[ Nancy Cartwright (1999), The Dappled World (Cambridge University Press), pp. 1-19. ]
p. 1 #1
This book supposes that we live in a dappled world.
The laws that describe this world are a patchwork, not a pyramid.
p. 1 #2
Cartwright focuses on physics and economics,
for these are both disciplines with imperialist tendencies.
: they aspire to account for almost everything,
the first in the natural world, the second in the social world.
p. 2 #1
Cartwright's belief in the dappled world is based on the failures
of these two disciplines to succeed in these aspiration.
p. 2 #2
The conventional story of scientific progress tell us
that quantum physics has replaced classical physics.
But quantum physics has in no way replaced classical physics.
We use both.
Quantum physics works in only very specific kinds of situation;
and it has never performed at all well where classical physics works best.
p. 2 #3
This is how Cartwright comes to believe in the patchwork of law.
p. 3 #1
Carl Menger thought that economics works in the same way.
In mechanics we do get exact deductive relations,
but at the cost of introducing abstract concepts like force,
concepts whose relation to the world must be mediated by more concrete ones.
It also means that it is severely limited in its range of application.
Menger said
we can have concepts with exact deductive relations among them
but those concept will not be one that readily represent arrangement
found in ‘full empirical reality’.
p. 3 #2
Economics and physics are both limited in where they govern,
though the limitation have different origins.
Contemporary economics uses
not abstract or theoretical or newly invented concepts,
but rather very mundane concepts
that are unmediated in their attachment to full empirical reality.
Nevertheless we want our treatments to be rigorous
and our conclusion to follow deductively
and the way we get deductivity to put enough of the right kind of structure into the model.
p. 4 #1
Theories in physics and economics get into similar situations
but by adopting opposite strategies.
In the case of physics,
abstract concepts have considerable deductive power
but whose application is limited by the range of the concrete model
that tie its abstract concepts to the world.
In economics, the concepts have a wide range of application
but we can get deductive result only by locating them in special models.
p. 4 #2
Cartwright depends three thesis in this book:
(1) The laws of physics apply only where its models fit,
and that includes only a very limited range of circumstances.
Economics is confined to those very special situations
that its model can represent.
(2) Laws hold only ceteris paribus.
Laws hold as a consequence of the repeated, successful operation
of a nomological machine.
(3) Our most wide-ranging scientific knowledge is not knowledge of laws
but knowledge of natures of things.
The knowledge allows us to build new nomoloigcal machines.
p. 5 #2
The hero behind this book is Otto Neurath.
p. 6 #1
Neurath worked hard to get us to give up our belief in the system.
Neurath taught: 'The' system is the great scientific lie.
과학의 통일에 관한 비엔나 학파의 표준적인 교의
: 각 과학 영역의 법칙과 개념은 더 근본적인 영역의 법칙과 개념으로 환원될 수 있음.
Neurath's picture
: the sciences are each tied, both in application and confirmation,
to the same material world;
their language is the shared language of space-time events,
but beyond that there is no system, no fixed relations among them.
There boundaries are flexible. There is no universal cover of laws.
p. 7 #1
Consider theories in physics or theories in economics.
They are unambiguous; they are precise; they are non-modal;
they have exact relations among themselves. generally expressed
in equations or with a probability measure.('closure')
p. 7 #2
What kind of closure do the concepts of our best theories in physics
have?
The kind of closure is of a narrowly restricted kind:
so long as no factors relevant to the effect in question operate
except one that can be represented by the concepts of the theory.
What kinds of factors can be represented by the concepts of the theory?
We must look to see what kinds of models our theories have
and how they function.
Cartwright concludes that even our best theories are severely limited
in their scope.
That is why physics is a tool of limited utility.
p. 9 #1
Cartwright does not go into what the 'something right' could be.
Rather she want to consider what image of the material world is most consist with our experiences of it.
p. 9 #2
How do we use theory to understand and manipulate real concrete things?
The core idea of all standard answers is the deductive-nomological
account.
But treatments of real systems are not deductive.
This is true even if we tailor our system as much as possible
to fit our theories.
That is, it is not true even in the laboratory.
p. 10 #1
Cartwright's thesis (1) teaches that these deductive account will work only
in very special circumstances,
circumstances that fit the models of the theory in just the right way.
Thesis (2) and (3) imply that to cash out the ceteris paribus conditions of the laws, the deductions will need premises whose language lies
outside the given story.
p. 10 #2
Realists tend toward universal order, insisting not only that the laws of our best sciences are true or are approaching true
but also that they are 'few in number', 'simple' and 'all-embracing'.
Realist-physicist Philip Allport points out,
'a far cry from establishing that such a realist account is impossible'.
p. 10 #3
Cartwright's answer to object was already given by David Hume.
Demea supposes 'the present evil of phenomena are rectified in other regions, and at some future period of existence.'
Philo replies:
p. 13 #2
Hausman notice that economist studying equilibrium theory make serious efforts to improve techniques for gathering and analysing market data,
but they do not generally seek or take seriously other form of data,
particularly data that might be supplied from psychology experiments.
Hausman's account of why:
Many economist believe that equilibrium theory provides
a complete theory of the whole economic domain.
But equilibrium economists show their commitment to this implausible view
when they reject as ad hoc any behavioural generalizations
about individual.
For example, Keynes offered the generalization
that the marginal propensity to consume out of additional income is less than one.
This psychological generalization is consistent with equilibrium theory,
but it does not follow from equilibrium theory.
Instead, it purports to identify an additional important causal factor.
Many equilibrium theorists have rejected it as ad hoc.
If those theorists believed
that economists need to uncover additional causal factor,
then they would not reject attempts to do so.
p. 18 #1
p. 18 #2
Cartwright's research is concerned with how to get the most out of our scientific knowledge as a whole.
(2015.08.21.)
