Historian Peter Matheson wonders if New Zealand and the world is close to a tipping point on fundamental environmental, economic and social matters, the issue of drilling for oil being a crucial example.
You move on in your thinking, or so you think, but as you turn to your neighbour you realise with a start that she or he does not share your new perspectives at all.
No way.
He or she is still where you were yesterday.
As a historian of the stormy early years of the Reformation I noticed this again and again.
A nun leaves the convent to marry, but her colleagues feel bewildered and betrayed.
Families found themselves split down the middle. Old friends fire polemic at one another.
It's not so different with the current controversy about drilling for oil off the Otago coast.
I find it easy to forget that only a year or so ago I regarded opponents of drilling as dreamy idealists.
At best they got a supercilious tolerance from me.
Today, it's the arguments of the advocates of drilling that I find hard to take.
So what has changed?
I wouldn't discount the articles and books I've read since then, or the lectures I've attended, but it has been the face-to-face engagement with those passionate about the issue that has changed me.
Historians these days are increasingly interested in the emotional field around the great tipping points of history.
We see the world not as it is, but as we are.
What happens when massive shifts in consciousness take place, for example on evolution or gender issues, is not so much that our views change.
It is we ourselves who change.
Find we have to change.
This is not an argument against rationality.
Anything but.
A common misunderstanding is that those labelled ''greenies'' are irrational, driven by ungrounded hopes or fears.
This is not my experience.
The economic, scientific and ethical arguments mounted by the critics of drilling are stringent and, for me, compelling.
Advocates of oil exploration, on the other hand, can be blissfully unaware of the emotional capital locked up in such concepts as ''progress'', ''economic development'' and the like.
It may be the case - and personally I believe it is - that we are at a tipping point of quite momentous consequences for the environment and that this controversy about oil drilling is one particular, but for us in Otago, crucial manifestation of this.
Yet at the moment only a minority, all too easily dismissed as ''greenies'', believe this.
It is true that in places such as Waitati, North East Valley and elsewhere, in academic circles and in many churches, a consensus is rapidly developing that fundamental assumptions about our economic and social welfare are no longer viable.
But this consensus is not yet shared by middle New Zealand.
That, however, is how democracies work.
Agreement is reached only by facing squarely our disagreements, by listening civilly to one another.
In my own church this is precisely where we are at on the ethics of oil drilling. After all, if the answers were simple, they would have been found long ago.
There are of course interested parties who will never be convinced by any arguments, and in the end they will simply have to be swept aside, as has happened at every tipping point in history.
It is in this context that I attended the recent conference in Dunedin on an oil-free future.
It raised, for many of us, new and difficult questions.
It also opened up new options.
Some, including myself, are now convinced it is time to leave the cloistered security of oil and take the first hesitant steps into a new way of life.
Others are not yet convinced.
But if a new approach to the environment is the most urgent challenge of our time, let's try to be tolerant of one another during this difficult process.
It's not, after all, our arguments that have to change.
It's us!
• Peter Matheson's most recent book is Argula von Grumbach: a Woman Ahead of her Time (2013).
