To argue with a man who has renounced the use and authority of reason, and whose philosophy consists in holding humanity in contempt, is like administering medicine to the dead, or endeavoring to convert an atheist by scripture.
“Why” is the question word that asks for the “reason” behind things. However, “reason” can mean both the cause that leads to a specific outcome (Why do objects fall? Because gravity pulls them towards the earth) and the purpose behind a specific outcome that will be fulfilled after its realization (Why did you turn on the oven? Because I want to bake something).