When I was young I was told there were six colours in the spectrum (I even learned a little song that names them). Now I'm told there are seven - they added indigo somewhere along the line.
I have refused to accept indigo. So far as I'm concerned, there are still six colours in the spectrum.
Now they are telling me that Pluto is not a planet. Again, I refuse to accept that. So far as I am concerned, Pluto is a planet (and so are Ceres, Xena and Sedna).
Sure, there are authorities that will tell me that there are seven colours in the spectrum and eight planets in the solar system. But on what basis am I required to accept their definition?
I have concluded: none. If I decide there are six colours, or twelve planets, that's up to me. And - my take is - there's no reason why society can't allow both.
It is the idea that there is only one distinct number of colours, or number of planets, that is wrong, and not any particular list of them.
Try it. Try thinking this way. It is incredibly, extraordinarily, liberating.