Natural, artificial, and smooth

Unlike the everyday sense of the word, the scientific meaning of natural includes man-made and not just non-artificial things.

To avoid the uncomfortable ambiguity arising from the apparent lack of distinguishability related to the terms natural and artificial, we try to forego using them as much as possible.

Since natural also can refer to something “of or in agreement with the character or makeup of, or circumstances surrounding, someone or something” [Lexico], whenever possible, we are using the word smooth to convey a similar meaning “(of an action, event, or process) without problems or difficulties” [Lexico].