How do entrepreneurs who have never been to business school know so much about the fundamentals of business and business strategy?

Entrepreneurs existed long before there were business schools. In fact for thousands of years before- the first business school was created less than 200 years ago in 1819[1]. You learn from employers, mentors, competitors, customers, history, and experience. [1]http://en.wikipedia.org/wiki/Business_school#Notable_firsts

Zuckerberg declared he knew nothing about running a business in the early stages. He didn't study it. Good entrepreneurs are bias towards execution - rather than wasting too much 'precious time' learning text books which are often far far removed from reality and redundant in the situations in front of you. If you had x resource you could do this... etc If I made 100 sales in my cash forecast I could buy a Ferrari. The best entrepreneurs I've seen are making lots of decisions and actions, meanwhile the MBA's are listening to older professors who are behind on the latest trends in social media/ internet marketing etc What matters is absolute objectivity and getting out on the street listening to the customer.

How do birds who have never been to flight school (or taken a course on aerodynamics) know so much about the fundamentals of flight? The same way anybody learns anything. Through trial and error. (Also, through observation, mimicry and some degree of natural instinct.)

If the enterprise seems headed to success in the early days most will gain venture backing and extraordinarily experienced mentor/executives as did facebook, Microsoft, Google and many many others. Additionally, they may have strategic partners that help them gain "delivery discipline". The idea of the incredible entrepreneur making it all on his.her own is mostly a mixture of idolatry and just so stories. This only happens if they keep control of the stock/company. Otherwise they usually get thrown out because they are "dangerous". There Are a few exceptions, but they are usually NOT found in silicon valley.

Fake it until you make it!

Think of an experienced pharmacist. She can name all the medicines in her store. She will even tell you what a particular medicine is used for. Infact when you are sick, you can directly ask a pharmacist for the right medicine :) Experience !

Basically people who never attended business classes n still good at fundamentals just because of their personally practical experiences they had from the start.... What we study in business class most of it doesnt implemented but at some part they are... Most of it comes from practical experiences