Jacob

“For, after all, how do we know that two and two make four? Or that the force of gravity works? Or that the past is unchangeable? If both the past and the external world exist only in the mind, and if the mind itself is controllable – what then?”
― George Orwell, 1984

“I suppose therefore that all things I see are illusions; I believe that nothing has ever existed of everything my lying memory tells me. I think I have no senses. I believe that body, shape, extension, motion, location are functions. What is there then that can be taken as true? Perhaps only this one thing, that nothing at all is certain.”
― Rene Descartes

“Contrariwise,' continued Tweedledee, 'if it was so, it might be; and if it were so, it would be; but as it isn't, it ain't. That's logic.”
― Lewis Carroll, Alice’s Adventures in Wonderland / Through the Looking-Glass

“Never put off till tomorrow what may be done day after tomorrow just as well.”
― Mark Twain