People are always telling me I'm opinionated. Personally, I think that's just their opinion.
A friend was reminiscing the other day about a prof back at business school who claimed he (my friend) didn't have the right to an opinion about some business question because he'd never had any work experience.
This (in my opinion) is an entirely illogical point of view. On the contrary, I would argue that all opinion deals with things that we haven't experienced or don't know about. Whatever you know for certain / can prove objectively is not opinion - it's fact. It's precisely what you haven't experienced / known that remains in the realm of opinion.
To understand this better, consider first what the professor really means when he says he 'knows' what the real world is like. Has he worked for every organisation in the world? Is he currently working for a business firm? What he really means when he says he knows about business organisations is that he knows about a handful of organisations that he personally has worked with at a specific point of time. However, every organisation is different and organisations change over time, so it's entirely possible that all the past experience he has is completely irrelevant now. In fact, learning theorists would argue that by using his limited experience to theorise about the world, the professor may actually be doing himself a disservice. Research has shown that people with limited experience have a tendency to blindly apply learnings from these settings to other situations where they may not be relevant. As a result, they do more poorly than those who come in with no pre-conceived notions*. A little learning really is a dangerous thing.
But there is a larger issue here - one that deals with the very nature of truth. What do we mean when we say something is true? Karl Popper, building off the work of Hume, argues that the continuity of truth is an illusion - that we cannot objectively know anything about the future from what we have experienced in the past. We may believe that gravity will still operate tomorrow, because it is our experience that it has operated day after day for centuries now - but we cannot prove that this will be so. As Heraclitus would say, you cannot step into the same river twice. Popper therefore concludes that we cannot scientifically claim that anything is true - at best we can only claim that it has not been proved false yet.
A parallel arguments applies to objects and situations. The key point here is that all categories are creations of the mind and therefore opinions. What do we mean, for instance, when we say that two pens are identical? What we really mean is that within the limits of our perception we are unable to tell them apart. Yet in actual fact two 'identical' pens are actually completely seperate entities - made up of separate particles of matter - which have nothing to do with each other except that we happen to have characterised them along dimensions of our own choosing as identical. Existence (or being) is the only 'fact' - everything else is merely opinion**.
People will argue that there is such a thing as informed opinion - but what does this mean exactly? Only that in our opinion, there are certain sources of information that can be trusted / that make sense. I remember attending a Bible reading once (don't ask - I got dragged there by my then girlfriend) where this young woman told me that what she loved about the Bible was that it was all completely true. So what to me is merely opinion (and fairly quaint opinion at that) is to her objective fact. It follows that all truth, all objectivity, is nothing more than a collective delusion. The whole world is opinion - it's just that whatever everyone (or almost everyone) believes is a special class of opinion that we call truth***. All empirical reality is only triangulation.
It always amuses me, therefore when people say things like, "that's just your opinion, just because you think so doesn't make it true" (which is probably what you, dear reader, are thinking about this whole theory right about now). If you really eliminate all opinion, all we are left with is feeling (and undefined feelings at that - the moment you tried putting them into words they would cease to become facts - statements like "I love you", for instance, are merely matters of opinion). And that's a world we could hardly survive in for long (although, of course, the idea that we should survive is only really an opinion by itself).
* For research on this in an organisation setting - see Haleblian and Finkelstein (1999), 'The Influence of Organisational Acquisition Experience on Acquisition Performance', Administrative Science Quarterly, where the authors find that prior experience of the acquirer is negatively related to acquisition performance; and Tushman & Anderson's seminal 1986 paper 'Technological Discontinuities and Organisational environments' where the authors argue that radical change will tend to come from new entrants who are not constrained by prior learning
**For a more detailed (and much, much better written) treatment of this idea see Sartre: Nausea (extract here) and Being and Nothingness.
***As an aside, the notion of applying democratic notions to truth is fairly ridiculous. Majority opinion is usually the worst barometer of truth, partly because most people do not think clearly and partly because majority opinion represents what is comfortable or convenient to believe. See, for instance Ibsen's An Enemy of the People (e-text here)