Other traits like height, health, beauty vary and are influenced by genetics. Intelligence varies between species, and is therefore, at least in part determined by genetics.
Presuming that there are only mentally disabled and normal people is the weird hypothesis. The baseline idea should be that it varies just like health and height. Affected by both genetics and outside factors such as malnutrition and injuries.
This is very nicely put. I wish I had thought of this phrasing when I posted my original comment. The point of my comment was to mention that there are heretical ideas that people won’t discuss in other areas of intellectual inquiry. That was the relation of my comment to the article.
Presuming that there are only mentally disabled and normal people is the weird hypothesis. The baseline idea should be that it varies just like health and height. Affected by both genetics and outside factors such as malnutrition and injuries.