Well I said people's ability to be objective is the same. Some people may be very un-objective, but that has to do with the way they think about things. And we don't *truly* know what makes something *truly* objective, as people make new arguments about what is considered to be objective or not, and they move onto that if that's a better way to be objective.
How to be objective in a scientific way is a relatively new concept that was only introduced after the Enlightenment. And that has to do with the new philosophies that people came up with, or the way they think about things. I'm sure that people were very un-objective thousands of years ago, or during pre-historic eras, as they believed in myths and superstitions. Yet our brains then and now are still practically the same. Basically, we know how to be objective because we go to school and we get educated and we have a whole culture and social context on how to be objective and what makes something objective.
People don't really have an inherent way of being objective, especially as Socionics claims. You can't say that one is a Te type, therefore he is automatically objective. Because that doesn't explain how he's being objective. Besides objectivity is made by an argument, not who's making the argument.