Rivalry causes us to overemphasize old opportunities and slavishly copy what has worked in the past.

A startup is the largest endeavor over which you can have definite mastery. You can have agency not just over your own life, but over a small and important part of the world. It begins by rejecting the unjust tyranny of Chance. You are not a lottery ticket.

Twitter is hard to evaluate. They have a lot of potential. It's a horribly mismanaged company — probably a lot of pot-smoking going on there. But it's such a solid franchise it may even work with all that.

If you think your initial market might be too big, it almost certainly is.

But the indeterminate future is somehow one in which probability and statistics are the dominant modality for making sense of the world. Bell curves and random walks define what the future is going to look like. The standard pedagogical argument is that high schools should get rid of calculus and replace it with statistics, which is really important and actually useful. There has been a powerful shift toward the idea that statistical ways of thinking are going to drive the future.

All happy companies are different: each one earns a monopoly by solving a unique problem. All failed companies are the same: they failed to escape competition.

In the developed world, technological progress means that you can have a situation where there's growth, where there's a way in which everybody can be better off over time.