You are all you've got.

In a lesson on the psychology of chess competition found in Chessmaster 9000, Josh Waitzkin says:

You are all you've got in chess.

Sometimes it's tempting to overestimate your opponent and make a blunder out of fear. But you should simply ask yourself what your opponent's plan is, and whether it is a good one. You have to analyze the game with the processing skills that you've got within your own mind, and trust your own conclusions, because you are all you've got.

Outside the game, you can talk to others. But is it really any different? You still have to process what they say. You have to process their arguments. You have to weight their testimonies according to a heuristic of your own design.

You are all you've got in life, too.

When my little sister Laura was really young, she would hold up her left hand and, showing three fingers on her right, she would sweep down four of the fingers on her left hand, saying:

Five, take away three is... one!

Laura didn't understand how subtraction worked. When she first learned how to perform subtractive operations, it was only because she went through the steps and trusted that the conclusions were correct. It wasn't because she apprehended the concept with her mind.

Somebody sold her on the validity of a method of subtraction.

I experienced something similar as an adult. I had to do some calculus in a physical science lab. I was sold on the method. I performed the steps in the right order and confirmed the conclusion in the back of the book. And I trusted it. But I still don't fully grasp the genuine mathematical truths of each step. I don't really actually fully know why it is that such a list of steps produces the correct answer to a given problem.

I couldn't have invented calculus. I just trust that it is veridical if done properly.

I am sure Laura has since been able to fully grasp what is being represented when subtraction is performed. I am sure she now understands why 5 - 3 = 2 and not just that it is so.

But even still, hasn't she just been sold on the concept of subtraction?

Isn't it true that subtraction just somehow makes sense to her? She is capable of reason, but even reason is something she came to trust.

Think about it this way: there are some people who say that reason is their highest authority. Others disagree. But on what basis?

You are all you've got in life.

When evidence stacks up over your head on both sides of an argument, it's tempting to mistrust yourself, and make a blunder.

This makes me think. As the evidence in favor of a position builds, my certainty builds. But at what point should I start believing in something, if I cannot find a conclusive, sound, deductive argument for or against it? At what point do I reorient my life? At what point in the process do I start living as if it were true? It has to happen sometime. And it will happen when I feel satisfied that I have evaluated enough evidence.

Enough.

What determines that threshold?

Have you ever had somebody explain something to you and they got so upset because you didn't just understand it and believe it at the first go-around? They thought it was so obvious - it was like simple math!

But you weren't sold on it yet.

You had to first understand it, then meditate on it for a little while. And in merely understanding it and meditating on it, you saw its truth. The person was frustrated because there wasn't anything more simple they could say to convince you. The truth was self-evident. And yet you somehow didn't get it the first time.

Why did you get it the second time?

All any of us can do is estimate the best fit lines through the stars.

Does this mean one should throw out reason?

For me, quite the contrary.