[anonymouskimmer]

Words tend to have compound and contextual meanings, so it's very rare for one word to have one opposite. Look at lists of synonyms and antonyms.

Another opposite of "natural" is "designed", and another opposite of artificial is "by chance".

[digging]

Designed is a synonym of artificial.

"By chance" is also an accurate descriptor of natural intelligence.

Not sure if you were making a point, but your comment backs up the assertion that "natural" was a better choice than "real" in that sentence.

[anonymouskimmer]

The point I was making is what I wrote. Words have multiple meanings, and synonyms are similars, not identicals.

[visarga]

artificial literally means "made with skill" or "artistic"

[anonymouskimmer]

Merriam-Webster literally lists 5 distinct definitions of "artificial" with two of those having two sub-definitions.

[andrewprock]

i.e. artifice-ial