Believe it or not, it is entirely true. It’s not that we one day wake up with the Earth having a gravitational pull that’s 1/2th of what it was the previous day.
Physics takes a look at the Laws of physical existence, yet in similar fashion emotions, thoughts, and all of the reality operates under strict Laws. Otherwise, everything would be in complete Chaos, would it not? Life is a mechanism where every action has an equal and opposite reaction that maintains balance.
No books or knowledge will give you this understanding besides the necessary awareness to SEE it.