I am not sure I do, actually. Given that my metabolic processes are constant, I am not quite the same object that got out of my bed this morning, and given that I am constantly taking in sense-impressions, and processing them, I am not quite the same mind or soul either. If the words mind, soul, prove, we, exist have any meaning.
What would “exist” mean? If I am part of a simulation in an alien battle-computer deciding whether to invade this galaxy I imagine myself part of, I still “exist” in the sense that it behoves me to imagine that I do. Resistance is futile!
So, I can’t prove that I exist, never mind that we exist, but it appears useful to act as if there is a sequence of entities with a certain degree of continuity, which might be referred to as “Clare Flourish”, and that it is in a “world” where there are similar sequences of entities. I act as if my sense-impressions register something other than myself, in a useful manner which allows me to make predictions and decisions- until it doesn’t. I behave like a naïve realist, in other words.
Klovax asked this. She self-identifies as a nihilist. My understanding was that a nihilist believed nothing had value- Oh, OK, then- but her identification moved me to read further: if she finds value in nihilism, it is worth checking out. I turn to my Oxford Companion to Philosophy which tells me that nihilist is more usually a term of abuse, meaning someone who believes there is no justification for values or morality. So when Klovax tells me I have dodged the question, which is true, I could reply that she has no grounds to object to that. I choose to act as if values had meaning. I find hers a wonderful question, and am grateful.
I then had a look at the entry for existence. It tells me that “exist” does not express a property of objects, as verbs like “shine” or “fall” do, but a property of properties- to say “God exists” is to say “the property of God-hood is instantiated”.
This is not a book I get down from my shelves often.
It goes on to say that David Lewis espouses an idea called Modal Realism, in which Pegasus- or, I don’t know, Doctor Who- has full-blooded existence in other possible worlds. Lovely as the thought that The Doctor exists is, Lewis admits he is not “actual”. You see what I mean about “it depends what ‘exist’ means”.
The biggest metaphysical problem is why anything should exist at all. I am unaware whether there is an Answer to this question. When I read that God, angels and demons have necessary existence, but this does not mean that they necessarily exist, I give up on the thought of proving existence.
I do not share enough William Blake.