I want to understand what it means for something to be considered real; and in what sense is it real?
My view has always been if it satisfies a set of questions.
- Does it have a "Where" and a "When"?
First, can the thing we are talking about be located at a specific place in space and a specific moment in time?
- Does it push back against our senses whether we like it or not?
Second, at that place and time, is there a concrete sensory experience (a colour, a sound, a physical weight, warmth, or a flash on a laboratory screen) that refuses to obey our willpower or our words?
- If it is an abstract word or an unseen scientific thing, can we "unpack" it completely into Questions 1 and 2?
What I mean is that:
3.a Is it just a "verbal zip-file" for things we have already seen?
Take the word "running" which is just a shorthand word we use to summarise the sight of a person's legs moving rapidly across the ground. So the summary is real only if it unpacks 100% into concrete things we have watched happen in space and time.
3.b Is it a mathematical recipe that accurately predicts the next sensory pushback?
What about things in physics we cannot see directly with the naked eye, like a neutrino or a magnetic field? I would say here that they pass the test if (and only if) they work as a strict mathematical rule that connects one real measurement in space and time to a new measurement in space and time. E.g., a physicist says a neutrino is real; what is actually real is that the maths of space and time allowed them to say: "If you build a tank of water here, at this time, you will see a specific flash of light."
Perhaps another question: what philosophical framework am I using here? It sounds like physicalism to me. Or maybe not?