Reality, in the common sense cum positivist meaning of that word, is what was usually missing from modernist science and the modernist era : its vast missing middle.
At the top, Reification and Biology had created something called "The Jewish Race" but you couldn't actually touch or taste it or definitely define it.
But if it did exist, at the bottom all its members could certainly be reduced to nothing more than the multiples of then tiniest known bits of mass and energy : protons, electrons and neutrons.
Chemistry and Physics told us so.
(Not that you could see those sub atomic objects either.)
But what was missing was something or someone you could actually see and touch.
The missing bits in the middle , in the day to day reality where we humans touch see hear and taste things.
Missing from all of modernist science was a someone you could accurately define the concrete limits of.
Say an actual individual "Jew" , as vaguely defined within the nebulous concept of "The Jewish Race".
Someone like the real Erin Green : born Aaron Green in East London, named after his father who was raised as an active member of the Jewish religious faith back in his native Poland.
But as an adult, Aaron senior became non-religious, particularly after he met an Irish-born woman raised as a church-going Catholic. She too became non-religious after she married Aaron senior.
Their son, Aaron junior changed his name, as an adult, to Erin as a sort of oral pun honouring both his mother's and father's heritage.
Now he is living in occupied France in 1941, after having met and married a French woman, of traditional French atheist background, while on holiday in Nice.
Suddenly the Germans arrest him, his wife and their children as being "members of the Jewish Race" and start sending them forward on a trip to the fatal showers.
The Nazis at least agreed with many legislatures of the American South in not knowing any arithmetic.
They lined up to defy reality and realism by claiming that far less than 1% of your genome was more potent than the other 99.99% of your genome in defining your origins.
In other words, that tails wag dogs, not the other way around.
"Just one drop of black or jewish blood defines you forever as Negro or Jewish".
Whatever if any 'race' that Erin's children belonged to, it was the mixed up, muddled up human race : but then Reality is like that.
Modernist science is simple ; Modernist reality is not...