http://en.wikipedia....t_(philosopher)http://www.isnature...._Laws_draft.pdfhttp://www.smu.edu/N...ght-04april2012Although philosophers generally believe in laws and deny causes, explanatory practice in physics is just the reverse. Page 1
No God, No LawsNancy Cartwright
Philosophy
LSE and UCSD
Introduction. My thesis is summarized in my title, ‘No
God, No Laws’: the concept of a law of Nature cannot be
made sense of without God. It is not as dramatic a thesis as
it might look, however. I do not mean to argue that the
enterprise of modern science cannot be made sense of
without God. Rather, if you want to make sense of it you
had better not think of science as discovering laws of
Nature, for there cannot be any of these without God. That
depends of course on what we mean by ‘laws of Nature’.
Whatever else we mean, I take it that this much is essential:
Laws of Nature are prescriptive, not merely descriptive,
and – even stronger – they are supposed to be responsible
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for what occurs in Nature. Since at least the Scientific
Revolution they are also supposed to be visible in the Book
of Nature, not writ only on stone tablets nor in the thought
of God.
My claim here is that neither of these features can be made
sense of without God; this despite the fact that they are
generally thought to provide some autonomy of the world
order from God. I will focus on recent accounts of laws of
Nature and describe how the dominant ones fail without the
efforts of God; I shall also outline one alternative that tries
to make sense of the order of Nature and the successes of
modern science without laws of Nature and without
immediate reliance on God.
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Empiricism. The most dominant view of laws of Nature in
contemporary Anglophone philosophy of science is
empiricism, which takes its starting position from David
Hume. Empiricists suppose that there is no such thing as
necessity in the empirical world, apart from logical
necessity. Nothing in the empirical world makes anything
happen. Nature is just a collection of events, one after
another.
There are, as it turns out, regular associations among these
events – the force experienced by an object is regularly
equal to its mass times its acceleration; these are the facts
recorded in what we call ‘laws’ in science. This doctrine
can thus provide a sense to the idea that laws are writ in the
Book of Nature: laws are regularities that occur in Nature.
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The problem, I shall point out, is that there is no way in
which these laws can be said to govern events in Nature.
There are three decreasingly strict versions of the empiricist
approach to laws of Nature:
1. egalitarian empiricism: all regularities are equal.
2. class-ordered empiricism: some regularities have a
higher status than others; these we call ‘laws’. What
makes for high status in a regularity? There are two
chief candidates on offer. The first is that high-status
regularities should have universal scope: f=ma
universally whereas All the coins in my pocket are
British has a very narrow scope. The second, which is
very popular, is that the high-status regularities are
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those that simultaneously maximize simplicity of
expression with breadth of coverage.
3. blue-blood empiricism: it is not just that some
regularities have more of something – like breadth of
scope or simplicity; some are qualitatively better in
that they hold necessarily. How can such a view label
itself ‘empiricist’? You will understand one reason for
this when see we how much more radically
unempiricist the next alternative is. A second reason is
in the kinds of accounts of necessity on offer. What
seems to be important for empiricists of this stripe is
to avoid the idea that anything in Nature makes
anything else happen; Hume after all taught that we
find no such thing in our experience of the world. The
favoured account is that necessary regularities are
those that not only hold, but would continue to hold
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were their antecedents brought about in arbitrary
ways.(So, ‘All the coins in my pocket are British’ does
not hold necessarily. If I were to put the coins in my
pocket that I got in change from my gelato, the
regularity would break down.)
I think that this last view cannot be carried off. There is
no fact of the matter about what would happen if this
heavy body were released without further non-Humean
facts like the earth has the power to make heavy bodies
fall. That, however, is not the primary objection of
relevance here. What matters for my arguments about
God and the laws of |Nature is that the laws we get even
from blue-blood empiricism cannot govern.
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What after all is a law on this view? It is a regularity,
albeit a very special kind of regularity. And a regularity
is just a collection of paired events: B follows A once, B
follows A again, it does so again, and again and … It
doesn’t matter in what mode the regularity occurs,
whether for instance this kind of pattern would continue
to obtain if A were to occur in different circumstances or
in different possible worlds. A regularity is just a
collection of paired events and a collection does not
make any of its members happen. This would still be true
even if we could find some stronger sense of necessary
to characterize the special collections we call ‘laws’. So
long as laws are collections of happenings, there is no
sense in which they can be taken to be responsible for
what happens.
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In a sense empiricists admit this. Their project has not
been to salvage laws but rather to salvage empiricism in
the face of the structure of modern science. Clearly some
things are privileged by modern science: the equations of
quantum field theory or of the general theory of
relativity. Empiricists have to make sense of this given
their view that Nature is just made up of one event
succeeding another, succeeding another, … Their view is
tailored to achieve this: the ‘laws’ and equations of
science refer to regularities and the regularities that get
represented as laws are the high-class ones, by whatever
the favoured criterion for class is.
