Rebecca Coulson is a freelance classical musician and writer, and the Conservative Prospective Parliamentary candidate for the City of Durham.

I once rang up the most brilliant person I knew, and, à la Pilate, asked him to define truth for me. In a sentence. Now I see that the reluctance of his answer didn’t just owe to the thirty-second brevity of our phone call. Rather – ever kind – it was his gentle way of pointing up the hopeless error of my request. Truth isn’t definable in a reducible way: you can’t use simpler things to explain it. And it isn’t a thing itself; it’s more like a property of, or a relationship between, things. Yet, as that brilliant person often claimed, it is unitary and indivisible. So, because I’m going to have to assume you agree with him, I presume you think that truth isn’t relative. If something is true, it can’t also be untrue – regardless of place, time, personal circumstances, or anything. I also assume that we have a pretty similar idea of what truth is. I don’t think these are unreasonable assumptions.

So, why do we find it so hard to extend this to the realm of morality? Why do we struggle to accept that there are such absolutes as right and wrong? Why is even the Pope (recently-admitted violent tendencies, aside) confused about this:

‘It is what my much-loved predecessor, Benedict XVI, called the “tyranny of relativism”, which makes everyone his own criterion, and endangers the coexistence of peoples.’ (Pope Francis, the objectivist?)

‘Everyone has his own idea of good and evil, and must choose to follow the good, and fight evil, as he conceives them.’ (Pope Francis, the relativist?)

Whilst goodness isn’t indivisible like truth, if you have a conception of right and wrong, you should – whatever your conception entails – think it applicable for everyone. OK, we can’t prove objective moral values in the same way that we can prove truths about, say, the UK’s longest river, or, even the existence of the Higgs Boson. But we need to believe that there are such things to be searched out.

Because this is where terrorism, the topic de jour, comes in. To live together in ordered society, we have to accept these empirically-unprovable absolutes – finding (yet constantly reassessing) a justifiable corporate view of what fits into each. If we don’t, we’re vulnerable to those ideologists who not only oppose us, but also want to smash us. With violence. Hell, if even the Pope – who (hopefully) spends his life considering goodness and truth – is confused about all this, then surely we’re putting ourselves in danger.

It’s good that our multicultural society engenders tolerance. And, lately, it’s seemed as if we might be starting to curtail our tendency of letting this slip towards risky cultural relativism. But are we? Have we finally started prosecuting people over FGM because we’ve realised the weakness of deeming things variably right or wrong depending on differing standards? Or, does our seeming objectivity just come from the heavy campaigning, thanks to which we are much more aware of its level of brutality? It’s easy to oppose wrongness when its visceral cruelty is as tangible as that of (a soft acronym like) FGM, Saudi Arabian stonings, or the clinical shootings of people like us in workplaces and shops like ours.

Now that we’re all Charlie, are we going to oppose all terrorism? Or, is it significant – and I’m sorry for entering into the silly word-games game – that it’s mostly ‘je suis’, rather than ‘on devrait toujours être’, or even ‘nous sommes tous’? Is our outrage over Charlie more subjective than objective? Are we just being relativistic in our relativism? What about those terrorists we prefer to christen ‘freedom fighters’ or ‘members of militarist groups’? What about Hamas?

The terrorists have it easy, really. We don’t have dogmatic tracts, or people with guns who can generously force answers into our heads, and keep them there. We don’t even have a written constitution. But we do have laws and established values. And if we think our society is, morally, on the right track, we don’t just need to be confident about this – we also need to be consistent.