If little else, the brain is an educational toy. Why it may...

If little else, the brain is an educational toy. Why it may be a frustrating play thing - one whose finer points recede just when you think you are mastering them - it is nonetheless perpetually fascinating, frequently surprising, occasionally rewarding, and it comes already assembled. [...] Alas! the brain is a toy that plays games of its own. Its very most favorite game is the one-thing-leads-to-another game.