Realism
realist
The view that something exists independently of our minds, beliefs or language — used of the external world, of universals, of moral facts and of scientific entities, with a different dispute in each case.
In practice
Asking whether a metric measures something real or is an artifact of how it is collected is a realism question, and the answer changes what decisions it can support.
The common mistake
Treating realism as one position. Someone can be a realist about physical objects and an anti-realist about morality without inconsistency, because the disputes are independent.
Realism is a family of positions rather than one, and the word is nearly useless without saying what it is realism about. Each version claims that some class of things exists independently of what anyone thinks.
The main disputes
About the external world. That physical objects exist whether or not they are perceived. The opposing view is idealism, and Moore's reply was that the claim is more certain than any premise an argument against it could use.
About universals. That properties exist over and above the things having them. Plato placed them in a separate realm; Aristotle placed them in particulars. The opposition is nominalism.
About morality. That moral claims state facts which hold independently of anyone's attitudes. The opposition includes expressivism, which treats moral statements as expressing attitudes, and moral relativism.
About science. That well-confirmed theories are approximately true and their unobservable entities exist. Anti-realists hold that theories are instruments for prediction, and whether electrons exist is a question the theory does not require you to answer.
The two standard arguments
No miracles. Scientific realists argue that the success of science would be miraculous if its theories were not approximately true. Predicting something novel and precise is hard to explain by luck.
Pessimistic induction. Anti-realists reply that the history of science is full of successful theories whose central entities do not exist — phlogiston, caloric, the ether. If past success did not track truth, present success is weak evidence too. See scientific method and paradigm shift.
Why the label misleads
Someone can be a realist about the external world and an anti-realist about morals, or a scientific realist and a nominalist about universals. The positions are independent, and treating realism as a single temperament is the most common error made with the term.
Concept web
Open the full webQuestions
What is realism in philosophy?
The view that some class of things exists independently of minds or language. It is a family of positions — about the external world, universals, morality and scientific entities — and each is a separate dispute.
What is scientific realism?
The view that well-confirmed theories are approximately true and their unobservable entities really exist, against the anti-realist view that theories are instruments for prediction.
What is the pessimistic induction?
The argument that the history of science is full of successful theories whose entities do not exist, so present success is weak evidence that current theories are true.