There are no set rules, but beliefs. Rules change based on environments, beliefs don't.

If you've read The Hard Thing About Hard Things - Ben Horowitz, you must be expecting to find the below excerpt by Peter Theil from the book.

It took me mulitple readings to understand the depth of it.

There are several different frameworks one could use to get a handle on the indeterminate vs. determinate question. The math version is calculus vs. statistics.In a determinate world, calculus dominates. You can calculate specific things precisely and deterministically. When you send a rocket to the moon, you have to calculate precisely where it is at all times. It’s not like some iterative startup where you launch the rocket and figure things out step by step. Do you make it to the moon? To Jupiter? Do you just get lost in space? There were lots of companies in the ’90s that had launch parties but no landing parties.But the indeterminate future is somehow one in which probability and statistics are the dominant modality for making sense of the world. Bell curves and random walks define what the future is going to look like. The standard pedagogical argument is that high schools should get rid of calculus and replace it with statistics, which is really important and actually useful. There has been a powerful shift toward the idea that statistical ways of thinking are going to drive the future.

With calculus, you can calculate things far into the future. You can even calculate planetary locations years or decades from now. But there are no specifics in probability and statistics—only distributions. In these domains, all you can know about the future is that you can’t know it.You cannot dominate the future; antitheories dominate instead. The Larry Summers line about the economy was something like, “I don’t know what’s going to happen, but anyone who says he knows what will happen doesn’t know what he’s talking about.” Today, all prophets are false prophets. That can only be true if people take a statistical view of the future.

**- Peter Thiel**

Don’t believe in statistics, but in calculus. In a Startup there are no ods.

**- Ben Horowitz**

In the first glance, this statement didn't make any sense to me. It still doesn't, I am not sure if this can be generalised in all cases. For every CEO/Founder, majority of the decisions are based on calculas, they look at the data understand the trend and define their product roadmap/growth. Data is definitive.

But can the definitive calculations of yesterday determine future? If there are pivots are these based on calculas or statistics?

This is the same dillema in stock trade, do you trust the principles of fundamental trading or techincal trading.

It gets tricky to understand that calculas holds true only in controlled environments. As per my understanding, the deterministic results of past are not enough to decide the future, statistics is what defines the future. Technical analysis can't alone win the game, fundamentals has to interfere and define the path.