Self Education: Foundations for understanding markets/investing/trading?

I don't know if WSO is the right place for this question. I've very new to investing and my friend recommended WSO.

Lately I read an article about how a flattening yield curve can impact the market. After reading the article, through mimicry, I can feign understanding, but it would not be understanding.

I will only succeed if my trades are based on my own understanding. With so many different trading strategies, how can I learn the foundations needed to see what works for me and to make intelligent, self driven, decisions?

It is telling, that two traders, with diametrically opposed views, can both be amazingly successful. I need to the style of investing/trading that works with my temperment. I need to have confidence in my trades and my reasons for taking a trade. I need ways to prove that my trade idea is wrong.

I have no experience in economics, accounting, or finance. I do have a B.S. in Physics and an M.S. in computer science. I am not a fast reader. I am not interested in one way of investing or one school of thought. I am interested in understanding the machine. I am not interested in complicated formulas. I don't want a strategy smarter than I am, that sounds dangerous.