glamazord:

I joke a lot about dualism (”two is the onlyest number,” etc.) and its social effects.

But it makes sense that dualism feels right to a lot of people.

It’s in the features of our bodies– most of our features come in pairs.

And when there’s more than two of something, the total number is too large for useful categorization:

• bones (206)
• joints (360)
• lymph nodes (500-700)
• red blood cells (trillions)

The only easily viewable exceptions I’ve thought of so far are fingers/toes (10 or 5 each side).

Dualism is so ingrained that people who attempt to think beyond 2 end up with a 2-sided spectrum instead of considering 3.

Maybe if we evolved from starfish, some people would insist that there are exactly 5 genders.