What you cannot do on any of these empiricist accounts
is to find something in the empirical world that governs,
i.e. a law of nature. To that extent these three accounts
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are self-consistent: empiricism rejects governance as a
feature of the empirical world and governance does not
sneak in the back door in the reconstruction of laws as
classy or blue-blood regularities.
This does not, though, make these empiricisms
inconsistent with governance, tout court. In its origins in
the Scientific Revolution modern empiricism was neither
conceived nor intended to be at odds with governance.
Laws were God’s plans: the blueprints according to
which God makes things happen. They are visible in the
Book of Nature in the way in which an architect’s plan is
visible in the finished building or the laws of a good
society are visible in its functioning. Without God,
however, God’s plans and God’s will, there can be no
laws of Nature for an empiricist. There is no other
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account on offer that provides empiricist science with
laws of Nature.
Platonism. The second most dominant view of laws of
Nature in contemporary Anglophone philosophy is
Platonism. Platonists believe in abstract entities, for
instance mathematical objects (like numbers) or
properties or quantities. Versions of Platonism differ
according to whether all these abstract entities have to
appear in concrete objects and events or not. Laws of
Nature are relations among abstract entities like the
quantity force, the quantity mass and the quantity
acceleration. This contrasts with the regularity account,
which looks for laws in relations not among the abstract
entities but among the concrete events in Nature in
which these abstract entities participate.
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Platonisits’ laws are necessary because it is part of the
essence of the abstract entities that they relate in the
specified way: if they did not, they would not be the
abstract entities that they are. This solves the blue-blood
problem for regularities. ‘F=ma’ is a blue-blood
regularity appropriate to figure in science because the
abstract quantities force, mass and acceleration must
relate in the way we record in ‘f=ma’, otherwise they
would not be the very quantities they are. All the coins
in my pocket is not because being British is no part of
the essence of the abstract property composed of being a
coin and being in my pocket.
Suppose we accept all this. It still does not provide us
with laws of Nature. The best it does is to solve the
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problem the empiricists aimed to solve: to explain why
some regularities are better than others. The high-class
ones, the scientific ones, are the ones whose properties
(recall, properties as abstract entities) are related to one
another. But how do these relations among abstract
entities govern events in the empirical world?
The idea seems to be that if abstract properties bear a
certain second-level abstract relation to each other in the
Platonic realm, then the systems that instantiate those
properties will be related in some ‘corresponding’ way1
in the empirical world. But what makes that true? We
could say, “That is just what we mean by claiming that
the corresponding properties are related.”
1 That is, they will be related in some way that corresponds to the second-level abstract relation.
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The problem is that we cannot just say this. We have
already fixed what we mean by saying that the properties
relate in that way: it is part of the essence of the
properties that they do so. And we did this for good
reason: to solve the blue-blood problem. Now we need
some account of why when abstract properties relate in
the way they must given what they are, the systems that
instantiate them relate in some corresponding way. In
fact we need more than that. For we not only want the
relations in the empirical world to hold whenever the
abstract ones do; we also want the fact that the abstract
relations hold to be what makes the empirical relations
hold. That story is lacking.2
2 I think this point is similar to that made by Bas Van Fraassen in 'Laws and Symmetry', that accounts of
laws of nature must overcome two problems, the problem of inference and the problem of identification.
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Worse, I don’t think there is any story that can be told.
Abstract relations are not the kinds of things that can
make other things happen; they are not the kinds of
things that have powers. There is nothing internal to the
relations themselves that can do the job. If these Platonic
relations are to figure in an account of what makes things
happen in the empirical world, some outside force is
required to make them relevant. They may serve as
God’s blueprints for what he brings about in the world,
but they cannot bring about things themselves. What
Platonists call ‘laws’ as well as what empiricists call
‘laws’ need God and his direct control of the world if
these are to be laws at all.
Instrumentalism. Instrumentalists give up on laws of
Nature altogether. The ‘laws’ and equations of science
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are considered as instruments or tools for making very
precise predictions, for building things, for making new
discoveries. These ‘laws’ need not fit together in any tidy
way. They can be at different ‘levels’ of description, use
different mathematics and different concepts, cover
different kinds of things and even leave a lot uncovered.
I like instrumentalism because of the second feature of
laws which we have not focussed on yet: laws are to be
visible in the Book of Nature. The usual meaning of this
is that the laws are reflected in the regularities of Nature.
But I am sceptical that the right kinds of regularities are
there. We certainly do not see them. Most of our ‘laws’
have sweeping exceptions; we could not even hope to
see them obtain except in very special circumstances –
mostly inside the laboratory or in some specially
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felicitous natural arrangements like the planetary
systems.
Often we are told that despite appearances the
regularities really do obtain. Where? “Behind” the
phenomena, or perhaps “inside”. But these are
metaphors. There isn’t any front and behind to the
phenomena, any surfaces and insides. Things in the
empirical world do have components. Because of our
failure to make sense of regularities holding ‘behind’ the
phenomena we have been driven to rely on the notion of
components.
