Twentieth Century Thinking about Science

1. Twentieth Century Thinking about Science Revolutions and Progress

2. 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.

3. 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.

4. 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.

5. 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.

6. 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 ‘veracausa’.

7. 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.

8. 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…

9. 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.

10. 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.

11. 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.

12. 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.

13. 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.

14. 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.

15. 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?

16. 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?

17. 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).

18. 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).

19. 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…

20. 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?

21. 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).

22. 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.

23. 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…

24. 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.

25. 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.