Threat of terrorism is an incurable condition we'll have to live with
Even in the midst of chaos and horror, while the police were screaming at pedestrians to run and the dead and injured had yet to be removed from the streets, there was cause for quiet optimism in London.
All over the city, in bars, cinemas and clubs, the night went on as before.
Those reading the news on Saturday night on their phones were not entirely as before, of course.
Three days after the attack, it's still too soon to shrug off the atrocity with the insouciance of the battle-hardened veteran, though sadly that day will come.
There can be no victory over the terrorists in choosing not to overreact to each monstrosity, whether as sophisticated as Manchester's or primitive as in Borough Market.
These terrorists were dead before there was any reaction. No future terrorist who shares their intent is concerned about the effect of their crimes.
They are no more cowards and losers than heroes or martyrs.
They are plain and simple nihilists to whom killing is the be all and, more so, the end all. Sticks and stones won't hurt the bones of those rendered corpses by police bullets, so why waste bravado on empty words?
But there is a victory for Londoners in adapting to this reality as quickly and without histrionics as they appear to be doing.
The attacks will not stop. The more Islamic State (IS) sees its 'caliphate' being swept into the dustbin of history, the more home-grown disciples in Britain will lash out.
In medical terms, this brand of terrorism is not a cancer. It can neither be cured by surgery nor kill what people are.
It has killed individuals, each of whom it is a duty to mourn and a privilege to remember. But, to a democratic society, this is a chronic condition, like diabetes, that people must learn to manage.
This is a time to be heart- broken for the victims, disgusted by the perpetrators and happy that it's only the usual suspects of professionally deranged clickbait practitioners who conflate the nihilistic insanity of a minute few with the beliefs of a global religion followed by more than a billion.
No one should go overboard in congratulating themselves, as Mancunians or Londoners or Britons, for not wanting to punish Muslims for these crimes.
That's the very least people should expect of themselves.
But we all should be relieved that the basic principles of natural justice and common decency remain impervious, for now, to the ravings of Donald Trump.
In some ways, urban life will have to change. Like anyone diagnosed with diabetes, city- dwellers will have to adapt to alleviate the symptoms.
Security will become more rigorous, armed police more visible, queues for public events more tiresome, but the changes will be constricted to inconvenience so long as people hold their nerve.
This won't be easy. As I write this, my 20-year-old son pops his head round the door to say he's thinking of going to Camden Market or a gallery near Leicester Square tube station.
He notices the involuntary grimace, and though I quickly insist that a grown man shouldn't change his plans to assuage a neurotic father, he sweetly decides to take a book to a local park instead.
Every parent, every child, every partner will fret a bit more than usual about those they love from now on.
Some, but very few, will have their worst fears realised.
But unless the UK succumbs to a mass collective failure of nerve, as it never did during the Blitz, cities will retain their essential freedoms.
That won't be as a deliberate rebuke to potential terrorists whose willingness to die puts them beyond caring.
It will be because this is what people with incurable but manageable conditions do. They take every sensible precaution, dwell on the disease as little as necessary and get on with the messy business of living as well and pleasurably as they can.