Ivan Pavlov

It has long been known for sure that the sight of tasty food makes a hungry man's mouth water; also lack of appetite has always been regarded as an undesirable phenomenon, from which one might conclude that appetite is essentially linked with the process of digestion.

If a man made himself an expert in any particular branch of human activity, there would result the strong tendency that a peculiar aptitude towards the same branch would be found among some of his descendants.

You don't need the iPhone: you have the most exquisite apparatus in the known universe sitting right in your head - the most complex organization of matter in the entire universe. And here are we, feeling a little depressed, feeling like we're not getting where we need to be, when really you might be exactly where you need to be.