.
Most of the laws of physics are unchanged under reversal of the direction of
time. Indeed, if we combine time-reversal with replacing each bit of matter by
the correponding anti-mattter, and also reversing a theoretical construct
called parity
, all the laws of modern physics are unchanged –
except for one. That one is peculiarly statistical and remains the subject of
much philosophising, precisely because it is the only thing in the laws of
physics that really cares about
the direction of time, which seems so
evidently important to us. This law is stated in various ways: heat does not,
of its own accord, flow from a warmer body to a cooler; the entropy of a closed
system never decreases (and lots of things the system can do are apt to increase
it). Formally, I want to state this
law as: when you observe as much as you can about a system, the information
content in the system's state's remaining (internal) degrees of freedom (after
you've taken into account how your observed data constrain them) is as little as
it can be.
That may well seem a peculiar law; it talks about the internal state of a system, which is intrinsically a feature of the model we use to describe it, rather than of the system itself – at least, if we follow the hard-line view of most modern physics, following Poincarré's dictum to its logical conclusion and not attributing meaning to things we can't observe. Furthermore, it talks about the information content, relative to what's implied by what we do observe, contained in these seeminly fictitious internal data. In a sense, it's superficially fatuous – if you've observed everything you can, you've surely got all the information you can out of the system, so obviously there must be as little information content remaining as is consistent with physical law. All these peculiarities are implicated in the vast amount of philosophising done about this law; but, for now, I'll leave these things aside.
What matters, for the present discussion, is that this peculiar statistical
law – known, in one guise or another, as the second law of
thermodynamics
– implies that isolated systems intrinsically tend to
become disordered (albeit in a quite technical sense). Systems can become more
ordered if energy flows through them – specifically, if the energy comes
in in some highly ordered form and flows out in some less ordered form
(generally heat), effectively flushing away the surplus disorder that the system
is losing. This is exactly how each living thing manages to maintain the
intricate state of order that keeps it being the thing it is; and it is this
that makes the arrow of time so important to living things. That dynamic is an
essential ingredient in our notion of causation.
There are various ways that high-order energy can flow into a system (e.g. a
living thing), in contrast to the low-order things flowing out. High frequency
light falls on a plant, triggering chemical activity catalyzed by proteins in
the plant's cells, that transforms (to simplify somewhat) carbon dioxide and
water into sugars and oxygen; the cell then loses surplus energy in the form of
infra-red radiation – which is low frequency light
– and by
warming its environment through conduction and convection. The (relatively)
small number of photons of high-frequency light (all going in roughly the same
direction, although this is less relevant) turn into a (relatively) large number
of photons of lower frequency infra-red (in all directions), along with more
agitated movement of the molecules making up the leaf and surrounding air (or
water); the latter is a more disordered form of the energy, meaning its entropy
has increased, making it possible for the cell to get away with taking some of
the energy, as it passes through, for its own use. It uses that to increase the
order of the carbon dioxide and water by turning them into sugars and oxygen,
which are themselves (relatively) ordered forms of energy. When the sun doesn't
shine, the plant can convert them back the other way, increasing disorder once
more and thus being able to extract some of the energy to put it to other
uses. Animals that eat the plant likewise take sugars they've digested from the
plant and oxygen from the air to drive their own complex chemistry; and so on
throughout the food chain.
Written by Eddy.