Is anything sadder than an elephant's behind?

Thus do I mark the parabola of my maturity – when that I was and a little tiny boy I railed against the corruption of advertising, warning my parents that I would never lend my name to a product, and so not to expect me to earn them a fortune from washing powders, tins of mashed peach and rhubarb, or diapers (I couldn't then and cannot now say nappies); when I grew to man's estate I marvelled at my earlier priggishness, laughing away all compunctions, letting nothing, least of all capitalism, come between me and a good time (though still not earning a fortune for my parents); but now that I am old and grey I am back almost where I started, not hating the corruption of those who wish to sell me things exactly, but hating the triviality.

Thus do I mark the parabola of my maturity – when that I was and a little tiny boy I railed against the corruption of advertising, warning my parents that I would never lend my name to a product, and so not to expect me to earn them a fortune from washing powders, tins of mashed peach and rhubarb, or diapers (I couldn't then and cannot now say nappies); when I grew to man's estate I marvelled at my earlier priggishness, laughing away all compunctions, letting nothing, least of all capitalism, come between me and a good time (though still not earning a fortune for my parents); but now that I am old and grey I am back almost where I started, not hating the corruption of those who wish to sell me things exactly, but hating the triviality.

I have never wavered in that time in the matter of the indignity we suffer upon animals. Long before I'd heard of Stalin I thought Walt Disney the most evil man on the planet. It isn't necessary to choose: you shouldn't kill millions of your own people, and you shouldn't put dresses on elephants. But about our own bodies I was more lenient. A boy's thing, presumably. You need to see women's bodies, women aren't as willing to show you theirs as you would like them to be – especially when you're 11 and a half with boils all over your face – so you take whatever you can get.

There was, as every man my age will tell you, National Geographic, but their pictures were never entirely satisfactory. Cannibal women of the New Guinea Highlands did not look sufficiently like your cousins or your aunties to be genuinely arousing, and the fact that they were pregnant, malnourished or dying of malaria took from the pleasure of looking if you were at all sensitive. Which left only advertising – photographs of women in lingerie (I could not then and cannot now say bras), or, if you were lucky, showering behind frosted glass, or in a bath clothed to the throat in a chain-mail of soap bubbles.

Now that 40 or more years of needy boyhood are finally behind me, I can return to my default position: we are no better than the skirted elephant, we lack bodily dignity, and unlike the elephant who knows that what is being visited on him is unseemly, we don't. Take all the bums to which we are currently having to attend, Jennifer Lopez's for example, whoever Jennifer Lopez is, and those we see plastered on billboards all over the country, advertising toilet paper. Are they not dispiriting?

Let me be clear: it isn't the lewdness or intrusiveness that bothers me most; nor, in the ads, the gross association of the bottom with its functions, though I take the breaking of the tacit taboo on pollution very seriously, and believe no allusion to defecation, however tissued, should ever be made in a public place. No, what I hate about this bummery above all else – as I hated it in Disney – is its lack of gravitas.

We have lost our sense of tragedy. In literature we think tragedy is something that happens in a particular place or among a particular class – in Ireland, in the Middle East, or where the poor live. We have politicised tragedy, imagining it to be fixable. Tragedy is that to which we don't attend. Not the essential, unavoidable, upsettingness of life.

In the days before we decided that the best way to educate our children was to disinherit them, elbowing out DH Lawrence and George Eliot, and giving them Ben Elton and Toni Morrison to read instead, on the grounds that modern writers are more relevant – relevance, that last refuge of the philistine and leveller – in those long gone days when no one was ashamed to talk about the betterment of minds, a Thomas Hardy novel oozing pessimism was always de rigueur. We did The Return of the Native. Hated it and loved it by turns, but stored it in our imaginations whether we wanted to or not.

Still not a week goes by when there does not steal into my mind, prompted by one thought or another, Hardy's description of Egdon Heath, "neither ghastly, hateful, nor ugly: neither commonplace, unmeaning, nor tame; but, like man, slighted and enduring... It had a lonely face, suggesting tragical possibilities." An evocation of ineluctable sadness which is both lyrical and clumsy, like the Heath itself, and like the countenance of man which it resembles.

Pathetic fallacy, the teachers told us. The attribution of the human to the non-human. But it felt a two-way thing to me. The moor a sort of face, and the face a sort of moor. Each sad because of the other. Each having to endure.

And as with the sadness of man's front, so with the sadness of his behind.

Fun's fun, but we owe it to ourselves not to trivialise the landscape of our bodies. I except the penis. I would not myself choose to buy a ticket for Puppetry of the Penis, now showing at a theatre near you, but I acknowledge that the quicksilver preposterousness of that organ must always give rise to mirth. Our behinds, though, are another matter. Neither ghastly, hateful, nor ugly, neither commonplace, unmeaning, nor tame, they bear the gravity of our unhappy natures.

I don't know why this should be. Perhaps it's because our behinds are the last you see of us when we leave. Or perhaps they are the very fault line of our mortality. The stronger and more indestructible we seem, the more vulnerable we appear behind. Only consider the elephant. Is there anything in nature sadder than an elephant's behind?

Only our own. The last part of us you see, but also the first part of us to fall into decay. A man's chest, a woman's breasts, can go on looking magnificent until the last breath leaves the body. Rarely the behind.

A little more reverence, I say. Don't make light of what is serious. Permit us to recede with grace.