Large things may not behave in properly regular ways,
but their components do…or the components of the
components, or… In the end at last we reach the
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fundamental particles. These do behave regularly – or so
we say. In the end the only genuine laws of Nature then
are the laws of the physics of fundamental particles. I
am suspicious of all this. Why are these very central
regularities all just where we cannot see them? By
contrast, the one regularity I am really sure of is highly
visible: All men are mortal.
These questions about the scope of the regularities of
contemporary physics are a central concern of mine. Let
me summarize one main line of thought. Physics is dense
and highly interconnected; there’s nothing you can say
that doesn’t have countless implications that themselves
have implications, and so on. This is to a good extent
why physics is so powerful. If you find out just the right
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kind of information for your problem, that can have an
amazing rich set of precise consequences.
The drawback is that this thick set of interconnections
places enormously strict constraints on when any
particular physics concept can apply. This can very much
narrow the scope of where these concepts do apply – and
I think it does so. Not a whole lot of the world can satisfy
these constraints. We have good evidence, for instance,
that quantum constraints are satisfied in the material
structure of superconductors, but little evidence that they
can be satisfied for other kinds of macro-systems. As the
Nobel prize-winning quantum physicist Willis Lamb has
told us in lectures at LSE, it is very hard to get a system
into a quantum state.
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Those who believe in the universal scope of these laws
have a familiar reply. What Lamb is talking about is the
difficulty of getting a system into a known quantum
state. All systems are always in quantum states – we just
can’t ascertain them. Again, I am suspicious. I have
positive evidence that a variety of kinds of systems can
satisfy the constraints; I will await positive evidence
before I believe the others can.
To return to laws of Nature. Despite the fact that
instrumentalism eschews laws, I think it provides the
best fit between God and the laws of Nature. Suppose we
admit God into either the empiricist or Platonist frame, in
order to show how the laws can govern. We still wish to
see that these laws are writ in the Book of nature.
Regularities are essential to both the Platonist and the
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empiricist account here. For the empiricist, laws are
visible in Nature since laws just are regularities in
Nature. For the Platonist, although the laws are in the
Platonic realm, they are “mirrored” in Nature, again in
Nature’s regularities. The whole picture does not work if
these vaunted regularities are not there after all.
Instrumentalism offers an alternative. God uses the
‘laws’ of science in making things happen in the world in
much the same way that we do, as an instrument for
calculating what is to happen. The laws are indeed writ
in Nature but not in the questionable regularities of the
empiricist or Platonist account. They are writ rather in
the more complex, untidy particulars of everything that
does in fact happen.
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Aristotleanism. The last of the contemporary views about
laws finds its source in Aristotle. Like instrumentalism, it
does not suppose that there are laws of Nature. The laws
of science describe the powers that systems in Nature
have by virtue of certain facts about them.3 For instance,
material systems, by virtue of having gravitational mass,
have the power to attract any other system that has mass.
This kind of view has long been out of fashion,
especially among empiricists who take their cue from
Hume and who altogether reject talk of powers, causings,
makings and necessity in the empirical world. But it has
not always been so with empiricists. Early British
empiricists – before the spread of the Cartesian doctrine
of ideas and long before Hume – were committed to
3 For Aristotle, by virtue of their “Natures”.
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basing science on what is given in experience. But this
does not rule out powers, though it does make talk of
them difficult for post-Lapsarian man. For instance
Joseph Glanvill, apologist for the Mechanical
Philosophy, tells us that Adam could see the exercise of
powers: “…the influence of the Moon upon the Tides
was no question in his Philosophy.”
I endorse this kind of pre-Cartesisn/pre-Humean
empiricism and I have spent a lot of effort trying to show
that notions like powers and causings are not only
compatible with an empiricist view of science but that
we cannot make sense of science without them. This is a
long story. The one thing I should note here is that in the
right circumstances powers can play themselves out in
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regularities. But when the circumstances are not
felicitous what happens may be highly variable.
With respect to our central issue my major claim about
Aristotleanism then is this: Aristotleanism rejects laws of
Nature. But (if I and other recent advocates of powers in
science are right in our claims about them) it can make
sense of the laws of science in a way that respects the
two requirements we placed on laws of nature
(governance and visibily in Nature itself) and it can do so
without God. On the Aristotle-inspired account, there is
necessity and governance in Nature: natural systems
have powers and events in Nature are made to occur in
the way that they do by the exercise of these powers. The
laws of science describe these powers. As in the case of
instrumentalism, the results predicted from the laws of
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science are indeed visible in Nature and without the need
for hidden and secret regularities.
Conclusion. None of the 4 contemporary accounts of
laws that I have reported on can make sense of laws of
Nature without God. The last, Aristotleanism, can offer a
stand-in for laws – natural powers – that satisfies the
major requirements on laws without the need to call on
God.4 For those who cannot abide powers, I think there
are no options left. Without God there cannot be laws of
Nature, nor anything else with their crucial
characteristics
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