The pre-Socratic Greek philosopher Parmenides taught that the only things that are real are things which never change... and the pre-Socratic Greek philosopher Heraclitus taught that everything changes. If you superimpose their two views, you get this result: Nothing is real.

The pain, so unexpected and undeserved, had for some reason cleared away the cobwebs. I realized I didn’t hate the cabinet door, I hated my life… My house, my family, my backyard, my power mower. Nothing would ever change; nothing new could ever be expected. It had to end, and it did. Now in the dark world where I dwell, ugly things, and surprising things, and sometimes little wondrous things, spill out in me constantly, and I can count on nothing.

The painting showed a hairless, oppressed creature with a head like an inverted pear, its hands clapped in horror to its ears, its mouth open in a vast, soundless scream. Twisted ripples of the creature's torment, echoes of its cry, flooded out into the air surrounding it; the man or woman, whichever it was, had become contained by its own howl. It had covered its ears against its own sound. The creature stood on a bridge and no one else was present; the creature screamed in isolation. Cut off by - or despite - its outcry.

Imagine being sentient but not alive. Seeing and even knowing, but not alive. Just looking out. Recognizing but not being alive. A person can die and still go on. Sometimes what looks out at you from a person's eyes maybe died back in childhood.

Fat realized that one of two possibilities existed and only two; either Dr. Stone was totally insane – not just insane but totally so – or else in an artful, professional fashion he had gotten Fat to talk; he had drawn Fat out and now knew that Fat was totally insane.

So we and our elaborately evolving computers may meet each other halfway. Someday a human being, named perhaps Fred White, may shoot a robot named Pete Something-or-other, which has come out of a General Electric factory, and to his surprise see it weep and bleed. And the dying robot may shoot back and, to its surprise, see a wisp of gray smoke arise from the electric pump that it supposed was Mr. White's beating heart. It would be rather a great moment of truth for both of them.

In one of the most brilliant papers in the English language Hume made it clear that what we speak of as 'causality' is nothing more than the phenomenon of repetition. When we mix sulphur with saltpeter and charcoal we always get gunpowder. This is true of every event subsumed by a causal law in other words, everything which can be called scientific knowledge. "It is custom which rules ," Hume said, and in that one sentence undermined both science and philosophy .