Perception isn't what it used to be, the meaning of the word having turned inside out. Once, perception was, according to my old-fashioned dictionary, "recognition by the senses ... of some external object or phenomenon", writes John Waters
To perceive something was to be aware of it. If it didn't exist, you couldn't perceive it: a false impression is not a perception. Nowadays, to perceive something is to believe it to exist, even if it doesn't. What we call perception is actually misperception.
So it is with the Transparency International Corruption Perception Index, published last week: Ireland has "slumped" from 11th to 19th in the chart of "least corrupt countries", although we've rallied somewhat since 2002, when we fell for the first time out of the top 20, coming in at 23. When you read the small print you discover that - as in fairness it does say on the tin - we are talking about "perception", though not in the dictionary sense.
This survey tells us nothing reliable about corruption. Neither does it tell us that we are becoming more aware of corruption that is going on. What it tells us about is the impression we have of the amount of corruption that is going on; and this, it seems, is almost entirely dictated by the tribunals and the way they are covered in the media, which in turn may reflect not the true seriousness of the situation but the opportunistic political advantage such "perceptions" provide to certain interests.
When there is a lot of tribunal activity, I perceive, our "perception" of corruption increases, whereas when the tribunals go into closed conclave or intermittently recede in public favour, our "perception" of corruption decreases in proportion.
This is a bit like calculating the level of sin in a parish on the basis of a count of confessional boxes.
Another startling indicator of the gap between what is going on and what we think is going on is the recent study of the level of conflict in the world in the past 60 years. The Human Security Report, published by a team from the University of British Columbia, debunks the conventional belief that the world is becoming less safe.
The impressions, to be gleaned from even a cursory reading of any daily newspaper, that war is more prevalent than ever, that genocide is on the rise and that terrorism represents the greatest threat to humanity, are all, the authors declare, either suspect or "demonstrably false".
They set out a different picture: armed conflicts reduced by 40 per cent in the past decade, worldwide arms trading in serious decline (down one-third between 1990 and 2003) and international refugees cut by half in the same period.
Not only has the number of wars been cut (largely as a result of the ending of the cold war and the peacekeeping efforts of the UN), but casualty rates are reducing dramatically also.
A half century ago, the average conflict killed 38,000 people; now the average is in three figures. Even the war in Iraq, which mostly occurred after the survey period, does not alter the picture significantly.
What has happened to "perception" is not just about declining standards of English: it is also a symptom of a profound shift in media culture.
Once, the media traded in facts, opinion and analysis. Nowadays, competing with one another at an ever more ferocious rate, media seek to sell us material to provoke an emotional reaction. They urge us to mistrust or despise political leaders, to live in fear of fatal disease, to become incandescent about how corrupt we are becoming. Fear and anger sell newspapers and make us turn on our TVs.
Hence, when it comes to what might become a legitimate concern, we find ourselves without a compass. Is there a real threat to human populations from avian flu? We have no way of knowing, because, whether there is or not, the channels of information have a vested interest in convincing us that there is.
Apprehension sells. For several weeks, the media have been working assiduously to give the impression that, within a short time, an epidemic of bird flu will wipe out tens of thousands of people.
When you look more closely at the detail, you find that the solicited prognostications of "experts" are studded around with qualifiers like "might", "could and "if". All we are really being told is that "if" the virus creates a human strain, it "might" result in deaths and these "could" run into thousands. But the size of the headlines or the excited tone of newsreaders does nothing to integrate these caveats into the message.
A couple of years ago, we were told that a disease called Sars would wipe out half of Europe, but nowadays nobody mentions Sars at all. In a year or two, "bird flu" may be but a distant memory, and nobody in the media will be called to account for the hype we are enduring now. Or, in the alternative, many of us will have died from a disease we failed to take seriously enough because we didn't believe the media headlines.