What if the world began just as you were reading this? And before you had read these words there was no one, no thing, nowhere. How would you know? Well of course you’d know, I came from the time before just now, from the past, travelling through time at one second per second. And before now, was then, and while I was there, I saw someone, something, somewhere. Right? It is in my memory.
But what is memory? It’s just an arrangement of neurons in our brain. Some neurons stimulate the ones they’re connected to and some inhibit (they may even stimulate some and inhibit others at the same time). In this aspect you can draw a parallel with machine code, where it is the arrangement of 1s and 0s that are meaningful and not the 1s and 0s themselves. So a unique arrangement of neurons in our brain is the shape a memory takes, and you recall a memory when these neurons fire. An interesting thing about memories is that they’re not just visual, on the contrary, sound, odour and touch often trigger a stronger recollection of memories from long ago. While you’re living the moment that’ll become a memory, the stimulus that your senses receive becomes information, that is stored in the form of a new arrangement of neurons. And some memories also carry with them the state of mind that you were in, this is what leads to nostalgia, as a stimulus causes that arrangement of neurons to fire which was made when you were happy, and life, to you, was different; and in that moment your brain creates that reality again, and you live it for a few moments. This is because, the recollection of a memory gives to your brain the same stimuli it received when the memory was made in the first place.
So how would you know the difference if you came into existence with exactly this arrangement of neurons in your brain? How can you tell if what you remember even happened?
But all of these things around me, they couldn’t have just materialized out of thin air and exactly how I remember them to be. Indeed that may be very unlikely (not impossible, however unlikely it may be) but the question is how would you know? Our memories aren’t even as reliable as we think they are. Presumably due to how memory formation evolved in animals, each time we recall a memory we actually reconstruct it partially, which makes them subject to change. They aren’t etched in stone rather they are moulded on clay, in braille.
Now let’s take a step further, how do you know that the present exists and is true?
Even if the past might exist only in our heads, it must be true, without a doubt, that the reality around us in the present exists. It is there and it is true because we are there to witness it. Eyes aren’t subjective, they are biological light detecting machines. What they pass on, is pure factual information. However, that information is dealt with by parts of our brain before we actually perceive vision. And the same goes for all our other senses. So what if this chain of events starts in the brain itself. Our brains are capable of wholly simulating the reality around us because our brain itself controls what we perceive (Much like how during recollection of memories, our brain goes through the exact motions it did when the event itself took place). How would we be able to tell the difference?
We are alone inside our minds, even after having made countless mechanisms to connect to what is not us. We can never truly know something without a doubt. We can never know truly what it is like to be something we aren’t already. Because we are alone inside our minds, governed by molecules which themselves are lifeless but somehow give us life.