I think, therefore I am. Presumably.
Indeed, today’s problem is what underpinned The Matrix. Human beings were being used like living batteries by the machines, but all the while believing that they were living out their lives in the real world. (Of course, you have to wonder why the machines went to such lengths and why they’d care about humans seeming to have lives.)
Thus we can’t really be certain whether any of this is real. For all I know, I may be the one being deceived or deceiving myself. I doubt it, though. I’m sure (though how can I really know?) that reality is as most people perceive it because if we were all being deceived, there might be inconsistencies in the world. We can, of course, deceive ourselves. I know that I can misinterpret information such as the time when I was going to school one day and thought I saw my Mum’s car. The car turned out to be the right make, but wrong colour (it was hard to be certain of the colour in the morning light) and wrong driver, who happened to live across the road from us. But although my initial perceptions were wrong, it was a matter of misinterpretation not a gross violation of reality.
And I know of other occasions when my perceptions have been mistaken but I’ve clearly not been misled. It’s rather like that picture which might be table legs or a vase, or the duck bunny, or those magic eye pictures when you see something, but not the thing you’re meant to see.
It also seems rather pointless to worry about such matters because we’re always having practical demands made of us by others. I could say that none of this is real, but if I did that, I’d soon be out of a job, have no money, and be out on the street. It wouldn’t help me on iota to sit on the kerb repeating the mantra, “None of this is real.” Next thing you know, I’ve starved to death and found out the hard way that whatever we might think of reality, there are some things we can’t avoid such as eating and drinking.
If Descartes said that he thought, therefore he was, he might’ve observed that hunger wasn’t something you could pretend not to have.
As our long journey through problems in philosophy comes closer to its end, we find ourselves faced with the issue of the meta-problem, but that’s for tomorrow.