Judge not, lest ye be judged.

Like many of Jesus’ sayings these words (from the 400 year old Authorised Version) are considered wise advice by many people who are not Christians, and you don’t even have to believe in God or a higher power that could judge you to find them helpful.

That’s because they echo some other of Jesus’ words, versions of which are found in every major religion of the world: do unto others as you would be done by.  In other words, treat other people the way that you would like to be treated.

If you don’t like people judging you, don’t judge other people.

I’ve been trying to remind myself of these words as I watch the news at the moment, because whenever I see President-elect Donald Trump on TV (and I’m still pinching myself that those words belong together) I find judgmental thoughts filling my head – along with quite a lot of other un-Christian thoughts.

For a variety of reasons I’m not going to tell you exactly what I think about Mr Trump, but I hope that, as the Headmaster is always telling you, you will take the time to find out enough about American politics to develop your own point of view – that you will look at the facts.

It won’t be easy, though, because it has become increasingly difficult in recent times to distinguish facts from fiction.

A scary new word entered the Oxford dictionary last year: post-truth.

Scary, because it suggests that many people are no longer very interested in truth.

Indeed, as a friend of mine put it, there seems to be a new Law of Modern Society that for every truth, there is an equal and opposite post-truth.

So how has this situation come about?

AC Grayling, the renowned philosopher and master of the New College of the Humanities who gave a lecture at this School a couple of years ago, believes there are two main causes.

First, as the gap between rich and poor has grown, large numbers of people feel angry and resentful, and so it is much easier to “inflame” emotions over issues such as immigration and to cast doubt on mainstream politicians.

The other key ingredient in the post-truth culture, says Professor Grayling, has been the rise of social media.

It's not the soundbite any more, but the “i-bite”, he says, where strong opinion can shout down evidence.  The whole post-truth phenomenon is about, “My opinion is worth more than the facts.”

There has been much talk recently of “fake news” – especially in connection with the presidential election – and it seems that many people now can’t (or can’t be bothered) to distinguish between fact and fiction.

Type the words “did the” into Google and one of the first things you see is, “Did the Holocaust happen?” and the links will take you to claims that it didn't.  As I say, scary…

But maybe it’s always been like this. 

Professor Grayling tells the story of Adlai Stevenson, the unsuccessful liberal contender in the 1952 US presidential election, who was told: “Mr Stevenson, every thinking person in America is going to vote for you.” And he said: 'Great, but I need a majority.'

Understandably, many people – perhaps the majority – are not interested in politics, but it seems to me that if you’re going to vote in an election – any election – it behoves you to make an effort to find out (as far as you can) what the candidates stand for, and to do some thinking.

This should include finding out about candidates that you don’t expect to agree with, because another problem that has been exacerbated by social media is our tendency only to listen to, read about and follow people or organisations whose views we know and like.

Again, this has always been the case (why would you buy a newspaper that’s going to make you choke on your breakfast?), but social media makes it so easy to fall into this trap.

How many people in your Twitter feed have views that are often the opposite of yours?

The danger of only reading or listening to views with which you agree is not only that you are much less likely ever to change your opinions – and none of us can always be right – but it’s all too easy to start to see people who hold very different views to you as less worthy of respect.

During the US presidential election, members of both camps were guilty of demonising their opponents – of suggesting that they were not just wrong, but somehow evil.

A few years ago the US activist Elizabeth Lesser gave a fantastic TED talk in which she warned of the consequences of demonising “other” people.  She quoted the titles of some of the bestselling books from both sides of the political divide in her country: “Liberalism Is a Mental Disorder,” “Pinheads and Patriots,” “Arguing with Idiots.” As she said, they're supposedly tongue-in-cheek, but they're actually dangerous.

If you need convincing, consider the title of this 20th century book: “Four-and-a-Half-Years of Struggle Against Lies, Stupidity and Cowardice.” Who wrote that? That was Adolf Hitler's first title for “Mein Kampf” — “My Struggle” — the book that launched the Nazi party.

As Lesser put it, “The worst eras in human history, whether in Cambodia or Germany or Rwanda, start like this, with negative other-izing.”

But as the famous Russian author Aleksandr Solzhenitsyn wrote, “The line separating good and evil passes not through states, nor between classes, nor between political parties either — but right through every human heart — and through all human hearts.”  It oscillates, so that, “even within hearts overwhelmed by evil, one small bridgehead of good is retained. And even in the best of all hearts, there remains … an unuprooted small corner of evil.”

None of us is 100% good or 100% bad. 

If you do as I suggest, and read and listen to the ideas and arguments of people with whom you disagree as well as people like you, then you will sometimes be angered or even horrified.

But as the then Deputy Prime Minster Nick Clegg said in the aftermath of the terrorist attack on the Charlie Hebdo office in Paris, “At the end of the day, in a free society people have to be free to offend each other. We have no right not to be offended.”

And when we are appalled by something a politician (or anyone else) says or does our response should not be to demonise, but – as the outgoing president, Barak Obama, said this week – to organise. 

We should be prepared to stand up for what we believe to be right – to join or even start an organisation or movement to fight for what we believe in. 

But we also need to remember that however strongly we hold our beliefs, there must always be at least the tiniest of chances that we could be wrong. 

Which is why, as we denounce our opponents’ ideas, we should try not to judge them as people – lest we be judged ourselves.