Losing one of your senses is a very disturbing and often distressing experience. But at times it can occur so slowly and imperceptibly that you hardly even notice, until, that is, it has almost gone. One of the loses we have experienced in the public exchange of ideas is the appeal to, what we used to call, common sense. In just about every big issue that is debated today, common sense seems to have gone AWOL.

Common sense would have told us that the pre 2008 economic tigers could not be sustained and warned us of the collapse. Common sense would have told us that covering the land with concrete, cutting down the forests and piling plastic into the sea would have negative effects on our world and it could come back to bite us. Common sense would have told us that humans are different from animals, that men and women are not the same, that you can’t just decide to change from one to the other, that men can’t have babies, and that an unborn child is still a human being. Common sense would have told is that we are not just a collection of random cells. Common sense would have warned us that before you cut down the tree, you should remember how long it took to grow.  Common sense would have told us that when we empty the bath we should make sure that the baby doesn’t go down the plug hole too. Common sense also would have told us there could be exceptions but that it is best not to rip up the rule book over an exception or a hard case.

So, it is the loss of common sense that distresses me. I often come to a debate thinking “Why on earth are we even talking about this?” Time was when you could close a ridiculous argument, disengage from a pointless debate, halt the indulgence of bizarre and crazy ideas by simply appealing to common sense. Not so now. No matter how crazy or insane or outrageous the notion may seem, you have to do battle on an even field, respect the other view as if it were an equally valid opinion and argue the case from a logical evidential footing. The assumption of course is that all views are equal and should be given the same value and debated with the same rigour and even-handedness. Common sense tells you they are not.

And I wonder how this has come about. Could it be that there is no such thing as common sense? Just a vague but useful tool that has managed to smooth things over the centuries and made it work?  If that was all it ways, it would still worthwhile. But when the foundations are in question there is nothing to build on and so, with the death of truth, comes the death of common sense. If my common sense is different from your common sense, it is no longer common. Yet for any debate to be of value there needs to be some founding principles. If there isn’t, we just end up shouting at each other and this is exactly what happens.

Crawford Mackenzie