This is a question you should have convincingly asked for real at least once in your life. The Matrix and Descartes have told us it is very possible it is not real – and like Cypher in the Matrix, maybe this world is better than the one you would wake-up to, so maybe it’s best not knowing. Luckily it doesn’t need an answer – for the very reason that it might not be something that is actually provable from inside it. So either this is real, it is unknowable that it is not real, or we do prove it’s not real and may not like what we reveal.
The important lesson from Descartes for science is not whether you are real, but the vital humility we must operate with in our thinking: we must start all knowledge by fully acknowledging that we know nothing – nothing – as being 100% ironclad ‘true’. *
Starting with that, we can only make ‘reasonable assumptions’ (and that’s using reasoning equipment and rules that we have just admitted might be flawed). This is where Math and probability help out. We can’t know if this is real, but we can assume it is real. Why? Well, because, up to this point, no human ever has convincingly shown it to be otherwise. This does not mean that if everyone thinks something, it must be correct (we know that’s not true). But it does seem to put the odds very heavily in favor of: it is real, it is unknowable by humans if it is not real or we are very far from the point we can finally prove it and stop the lie). And all of these scenarios end in the same mandate: operate as if this is real and matters – in case it does.
So, we get our first mission: go ahead and pretend the world is real, and that it matters somehow – but with the utter humility that maybe it’s not real, and that would be really interesting to find out if someone could prove it one day.
From there we just believe things more and more based on Reasoninng. Reasoning come in two basic flavors Inductive and Deductive. Basically you believe something because you studied/tested the idea and the results seem pretty strong, or you belive it because someone else said it, and that source seemed reliable enough to just accept it. Deductive might sound really lazy, but it’s indispensible – not one has the time to test everything for themselves to decide if it is correct or not – at some point you have to trust what others say.
The problem here has become highlighted with the advent of the internet: is your source reliable? This is where Science comes in. It is a system built around a foundation for coming up with ideas that you can trust – not because of the source, but because of the system. Yes, Aristotle began us down a path toward the Scientific, and most people have had to do a lab report: Hypothesis, test Hypothesis, analyze results, decide if Hypothesis was correct (and then re-test – however many times you to need to be confident it wasn’t a fluke). The part of the process that most people leave out is probably the most valuable: peer review. This is a competitive world of ‘coming up with awesome idea ___ first’ on the line. No one is going o let someone claim a discovery if they can prove that it’s wrong, or better can show a mistake they made, but how they ‘saved’ the idea. This, any well-circulated scientific idea that has gained the acknowledgment of most of Science, is probably pretty reliably accurate (for now).
(*Descartes fans may invoke Cogito Ergo Sum, saying, ‘we think, therefore we must exist, in some form, to be doing the thinking – so we do know one thing: that we do not not exist.’ I like it, but many philosophers and quantum physicists have happily spent their lives trying to make even that seem uncertain.)