TO KNOW wisdom, you must first know ignorance.

So allow me to help you with the latter. I wish to discuss something I know nothing about (reader: "There's a first"). My subject is acting.

I've a fascination with actors. Haven't we all? How could we not? Most of us watch them every day of our lives.

They influence us in our looks, walks, talks, clothes and even philosophies. Well, at least their characters do.

The point baffling me is this: how is it that, in the behind-the-scenes shots you get in DVD extras, where the filming of the filming is filmed, the acting — seen in the raw — always looks so, well, rubbish?

They just look like they're saying stuff no better than a man or woman off the street could do. And it all seems so lackadaisical.

You hear them saying to the director. "And I just go over there and say this, do I?"

And they do. And that's it. And by the time it's on the screen it looks brilliant. And they get paid a fortune.

It's a piece of nonsense. I was going to say anybody can do it, but since I can't even pose properly for a still picture, I guess there must be something more intangible to acting in a film.

I'm not making a point, despite deploying the arguably controversial word "nonsense".

I'm just bewildered and wondered if you'd noticed this too. I suppose actors' charisma must interact with the lens in a chemical way. Or something.

The music will help too.

They don't even look that great in the raw, a bit common-or-garden, even with make-up, but by the time it's down on film they're all shiny and godlike.

What you need for screen-acting, it seems, is to have a face that can look potentially good or interesting, if the camera takes to you.

Theatre is different. For that, your biggest asset is a voice.

There's the whole question of emoting, of course. But, even there, I say again: when you see it filmed informally, it looks unconvincing.

Then by the time it's on screen it goes straight to your heart.

I love actors and worship them. They are, effectively, our gods.

But I confess: I have no idea what they're doing and how they do it.

And thus I have taken the first step towards wisdom.