What I Know But Cannot Prove

sxm_beachI came across a finance blog asking about the limits of statistical proof in the world of investing.

It reminded me of an old surgeon who shared, “Half of what I learned in med school turned out to be wrong.”

So I ask you…

What do YOU know but can’t prove?

You may talk about your faith.

But for me, the lesson runs deeper.

What is the ONE thing of which I can be certain but can’t prove?


I start by asking myself, what did my grandparents believe that we now know is false?

I came up with smoking and trans fats. You’ll probably get a more exciting list!

Anyhow, the lesson isn’t to switch margarine brands…

The lesson is to be skeptical with my own beliefs.

I can be certain that some of what I now know will turn out to be incorrect for my grandchildren.

However, I can’t prove which of my current facts are incorrect.

I can only be certain that some of my knowledge is wrong.

So I should be careful when I find wise people on both sides of an issue.

I might be best served by acting as if they were both right.


This article influenced by Russell: Sceptical Essays (first edition 1928!).

The Lindy Effect is a good way to sort knowledge. The longer an idea lives, the greater its life expectancy.