Scientific Realism 7 - Entity Realism

Entity realism, most famously defended by Ian Hacking, is the view that we should believe in the unobservable entities postulated by scientists, but be skeptical of scientific theories. In this video I examine Hacking's "manipulation argument" for entity realism, which claims that we must believe in those unobservable entities that we can use as tools for studying other phenomena.

[@ViniciusRodrigues534]

Just a little corretion: Derek Turner's books is called "Making Prehistory" not "Manipulating Prehistory". Excellent work in making Hacking's entity realism understandable. Love your videos ;)

[@james1098778910]

Regarding the 3rd interpretation of the argument at around 28:00: what's the difference between ' if you heat and then cool a fluid we think contains dna-strangs, primers, the four bases etc i. e. if you use pcr, the result is exactly the one we would expect if our theory were true' and 'pcr works'?

[@Ansatz66]

Before we accept that being able to manipulate a thing makes it real, we really ought to consider what it would look like for someone to manipulate something that is not real. Then we can say that when P thinks he is manipulating X he is just crazy and confidently say that when we think we're manipulating Y we're nothing like P and X. Suppose Paul believes in fairies and his theories about fairies lead to direct evidence that fairies exist. Fairies are tiny unobservable creatures that cause plants to grow in much the same way that construction workers cause buildings to grow. When Paul plants seeds in his garden he does it because he believes the seeds will lure fairies to the soil. When Paul waters his garden he does it because it is necessary to prevent the fairies from becoming dehydrated, and just look what happens when the garden doesn't get enough water. What more proof do you need? Since Paul can tame the fairies and control where they build, they must exist. With the proper application of herbicide Paul can even kill the fairies, and it doesn't just happen in his mind; the plants really do fall apart as a consequence. Can we all agree that fairies don't actually exist and Paul's direct manipulation of fairies cannot serve as justification for believing in fairies? Or shall we be entity realists about fairies?

[@Drakhra]

We could consider here the No-Miracles argument. Though Paul may claim there is no miracle as he postulates the fairy-thesis, we could ask further questions about these fairies (e.g. where do they come from, what do the comprise of, if alive - do they eat? and so on and so on). With the traditional photosynthetic view, deeper questions can be answered with other manipulatable unobservables could be utilised (e.g. these viral phages) to mess with the plants', say mitochondria or chloroplasts. What do you think? Also, I expect in 4 years you may have moved on - so no pressure to reply.

[@Ansatz66]

@@Drakhra : There are always deeper questions that can be asked and there are always limits to what can be answered. What do electrons comprise of? Why do electrons even exist? It's inevitable for science to not have answers to every question, especially the very deepest questions, because science is not magic. The No-Miracles argument is terribly misguided because it assumes that that the success of science can only either come from the reality of scientific ideas or from chance, but really the success of science comes from the hard work of scientists. If Paul spent years in dedicated honest study of plants and came up with an theory of fairies that perfectly explains everything and could be put into useful practice by gardeners, that would not be a miracle; it would be Paul's sweat and tears.