Twentieth Century Thinking
about Science
Revolutions and Progress
Three Developments
• Quantum physics: A radical break with classical
mechanics, driven by the failure of late-19th century
physicists to successfully link thermodynamics and
electrodynamics (the problem of black-body radiation).
• Relativity: A conceptual revolution within classical
mechanics, driven by a fundamental tension between
electrodynamics and mechanics.
• Formal first-order logic: A powerful language in which
to represent arguments, theories and relations
between concepts. It was hoped that this new tool
would allow us to clarify and even resolve many
philosophical problems.
Upshot
• Philosophical ideas about science were greatly
changed: Kant had proposed that classical
mechanics was the result of fundamental rules
governing how we construct our representations
of the physical world. Many others had been
convinced that we were very close to finalizing a
complete understanding of basic physics. A new
account of the nature of science was needed.
• Philosophers using the new tools of formal logic
hoped to understand the workings of science and
to interpret/ explain the new ideas.
Philosophy’s influence
• Philosophical questions can often seem abstruse,
remote from real life, and downright pointless– a
standard example: how many angels can dance
on the head of a pin (originally, the point of a
needle)?
• It turns out that this may have been a later
satirical jibe at medieval ‘angelology’, but even
so, there’s a fair question here about entities that
have no spatial extension and whether an infinite
number of them could or could not ‘add up’ to
occupy some finite size.
The Science Wars
• In the late 20th century, some academics &
intellectuals declared that developments in the
history, sociology, anthropology and philosophy
of science had shown that the general acceptance
of science as authoritative on its subject matter
was unjustified.
• This is clearly a matter of some importance– it
affects how we should respond to scientific
claims about the threat of global warming, along
with many other issues and problems.
Real examples
• But the influence of philosophy has often been
quite substantial.
• Mach’s radical phenomenalist ideas about
observation and theory influenced Einstein.
• Ideas about observation and evidence had a
major influence on 20th century psychology.
• Darwin’s argument for evolution by natural
selection, in The Origin of Species, was influenced
by 19th century philosophy of science (Herschel &
Whewell) & the idea of a ‘vera causa’.
What is science?
• We may often know it when we see it, but that doesn’t answer the
question in a helpful way.
• There are important disputes here: Is science a method that individuals
can use to acquire knowledge, or is it intrinsically social? Is it something
practiced, if differently, in all cultures? Or is it something specific to a
particular culture (which has since spread to many others)? Is economics a
science because of its use of mathematics? Or are its predictive
limitations reason to regard it as something less than a proper science?
Does a science get to be a science because of its record of success, or
because of how it tries to answer questions? What counts as success?
What is a scientific approach to answering questions?
• Central examples are still a good place to start: physics and chemistry are
standard examples of what’s often called natural science; geology and
paleontology are standard examples of historical sciences; finally, we
sometimes recognize (with varying degrees of condescension) social
sciences including sociology and anthropology.
Two Questions
• Godfrey-Smith proposes two questions for us:
– How do people, in general, acquire knowledge of the world around
them? (This is a question about science in the broad sense.)
– What (if anything) is special about the scientific tradition that emerged
in western Europe during what we call the ‘scientific revolution’? (This
question focuses on science in the narrow sense.)
• The first is a central problem in epistemology– and (for all its
obviousness in common-sense terms) a very difficult one to sort
out.
• The second raises a very complex set of issues including questions
about social history, the combination of mathematics with
experimentation and observation, and the idea of just what a
‘scientific theory’ is…
Knowledge in general
• There are very tough philosophical puzzles here. When we
claim to know something, people often ask for evidence/
support for what we claim to know.
• This support takes the form of further claims from which
the claim being defended can (it is claimed) be inferred.
• But it’s hard to see how we can convince any sort of
skeptic this way: The skeptic can always question either the
new claims, or the inference from those claims to the initial
knowledge claim.
• This creates a (double) regress in the structure of
justification: To justify p, we claim both that q and that p
can be (correctly) inferred from q. So there are two ways to
question any justification.
Blocking the regress?
• One way to block this sort of regress is to identify
a collection of claims and a collection of
inferences that are not subject to question.
• Then the rest of our knowledge claims will turn
out to be justified if they can ultimately be traced
back to this foundation.
• Many early modern philosophers (especially the
empiricists) thought of our knowledge of our own
ideas as the special, unquestionably correct
claims on which all knowledge of matters-of-fact
are based.
Troubles
• Getting out from behind the ‘veil of ideas’ was a tough
challenge.
• Is there some kind of unquestionable inference that can
reach conclusions about the public world from premises
that are only about the character of our ideas?
• Even if we can arrive at knowledge of the external world
this way, it seems still harder to arrive at any kind of
knowledge of other minds.
• But the special privilege of our knowledge of our ideas
depends on it’s not being subject to any challenge– so the
barrier to knowledge of other minds is part of what ensures
our knowledge of our own minds is unquestionable. This is
a nasty trap.
Coherentism
• A key assumption that makes the regress so
threatening is that justification cannot ‘move in a
circle’: when we justify p, we must always invoke
new claims. No matter how far we trace back our
justification, we can never end up invoking p as
part of the justification.
• Coherentists reject this constraint: for them, the
web of inferential relations linking our claims can
make the entire system justified, even though no
claim can stand on its own.
