Clearly the guys who wrote the only comprehensive introduction to a topic don't want to share their knowledge.

The previous comment was not directed towards the authors of this book.

They are trying to help you get a correct intuition. If you have never approached things this way, there are almost certainly very large holes in your understanding. Not to say that everyone needs to be formal all the time, but you need to sometimes.

> If you have never approached things this way, there are almost certainly very large holes in your understanding.

When anyone tells me that X is the ONLY way to do it, almost exclusively I have found them wrong - beyond data science. Formalism is a means of communication, not the end. You can always communicate ideas without formalism.

FYI, I am a Ph.D Computer Science and a practicing Data Scientist for many years now.