To adapt to the reality of scale, meanwhile, Musk employs a number of other strategies. We'll start with first principles, which is a lesson he borrowed from physics. "Physics training is a good framework for reasoning," explains Musk. "It forces you to boil things down to their most fundamental truths and then connect those truths in a way that lets you understand reality. This gives you a way to attack the counterintuitive, a way of figuring out things that aren't obvious. When you're trying to create a new product or service, I think it's critical to use this framework for reasoning. It takes a lot of mental energy, but it's still the right way to do it."

In life you must often choose between getting a job done or getting credit for it. In science, the most important thing is not the ideas you have but the decision which ones you choose to pursue. If you have an idea and are not doing anything with it, why spoil someone else's fun by publishing it?

[Scientists whose work has no clear, practical implications would want to make their decisions considering such things as:] the relative worth of (1) more observations, (2) greater scope of his conceptual model, (3) simplicity, (4) precision of language, (5) accuracy of the probability assignment.

Success, which is not always a proof of merit, depends more often on the choice of a subject than on its execution.

Certainly one thing that I've learned is that it is important to pick a problem based on how much you care about it.

He went to the Palo Alto public library to read about rocket engineering and started calling experts, asking to borrow their old engine manuals. At a gathering of PayPal alumni in Las Vegas, he sat in a cabana by the pool reading a tattered manual for a Russian rocket engine. When one of the alums, Mark Woolway, asked him what he planned to do next, Musk answered, “I’m going to colonize Mars. My mission in life is to make mankind a multiplanetary civilization.” Woolway’s reaction was unsurprising. “Dude, you’re bananas.

Moral: to the extent you can choose, work on problems you think will be important.

A scientist’s work is determined by two things: his interests and those of his time. Everything has led to this.

[T]he basic decisions are... about aims... what is desirable... the greater good or the lesser evil in the case of conflicting aims... what sacrifice we are willing to make for a certain achievement, and at what point the sacrifice outweighs the advantages.

Many if not most of his decisions are thrust upon the president, out of the blue, by events beyond his control: oil spills, financial panics, pandemics, earthquakes, fires, coups, invasions, underwear bombers, movie-theater shooters, and on and on and on. They don’t order themselves neatly for his consideration but come in waves, jumbled on top of each other. “Nothing comes to my desk that is perfectly solvable,” Obama said at one point. “Otherwise, someone else would have solved it. So you wind up dealing with probabilities. Any given decision you make you’ll wind up with a 30 to 40 percent chance that it isn’t going to work. You have to own that and feel comfortable with the way you made the decision. You can’t be paralyzed by the fact that it might not work out.” On top of all of this, after you have made your decision, you need to feign total certainty about it. People being led do not want to think probabilistically.

The main reason for choosing a project is not really the renown of the director that's making the project. I feel like it's the fact of an actor to constantly want to do different things.

Choosing the priority is as important as working on it.

The art of measuring, as precisely as possible, probabilities of things, with the goal that we would be able always to choose or follow in our judgments and actions that course, which will have been determined to be better, more satisfactory, safer or more advantageous.

You need to decide what you're interested in.