SINCE the age of enlightenment produced the scientific lab, the humble guinea pig has been a synecdoche of experimentation. Barely can our furry friend shuffle three steps without the spectre of a clicking stopwatch; scratch their behind without a phantom tape measure pressed against their claws; squeak in that insufferably high-pitched tone without the ghost of some gadget measuring the decibel count.

Managers of Celtic and Rangers throughout their respective histories must have plenty of sympathy for man’s furry companion.

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To understand the unique phenomenon of the Old Firm, it may be helpful to conduct our own experiment using two of our cuddly little rodent friends (let’s call them Reason and Logic). What would happen if we set them loose? If your hypothesis is that the world would turn upside down, up would be down and left would be right, you’d be wrong. The thing about guinea pigs is that they’re utterly useless creatures. They like being couped up in hutches, safe from predators and benefiting from a boundless supply of nutrition.

Sure, despite their duopoly on claims to every vegetable cut-off and bundle of fresh hay, Logic and Reason will scrap it out for an inflated share of the bounty, but neither is going to go short. Take them out of this controlled environment and they would no longer have such a reliable stream of nourishment.

It’s much like Glasgow’s big, cuddly rivals. Talk of Celtic and Rangers leaving Scottish football – former national team manager Craig Leven recently professed that he would drive them down to England himself tomorrow if he could – has been theorised since before Louis Pasteur started pestering cows’ udders. Both clubs are big enough and ugly enough to survive in the wild, but they’d have to adapt to its ravages. Any notions of annual cup glories, title wins and European adventures would have to be put on hold by supporters. Much better to stick to the cosy hutch of Scottish football, perhaps.

Furthermore, Celtic and Rangers exist in a condition where the domestic cage door is open to an even bigger feeding bowl in the form of the Champions League. There are gates blocking access to this utopia, with bigger animals scoffing the bulk of the bounty on offer once inside, but every so often they sneak in and gobble up some for themselves.

Ask any supporter of these sides and they’ll inform you that domestic success is the bread-and-butter of their club. This stands up to reason as it endorses claims to superiority over rivals and, chiefly, provides a gateway to the Champions League and the riches the competition unleashes. But to truly belong (ie to compete) at this level, both clubs would have to abandon the safety of their Scottish football hutch that provides them with enough nourishment to sustain a comfortable, docile existence. This Catch 22 has been spinning longer than the mouse in the wheel in an adjacent experiment room.

In the world of Scottish football, where Reason and Logic are often set loose, we will continue to judge Celtic and Rangers on their forays into European football. Rangers, Europa League runners-up the previous season, endured a dismal campaign this term akin to being gobbled up by a tawny owl on stepping foot outside the cage, which ended in the ignominy of achieving the worst-ever record in group-stage history. Ange Postecoglou’s first crack at the big time this term, meanwhile, was something of a free hit. Still in the experimentation stage of his “Ange-ball” playing style, the Greek-Australian’s side were largely forgiven for a winless group-stage campaign on account of some heartening displays at home to holders Real Madrid and away to Shakhtar Donetsk in particular.

However, in danger of entering a world where failure is deemed a success, Postecoglou has got to do better next time around. Targeting third place and European football after Christmas is a must. To do that, perhaps he will have to be more conspicuous in his approach to avoid being chewed up by bigger, more experienced opponents at this elevated level. While Postecoglou has done an admirable job in augmenting Celtic’s place at the top of the Scottish game, supporters will always crave progression on the continent and continued failure in this arena will wear thin, even for a figure whom the fans have taken to heart.

With no European football to contend with since before December’s World Cup break, both Celtic and Rangers have gone on prolonged unbeaten runs in the Premiership and it seems practically inevitable that either or both of their names will be carved into all three domestic trophies come May. The hope will be that this is generating enough momentum to fire them into the European arena primed and ready for what comes at them.

There will always be those whose pet-peeve is the Old Firm’s dominance over Scottish football and who want to throw Logic and Reason out the window (just ask Craig Levein). Still, what keeps many of us onlookers in the white jackets gawking at the spectacle of Scottish football is hypothesising what will happen when our domesticated companions go out into the wild of European competition. And no matter how many object to the ethics of the experiment, the guinea pigs won’t be freed from the lab any time soon.