Howard Jacobson: It's much better you don't know my secrets

I don't know whether one can trust the person doing the counting – in the context it would be foolish to trust anybody – but apparently Wikileaks is responsible for leaking 251,287 US embassy secrets this time around. Sounds a lot, but is it really that many? I reckon I kept twice that number of secrets from my parents between the age of 10 and 17 and I'm not a country.

So how many of those should have been leaked to my family by public-spirited neighbours, teachers, doctors, assistants at the local pie shop, suppliers of chest expanders and posing pouches, proprietors of record shops – "Your sick son has bought five Mario Lanza LPs this week" – purveyors of soft porn (not that it seemed soft to me), bouncers, cocktail waitresses (don't ask), women of the night (you can ask but I won't tell), indeed whoever I made contact with, since it would have been abundantly obvious to every one of them that I was a boy with 251,287 secrets on his conscience?

Answer that and you have solved one of the major moral conundrums of our time. What are we free to say, what are we not? What is it in our interest to know, what is it not? When should a secret stay a secret?

In the case of the heaving adolescent store-house of red-faced concealment that was me, the answer would have been an unequivocal "It's better you don't ever find out what's in there!". Better for me, better for them, better for humanity. Better for the English Novel, you could add – in so far as I can be said to have made a contribution to it – given that the habit of hoarding secrets, of confiding only in yourself, of distorting the truth, to say nothing of finding yourself exceptionally disgusting and not suffering the disillusion that comes with the discovery that you are no more disgusting than everybody else, will more surely make a writer of prose fiction out of you than all the creative writing courses in the country rolled together.

Though a scrawny weakling of a boy (for those chest expanders never worked) is not a Charles Atlas super power, and though what my parents needed or didn't need to know is not quite what the populace of a world fixated on democracy feels it needs to know, some of the lessons remain the same, the first being that we can believe in an "open society" all we like, there will always be necessary limitations to it. And once you grant that, it is difficult to promote freedom of information as a philosophical principle. This is as it should be. No invariable principle is worth a hill of beans. God is good? Only sometimes. Men must be free? In certain circumstances. Never tell a lie? Depends who you're telling it to. "Context is everything in the free-speech debate," wrote John Kampfner in this newspaper last week. "Risk to life is an undeniable caveat."

But who judges what constitutes a risk to life? Whose life, at any time, are we we talking about? And once the saving of life is admitted to trump all other considerations, what happens to our stand, say, on employing torture to extract life-saving information? "Torture doesn't work," say those who oppose it, but that dodges the ethical question. What if we devise a torture that does?

Thus with our entitlement to know. Sometimes we have such an entitlement, sometimes we don't. And when that sometimes is can only be decided empirically. Myself, I think the more things that are kept secret the better, not least as we can guess most of them for ourselves. Did we really need WikiLeaks to tell us that those who govern us chatter and are suspicious of the chatter of others? That American politicians don't much like English politicians hardly comes as a surprise. Ditto what they think about Putin or Sarkozy. Ditto, once Wikileaks manages to nick a memory stick from Russia and France, what Putin and Sarkozy will turn out to think of us. So Saudi Arabia would like someone else to sort out Iran. Who doesn't want someone else to sort out Iran? And as for the Americans having views on the "inappropriate" behaviour of certain members of our Royal Family, how do they differ significantly from ours?

If I didn't want my parents to know my secrets I didn't want to know theirs. My friends felt the same. We didn't suppose we were the offspring of angels. They were adults and did adult things: cheated, lied, gossiped, mistrusted one another and in the process made asses of themselves. Or at least, we hoped they did. We hoped they lived full lives.

Similarly, I hope that America is keeping tabs on everybody, treats every foe and ally with suspicion, assumes the world to be a dangerous and treacherous place, and is impressed by no one. I would rather the worldly-wise are in charge than the gullible. It won't be the worldly who will bring life to an end – they love it too much. It will be the idealistic.

But if you are going to be cynical it behoves you to do it well. Keep your secrets secret. No point knowing the world to be full of thieves if you go leaving your wallet everywhere.

To the degree, then, that Wikileaks exposes a failure to protect necessary confidentiality, it does a laudable job. Thereafter, its work is contemptible. If there is a difference between Wikileaks and a hostile intelligence agency I am unable to see it. Where authority is concerned, we live, of course, in sentimental times. We take it as read that Western governments betray their people, and that every large corporation – particularly when it's American – is corrupt. From which it follows that every whistleblower is a hero. People who otherwise have no interest whatsoever in Dr Johnson know that he called patriotism the last refuge of the scoundrel; but when patriotism is gone out of fashion the last refuge of the scoundrel is, in fact, disloyalty. Defection became all the rage among intellectuals who saw Communist Russia as a Utopia, and though the location of Utopia has changed, the habit of defecting hasn't. The new Utopia, you could say, now that loyalty is a suspect concept, is the act of defecting itself.

But there is such a thing as an enemy. And there is such a thing as aiding and abetting him, and making him strong at our expense. Openness is a fine ideal, but it is criminal folly to embrace it unconditionally. Unconditionally revelling in the right to know is not a lot of use if others unconditionally employ that knowledge to destroy us.