Idiom: Let Nature Take Its Course
My daughter Isabella is 17 years old. She just graduated from high school and I am worried about her. The thing is, she has never dated anyone. All her friends have gone on dates but her.
Should I try to help her? Or should I let nature take its course?
Ted: My friend didn't study at all last term for his algebra class. I took the final exam one day before the rest of the class. After the exam, he wanted me to give him all of the answers.
Irene: He wanted you to cheat?! Well, did you give him the answers?
Ted: Oh, no. I let nature take its course: he failed the exam.
Meaning: To let nature take its course means to let things happen naturally with no interference from an outside source.