I don't do manual testing, but I have a system that uses three indicators to generate positions, and it has been useful to look at a spreadsheet displaying how those indicators varied day by day and how they translated into positions and profits and losses. Only knowing at a global level what the Sharpe ratio and vol have been over the last 5 years is not enough to make me comfortable with a system.
Intuitive traders should try to record their thoughts so that the reliability of their perceived patterns can be backtested. Systematic traders should continue to follow the markets they trade to get new ideas to be backested. The distinction between discretionary and systematic may not be clear-cut. Even if you are systematic, as I try to be, you are always making decisions about which systems to trade and in what size.
This is a statement I strongly agree with. From what I have noticed, people who are naturally good at something are often terrible at teaching because they have never had to divide it into smaller pieces so other people can understand as they just "get it" and don't understand how someone else might not get it the same way. It's not in their reality to have whatever they are teaching not be comprehended by people.
I have observed that the best teachers are often people who were not good at something and brought themselves to a 7 or 8. But the best at things are often naturals who are at a 9 or 10 but have no idea why. Rarely you get a natural who gets the concept of explaining things to people who don't already have any knowledge. This happens regularly with musicians. There are some incredible guitarists who cannot teach you how they do what they do... because it's always been how they do it. One of the most talented guitarists I know is a teacher I had years ago. He could not explain to me in a way that made sense music theory and how to play exceptional metal solos. I finally got it, kind of, years later studying on my own. I need to mention that I took an 8 year break from playing guitar during that period, too.
I can't feel the market but did notice every stock I traded had their own idiosyncrasy, personality and behavior. For example, some companies always over delivered earning results, the stock prices went through subtle but different patterns and reactions to systemic market outcome..... Maybe I was just imagining things or just my wishful thinking?
Guess what you are saying is as one of the posts by Simple states knowing what a stock is going to do. At times I KNOW what a stock will do and most of the time I am right. Could be from following the company for lots of years, other times but its not that I think what its going to do but I know. Any way has worked out well for me all ways wondered why my SO asked how I knew and how i could not answer and really does not matter.