Meditating over this statement, we eventually realize that this is pretty much all we actually will ever know with certainty.
To illustrate this, let’s look at a very lucid dream we might have experienced once. I, for example, remember one where I had gained many riches in the form of money or gold. Not sure what exactly it was, but I remember that I could really feel this valuable possession in my hand. If you right now take your mouse into your hand and feel its surface, its weight, its temperature – this is very similar to how I experienced these riches.
Then, to my great dismay, the thought crept into my mind that I will be waking up. It became more and more certain that these riches would be gone when I woke up, so I fought waking up. If you ever tried to not wake up, you know how hopeless this undertaking is. As I slid more into my waking state, the thought became more real that there was nothing in my hand, yet I could still feel it.
I ended up having to consciously open my hand to convince myself that nothing would fall out of it – and, obviously, nothing fell.
Looking back at that incident I could not help comparing it with my immediate certainty that I sit here in front of the computer screen, typing along on my keyboard and definitely feel the keys moving under my fingers. I feel my feet touching the carpet, I sense its structure and temperature – all very comparable to my sensations of the riches in my hand while I was dreaming (as I know now.)
Why am I so sure that my perceptions of the environment I experience now are different than my perceptions while dreaming? Looking at it philosophically, I have to admit that this certainty is completely unfounded.
We perceive our environment through our senses and that dream-experience showed me clearly that I can not trust my senses. There is no proof possible that this table I am sitting at is something that exists outside of me. Any means to prove its existence depends on my senses:
- I can touch it – my sense of touch
- I can see it – my sense of vision
- Somebody describes it to me – my sense of hearing
et cetera.
There are perceptions, we would all agree, that are not quite as solid as these perceptions of elements of the physical world. Let’s take a religious perception for example, where somebody is certain that she experienced god. For this person it might be as real as the pain I feel when the hammer hits my finger instead of the nail. But most people will agree that this is a more subjective reality.
In principle, though, there is no difference between these perceptions.
Therefore you will have to accept as you read this, that the existence of a person who wrote these lines is purely a matter of faith – you believe, that there is, or was, a person who sat at his computer at one time and wrote these words – but you certainly have no proof.