Do we really know?
Do you understand gravity? There might be multiple answers to this question. Some people might say that gravity is the curvature of space-time. Some who haven’t studied Einstein’s work might say that gravity is the force that pulls objects towards each other. Some people might say that it is the force which the Earth exerts on us and that is why everything is pulled downwards. All these are answers that are theoretical in nature. A toddler will not be able to explain gravity in any of these ways. But still they do understand that if we hold a ball up and drop it, it will fall down. All of us, before we learn about gravity in physics class, understand it in this very practical way. ...