Have you ever gotten scurvy before?
Have you ever eaten an orange before? (This includes clementines, tangerines, lemons, limes, and kumquats).
Yes, or you are dead.
Although correlation does not imply causation, the link between eating oranges and being alive is striking.
I am alive, and I ate an orange yesterday. My sister is alive, and she is drinking orange juice right nw.
Picture this: it is the middle of the Civil War, and you are dressed in rags. Your feet are covered in pus filled blisters. You want to die; you are dying. Somehow, you manage to scrape together the five dollars it cost to buy an orange back then. You eat said orange. You are cured.
Picture this: you are toothless. You are a pirate. You have a peg leg and a bird that defecates on your shoulder. Your back is covered in scales and your bones feel like jelly. You plunder and pillage a ship bearing fruit. You eat an orange. Suddenly, your bones become solid again.
You are not a soldier in the Civil War or a pirate. You have most likely never had scurvy. You have eaten at least one orange in your life. Think about the living people you know - how many of them have never had an orange? How many of them are alive?
The results speak for themselves.