In love, there is only love, no mechanics. It's hard to say literally, but his main meaning is very clear, that is, in front of your family, you will be rewarded for your efforts. If you only focus on your career and have nothing to do with your family, you won't get a family in the end.

The word "mechanics" has two meanings: first, it refers to his research work and his career. Second, the girl's "flying" and falling from the building are all practicing his mechanical principles.

"In love, there is only love, no mechanics" is actually dad's self-mockery: if you give a little love, you can get love. Even if you have thoroughly studied mechanics and know what will happen if your daughter jumps off a building, if you don't educate your children (educating children is one of the responsibilities of a father), that is an armchair strategist, and you have no sense of responsibility for your family and even society. You are just your own mental plaything.