Hacking’s definition of Scientific-realism and anti-realism
“Scientific realism says that the entities, states and processes described by theories really do exist. Protons, photons, fields of force, and black holes are as real as toe-nails, turbines, eddies in a stream, and volcanoes. The weak interactions of small particle physics are as real as falling in love. Theories about the structure of molecules that carry genetic codes are either true or false, and a genuinely correct theory would be a true one.” - p. 21
“Anti-realism says the opposite: there are no such things as electrons. Certainly there are phenomena of electricity and of inheritance but we construct theories about tiny states, processes and entities only in order to predict and produce events that interest us. The electrons are fictions. Theories about them are tools for thinking. Theories are adequate or useful or warranted or applicable, but no matter how much we admire the speculative and technological triumphs of natural science, we should not regard even its most telling theories as true.” p. 21
Hacking outlines two types of realism:
- Realism about entities = theoretical entities do exist. Anti-realism about entities instead says that they are fictions, logical constructions or parts of an intellectual instrument for reasoning about the world.
- Realism about theories = scientific theories are either true or false independent of what we know and science at least aims at the truth of how the world is. Anti-realism about theories says that theories are at best warranted, adequate, good to work on, etc.
“Anti-realism of entities denies that … less dogmatically, it may say that we have not and cannot have any reason to suppose they are not fictions. They may exist, but we need not assume that in order to understand the world” p. 27
ingredients of scientific realism
Hacking gives W. Newton-Smith’s ingredients of scientific realism:
- An ontological ingredient: scientific theories are either true or false, and that which a given theory is, is in virtue of how the world is.
- A causal ingredient: if a theory is true, the theoretical terms of the theory denote theoretical entities which are causally responsible for the observable phenomena.
- An epistemological ingredient: we can have warranted belief in theories or in entities (at least in principle).
Based on this, Hacking says there is two kinds of scientific-anti-realism:
- instrumentalism rejects claim (1) and says that theories should not be taken literally and are merely intellectual tools for predicting phenomena
- constructive-empiricism rejects claim (3). According to Hacking, the view takes theories to be taken literally and are either true or false depending ont h world but we have no need to believe any theories about unobservables in order to make sense of science.
”if you can spray them, then they are real”
“What convinced me of realism … was the fact that by now there are standard emitters with which we can spray positrons and electrons— and that is precisely what we do with them. We understand the effects, we understand the causes, and we use these to find out something else.” (Representing and Intervening, p. 24)
“Most of today’s debate about scientific realism is couched in terms of theory, representation, and truth. The discussions are illuminating but not decisive. This is partly because they are so infected with intractable metaphysics. I suspect there can be no final argument for or against realism at the level of representation. When we turn from representation to intervention, to spraying niobium balls with positrons, anti-realism has less of a grip. In what follows I start with a somewhat old-fashioned concern with realism about entities. … The final arbiter in philosophy is not how we think but what we do.” (p. 31)
Evaluating Hacking’s argument for scientific realism
| For | Against |
|---|---|
| we have no questions about whether the sprayed oil droplets (and their properties like weight) as real or not, and should have some standard for electrons | this is still indirect evidence that there really are electrons. In a sense, it is good evidence for the predictive power of the model, not that electrons are actually out there |