Troubles again
• The standard objection to this is that nothing
seems to ‘anchor’ a coherent collection of claims- so there’s no reason to suppose a coherent
collection of claims would correspond to the
world. But that’s an important part of many
philosophers’ views on what truth is.
• In general, this standard is met by many different
collections of claims– so how could we choose
the right one? Again, it seems we need some sort
of external standard that coherentism can’t
provide.
A personal remark
• I’m a coherentist– I think that there are good answers
to these challenges (in part, because I’m no fan of
correspondence truth, and in part because coherent
systems of claims can be anchored in a practice of
accepting new claims (a practice whose reliability is
supported by claims we already accept). Finally, I find
foundationalism dubious because I’m a holist about
justification– I think we have to know many things in
order to know anything.
• But many of the philosophers we’ll be reading about
here are foundationalists, as you’ll see.
Issues in philosophy of science
• Epistemic: How are scientific claims justified? This
question is especially hard to answer when we think of
large-scale theories; clearly, their justification draws on
observations we’ve made. But they reach far beyond
any actual observations. So it’s hard to see how any
actual collection of supportive observations could
really justify something like (say) Newton’s universal
gravity or the descent of all life on earth from a
common ancestor. (It’s worth pointing out,
nevertheless, that we often do find the evidence
persuasive.)
• Can we expect science to arrive at the truth?
More issues
• Metaphysical: Do electrons (genes,
phlogiston) really exist? How can/ should we
decide such metaphysical questions?
• Philosophy of Language: How do words and
sentences come to have meaning? What is it,
for a word or sentence to have a meaning?
Reflections on our subject matter
should be
• Scientific thinking? Some have argued that
this is too psychological/ too anthropocentric.
• The logic of (correct) scientific thinking? This
was particularly tempting because of the new
logical tools available & being developed at
the beginning of the 20th century…
• Scientific method (a broader notion than just
the ‘logic’ of science).
Descriptive or Normative
• This is a major divide in approaches:
We can confine ourselves to describing what
science is/ how it’s done/ etc.
Or we can think (as the logicians I described above)
about how science should be done.
Even methodological or logical treatments can be
descriptive (they can describe the actual method
used or the actual logical relations observed
without commenting on what the method or
logic should be).
Why the logic of science?
• The idea was that logic is objective in a very important
sense: It’s universal, applying in all languages and theories,
so it could provide a normative standard for science that
would hold always, independently of the circumstances,
whether social, psychological, historical or personal.
• But the result is somewhat detached from the actual
business of doing science– abstracting from particular
subject matters, the particular problems that are important
in a given subject at a given time, etc.
• Godfrey-Smith proposes instead that we think about a
scientific strategy for investigating the world, and what sort
of results we can expect that strategy to produce. This is
pretty vague– let’s hope the blank check gets covered later
on…
Important points about science
• Empiricism. On this score science outdoes ordinary
knowledge just by being more systematic, organized
and ‘responsive’ to experience.
• Examples in the history of medicine make for good
material here. Semmelweiss and childbed fever; John
Snow and the Broadstreet pump. (But lucky
Pettenkofer shows that common-sense tests aren’t
always enough…)
• This leaves important philosophical puzzles, too: just
how does experience translate into knowledge?
Mathematics
• Galileo declared that the book of the world is
written in the language of mathematics.
• Science has made a lot of progress by applying
mathematics to its descriptions of the world.
• But how does this fit with empiricism
(mathematical knowledge seems to be different
from observational knowledge, but it’s only by
means of observation that we can see if our
mathematical ideas actually apply to the world…)
• But some perfectly good science makes no real
use of mathematics (Darwin).
Social Structure
• There is a lot to be said for the importance of social
structure to the workings of science as we know it– no
single investigator would get very far, and each generation
of scientists builds on the results of previous generations.
Trust and cooperation are indispensable (from that
between researcher & co-workers to entire communities of
researchers who rely on each others’ work and what is
accepted/published in the journals).
• Social institutions (from networks of correspondents to the
Royal Society and its emulators to universities and
publishers and granting agencies...) are all important to
understanding how science as we know it works.
• G-S emphasizes empiricism and social structure in his
account.
Potted history
• This is both critical to presenting philosophy of
science, since credible philosophy of science
really does need to make contact with actual
examples of science, and a real hazard, since
history is so rich and complex that it’s often
possible to tell a conflicting story about the very
same history. We have to be on our guard with
this– and watch carefully what others do when
they make appeals to history– it’s all too easy to
shape it in ways that bias our understanding…
That said…
• The standard examples of the scientific
revolution, from Galileo and Kepler and the
establishment of a sun-centered view of the
solar system to Darwin (later than G-S’s limit
of 1700, I know) are all extremely vivid
examples of successful, systematic scientific
thinking. They really do, I think, justify
curiousity about what (beyond some good
luck) makes this approach to investigating the
world so powerful.
Upshot
• Not only did we learn immense numbers of new things
about the world over this time, we learned how things
fit together: How the motions of the planets fit
together with a history of how solar systems like ours
get formed, how the fossil record fits with the facts of
development and taxonomy, how the physics of local
events fits with (is identical to) the physics of events in
the heavens, how heat is produced and how it flows
from hotter to colder, and how that flow can be tapped
to do work, not to mention how clean water supplies
and garbage removal and vaccinations can improve
health and even eliminate some diseases.