How much knowledge of the world is learnt through words? We know a lot of common sense about the world. Things like "to buy something you need money".

I wonder how much of this common sense comes about through actual someone explicitly telling you the instructions "You need money to buy things". Which we store in our brains as a sort of rule. As opposed to just intutively understanding things and picking it up. 

I am imagining children playing at shop-keeping and saying things like "I give you this and you give me that". And other children not quite understanding the concept of buying things until being told by a teacher.

If so, giving a computer a list of common sense rules likes these is no different to teaching a child. So I am wondering why this area of AI research (semantic webs etc.) has been frowned upon in the last decade in favour of trying to learn everything through experience like deep neural networks?
If I understand correctly, what you are looking for is called "common sense reasoning" in NLP research.

Research in this field revolves around benchmark data sets, where good performance indicates some ability to do common sense reasoning. Here is a nice collection of data sets and research by Sebastian Ruder:

http://nlpprogress.com/english/common_sense.html



In the end, the main question is not


  How much knowledge of the world is learnt through words?


since it is virtually unanswerable if asked in this form. A question that is answered in NLP common sense reasoning research is


  Out of 100 specific decisions that my model needs to take, for how many does the model show the ability to reason correctly?