There probably isn't one single overriding reason why so many people like these two, in every country and in every time, feel the overwhelming necessity of 'knowing' that Reality can actually be reduced to something very simple.
For why they need a reassuring mental touchstone of simplicity, underneath reality's apparent surface complexity and seeming chaos.
Each of these poor unfortunate individuals comes to feel that necessity as a result of their life circumstances and life experiences handing them a unique bundle from a grab bag of precipitating 'push' factors.
the wonderful Kaleidoscope of Life
Others, like myself, positively thrive on the vivid kaleidoscope of chaos and complexity, variety, and get bored beyond insanity by the mere thought of the predictable same old same old from the Big Bang to the end of Eternity.
What I do share with the reductionists is a willingness to assume - for now - that a few important fixed laws of Nature may well operate everywhere in this (and possibly other) Universe and will do so for all time.
But I have never ever had any doubt that a few laws (because they must be different for each other, by definition) can still conflict into complexity and chaos.
Reductionists vaguely sense this too and this fuels their need for finding a single overriding law, The Theory of Everything.
There were only a few simple fixed rules in the Canadian Army Reserves as well when I joined up just after my 16th birthday.
One was you simply had to turn up at the rare Inspection Parades and the other was you had to turn up as neat as a pin.
Of course one of my first such Inspection Parades was in the typically wet blowly snowy Nova Scotian winter, a Parade to be held at the very height of a brief but intense storm.
Couldn't delay the parade even by one hour or so till the brief Nor Easter blew through, oh no.
So most of us didn't arrive at all, or arrived shockingly late well after the event, or arrived on time but soaking wet clean through their great coat, serge uniform and underwear to the skin.
That was me : I had walked, ran really, all the way from my home in South Dartmouth all the way up on and down Dartmouth's horrendous hills to the bus terminal at the bridgehead.
There I found I had to walk over the bridge, exposed to literally dangerously high winds threatening to toss me off it, for a mile or so and then on across central Halifax in comparatively sheltered conditions to the Armoury.
I could either arrive on time or I could arrive with my uniform in ship-shop shape : the results would depend on which law had greater force upon me.
Similarly, I intuitively sensed that basic Reality varied so widely as it did because it was dependent on the results from the sum of four widely/wildly different (again, by definition) basic forces of Nature conflicting with each other in a locale.
Reductionists may insist that the Elements, deep down are never ever fundamentally different.
But in fact, under varying local conditions, the elements' phases may differ so widely as if to seem, to our eyes, ears, tongue and nose - if not to our minds - as if they were different creatures from alien universes.
The wondrous gases of Jupiter
So the elememtal gases in the core of Jupiter remain gases, yes, the reductionists are right on that, but under such great pressures that they act like molten metal.
Similarly, in the minds' eye of my Army bosses, the two fundamental rules of Inspection parades seems to act in smooth tandem in a simple reductionist world, but back here on Earth, in my 'boots on the ground', I was there on time but my uniform soaked to the skin - the two rules, in these local conditions, had conflicted and one prevailed : be there on time.
I had chosen wisely, if foolishly - could have been easily tossed off the bridge into the frigid waters a hundred metres below.
For my real boss, my RSM, together with my officers, overlooked my mess of a uniform completely, impressed that the skinny new recruit (almost rejected as medically unfit for being too thin) had actually made it all the way from South Dartmouth through a fierce storm, on foot and on time.
I felt that he would - I had seen front line photos of WWII era army heroes and they had looked anything but neat - I sensed that if you want to do great things, you have to get dirty, you just have to get entangled with messy Reality.
As it so happened my RSM, whose name was Marshall like me but was no relative, was the very last member of the regiment who had actually served in WWII.
He had seen lots of dirt and chaos and rules and he knew what really mattered when and where...