To understand what the core problem of the 20th Century is, we need to understand the foundation upon which it rests. And this article, in the Daily Mirror, of all places, serves well to illustrate the problem.
Elon Musk isn't stupid but even he admits that there is a chance that we could be living in a "simulated" reality. He is indeterminate on the matter because, quite simple, it's impossible to be definitive.
Let me illustrate what I mean. In the movie the Matrix, the "reality" human beings experience is simply a computer program operating though a spinal modem which completely controls their sensory experiences. The famous scene of Neo "unplugging" from the Matrix serves to illustrate the difference between the reality, as experienced through the spinal modem and the "real" reality.
But here is an interesting thought experiment: Suppose you are connected to a spinal modem and disconnected yourself, how could you prove that you were really disconnected? How could you be sure that the act of disconnection was not just another "simulation" designed to lull you into thinking that you were, when you really weren't? Think about if for a while.
The idea of living in a reality that is only just a simulation isn't as far fetched as it sounds once you start thinking about the problem. The real problem is how do you prove the question is not true once it has been asked? The answer is you can't, and it's why Musk doesn't give a definitive yes or no answer to the question. As I say, he's not an idiot. Kurt Godel and Alfred Tarski would both answer along the same lines.
What's all this got to do with 20th Century history? A lot actually.
Prior to the Enlightenment, European culture believed--as do most other cultures--that there was more to reality than we simply experienced: they realised that there was a world which existed outside the "matrix". While the dumber Europeans made up stuff about this other world, the smarter Europeans recognised that there was no way to access this reality through human effort alone. A person needed to be "unplugged" but he could not do it through his own efforts. In Christianity this concept was called revelation.
The real changed occurred around the time of the Enlightenment. Most Christians see the Enlightenment as the beginning of the decline, I don't. These Christians fail to distinguish between the mother and its bastard offspring, Positivism. Positivism (in all of its variants) was a corruption of Enlightenment thinking. The fundamental premise of the Positivists was that there was nothing outside the Matrix, and like Agent Smith, they set about ensuring that any ideas of reality outside it were punished.
Positivism was really a fringe element in European history till about the mid 19th Century when it achieved "critical mass" and started influencing European culture in a meaningful way. I think its important to realise that it's not enough just to have the ideas, one also needs the means of effecting them. Hence my graph from a previous post which Nick Steves took some issue with. The rot in European civilisation really starts when people enough people start getting on board with the notion that the Matrix is all there is.
Strange to think that the Christians are more akin to Neo and his friends whilst the Positivists are the modern day Agent Smiths.
Neo illustrates the philosophical problem.
