The classical skeptic hypothesis:

 

You know nothing, I don't claim to know you know nothing only that knowledge itself is unattainable. To have knowledge you must be 100 percent certain of a justified True belief.

I believe I am sitting typing a thread about brains in vats but I cannot be 100 percent certain because there is a small chance (Very small) that I am mistaken therefor I do not know I am sitting here typing.

You can say, "Here there skeptic that is an unrealistic definition of knowledge, of course you can't be 100 percent certain." Then how can you say I know my name is X, but I am not certain...

 

So tell me why do you think you are reading this and not a brain in a vat led to believe in a reality that doesn't exist.

I have been thinking about this lately and I think I have a reasonable answer, I will post it in a day or two. (It's nothing fancy so don't get your hopes up.)

oh dear God, not Another Matrix type thread again

Sorry if there have been numerous matrix type threads, I find the thought matters and if there is an answer it matters also, Why stop at the matrix there have been many movies and books dealing with this problem in philosophy?

 

Well to get the ball rolling how about,

I believe I am here because... If I were a brain in a vat (BIV) then everything I actually know about brains and vats is false, they are just signals to the brain (my brain?).

One step further, If I want to type, do I send a signal to the Vat from my brain and the vat responds accordingly by relaying sensations of feeling the keyboard keys and sounds of clicking ( a two way system), Or a more reasonable scenario, I never wanted to type, I never want anything If the simulation is good enough to fool my senses why not fool my thoughts (one way system).

If the later is the case and we are passively experiencing a simulation we have no free will or consciousness.

So why not?