Summary: Chapter 15 in What Is This Thing Called Science? / Alan Chalmers
What Is This Thing Called Science? / Alan Chalmers
Chapter 15:Realism and anti- realism
- Realism = science describes not just the observable world but also the world that lies behind the appearances
- Doubts abut realism: extent to which claims about the unobservable world must be hypothetical to the extent that they do transcend what can be firmly established on the basis of observation
Global anti-realism
- We are trapped within language and cannot break out of it to describe reality directly in a way that is independent of our theories
- (Realist) correspondence theory of truth = a sentence is truth if and only if it corresponds to the facts
- Liar paradox: e.g. I never tell the truth
- Tarski: avoid paradoxes by distinguishing the object language (is being talked about) from the meta-language (in which the talking is done)
- A theory is true if the world is as the theory says it is and false otherwise
- Should scientific theories be taken as candidates for truth or as making claims about the observable world only? Neither side supports global anti-realism
Anti-realism
- Instrumentalists: theories are just useful instruments to predict results
- Van Fraassen is not an instrumentalist for theories can be true or false, but the merit is judged in terms of its generality and simplicity and the extent to which it leads to new observations à constructive empiricism
- Motivation of anti-realism = desire to restrict science to those claims that can be justified by scientific means. Evaluate theories solely in terms of their ability to order and predict observable phenomena
- Theories can be discarded when they have outlived their usefulness, and the experimental and observational discoveries to which they have led retained
Objections and anti-realists response
- Distinction between knowledge at the observational level (securely established) and is best seen as an heuristic aid à problem: theory dependence and fallibility of observation and experiment
- Theories that are predictively successful have to be more or less true and not just instruments à response anti-realists: fact that a theory is productive need be no indication that it is true (historical proof)
- Anti-realists insist that theories must be general and unified – embrace a wide range of phenomena
- The unobservable has no place in science or should be treated merely as useful fiction (e.g. atomic theory) à response: only part of science that is subject to confirmation by observation and experiment should be treated as candidates for truth and falsity, but as science progresses and better instruments and experimental techniques are devised à range of claims that can be subject to confirmation is extended
Scientific realism
- Science aims at true statements about what there is in the world and how it behaves at all levels. Science has made progress to this aim
- Impossible to know that current theories are true, but they are truer than earlier theories
- Hacking: pay attention to what can be practically manipulated in science. Entities in science can be shown to be real once they can be manipulated in a controlled way and used to bring about effects in something else
Conjectural realism (Popper)
- Theories of the past have been falsified and replaced by superior theories
- Problem: weakness of its claims. Science aims to achieve truth and there are ways to recognize how it falls short of this aim (there is no truth)
Structural realism
- Middle ground realism and anti-realism: realist in that it attempt to characterizes the structure of reality: more and more capable. Representations are replaced over time
Idealization
- Duhem: theories cannot be taken as literal descriptions of reality because theoretical descriptions are idealized in a way that the world is not
- Theoretical and observational knowledge
additional summaries in philosophy of science
Some books about philosophy of science to consider:
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