why was "supply and demand" the most important law governing human behavior?

When? Where?

What evidence do you have that the statement is true?

in between 1800-1900 everywhere.

And the Supply and Demand states is summarized as; The higher the price is on a product, the less people will buy it. However, the less the price is, the more people would pay for the product.

I don't think that supply and demand was the most important law governing human behavior in the 19th century. What evidence do you have to support that statement?

Well say you were applying into a college but you had 15 choices to choice from. However, you had to limit the choices to 5 due to expenses and how far it was from home. So you apply into all 5 colleges and you only get into 1 of those 5 colleges. You go to the college but later on had to leave because you didn't have enough money to finish the school year. Then you go into a different college so you can be a teacher, after you graduate it later on leads to a job as a teacher teaching in front of students. Then it leads to living in a place of your own, then it could lead to finding your fiancé, then that could lead to having a child and so on. What I am really trying to say here is that supply and demand could change your life.

Mark? Leonardo? Why the two names?

Yes, supply and demand could change a person's life. But that's not the same as saying that s and d was the most important law governing human behavior. To begin with, very few people went to college in the 19th century.

That is not me that was a different person answering your question.

And oh ok that makes sense, but today people do.

I am dearly sorry for the name confusion. My sister Suzan, and my brother Leonardo, and I are sharing a computer for this website. Mark is a person I do not know but he is the guy who answered your question for my statement of why I think supply and demand was the most important of law governing.