The solution of the Monty Hall problem hinges on the concept of information, and more specifically, on the relationship between added information and probability.

As every bookie knows instinctively, a number such as reliability - a qualitative rather than a quantitative measure - is needed to make the valuation of information practically useful.

Underneath the shifting appearances of the world as perceived by our unreliable senses, is there, or is there not, a bedrock of objective reality?

If you don't understand something, break it apart; reduce it to its components. Since they are simpler than the whole,you have a much better chance of understanding them; and when you have succeeded in doing that, put the whole thing back together again.

The problem of defining exactly what is meant by the signal velocity, which cropped up as long ago as 1907, has not been solved.

Entropy is not about speeds or positions of particles, the way temperature and pressure and volume are, but about our lack of information.

Paradox is the sharpest scalpel in the satchel of science. Nothing concentrates the mind as effectively, regardless of whether it pits two competing theories against each other, or theory against observation, or a compelling mathematical deduction against ordinary common sense.