"Here's an easy one: "Race is an entirely social construct." No, it's partially one, depending on how any given society seeks to define it and its implications. But there are basic things such as skin color and hair texture. Even a Martian who'd had no exposure to human "social constructs" would be able to spot those differences. But no Martian, as hard as he tried, could point at a "culture" or to "equality." Those are the social constructs. Those can't be measured in the same way as human DNA."