When a lay person asks a scientist Why are we here? or What is the purpose of the universe? they are presuming the existence of some deity, creator of man and the universe who has motivations. There is no such deity, so the questions are meaningless. However, people exist and they are free to assign purposes, relative to themselves, for everything. The human purpose for the horse is recreational riding. However, that not likely the way the horse sees it.
What actually happens if you sign up for a Christian purpose, is some schmuck will assign you one. He claims to know the mind of god, and he claims that’s god’s purpose. But he just pulled it out of his ass.~ Roedy (1948-02-04 age:69)