Reasoning from first principles
Kevin Rose (founder of digg.com) recently interviewed Elon Musk (founder of Tesla, SpaceX, PayPal).
The most interesting question was about Musk’s advice to aspiring entrepreneurs. He gave two main points:
First, seek out negative feedback. We love to be praised and hate to be criticized, so we ignore negative feedback as a defense mechanism. Another problem is: the people whose opinion we value, are typically the same people who wouldn’t want to hurt our feelings (friends, family, close colleagues).
His second piece of advice was reason from first principles - meaning drill down to the most basic ideas, ones we know are true, and build up. Electric cars are based on the first principle: responsible energy production and consumption is vital. He chose space exploration to colonize other planets (thereby protecting the survival of humanity - a very basic principle).
The enemy reasoning by first principle is reasoning by simile. An example simile-based reasoning is, “Hardware startups are impossible because all the successful startups I can think of are software.” The implication being good startups must be like recent successful startups.