Realism: physical world exists independently of human thought and perception.

  • Realist hold that the aim of science is to provide a true description of the world.

Idealism: physical world is in some way dependent on the conscious activity of humans.

(both belong to metaphysics)

  • Anti-realists hold that the aim of science is to provide a true description of a certain part of the world - the observable part (can be directly perceived by humans). They claim that unobservable entities are merely convenient fictions, introduced by physics in order to help predict observable phenomena. We cannot actually attain knowledge from the unobservable part of reality.

- Anti-realism is sometimes called instrumentalism because it regards scientific theories as instruments for helping us predict observational phenomena, rather than as attempts to describe the underlying nature of reality.

Realism / anti-realism debate concerns the aim of science, how to best make sense of what scientist say and do.

Realists: we should interpret all scientific theories as attempted descriptions of reality

Anti-realists: this interpretation is inappropriate for theories that talk about unobservable entities and processes.

Two sorts of anti-realism:

  • talk of unobservable entities is not to be understood at all, it's not possible to make meaningful assertions about things that cannot in principle be observed. (first half of 20th century)
  • talk of unobservable entities should be taken at face value: unobservable reality is either true or false, but we are incapable of finding out which. (modern)

Empirically successful: the make excellent predictions about the behaviour of objects in the observable world

‘No miracles' argument: it would be an extraordinary coincidence if a theory that talks about electrons and atoms made accurate predictions about the observable world - unless electrons and atoms actually exist. Do anti-realists believe in miracles? Or can a theory be false and yet empirically successful?

Is it always clear how to distinguish observing from detecting?

Anti-realists emphasize that the ultimate date to which scientific theories are responsible is always observational in character.

According to anti-realists, scientific theories that posit unobservable entities are underdetermined by the observational data - there will always be a number of competing theories that can account for that data equally well.

A general truth: observational data constitute the ultimate evidence for claims about unobservable entities. Underdetermination argument: there are always multiple explanations of our data, we have no way of knowing which is true, so knowledge of unobservable reality cannot be had.

But what about the objects and events that a observable but unobserved?

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