Tom Sutcliffe: From William Hogarth to Martin Amis, it's hard to resist an amoral monster

My question this week: which did Hogarth enjoy drawing more – Gin Lane or Beer Street? Or to put it a different way, which panel do you think he drew first?

Which part of that famous double image was the fun bit and which the follow-up spadework, required to make the moral contrast work? It's really not a difficult one this, I think. You just have to ask yourself where your own eye first travels. And it seems obvious to me that it's to Gin Lane, with its vista of human depravity. In Beer Street, everything – apart from the pawnbroker down on his luck – is seemly and meet. It's a scene of industry and plenty. And it's just a bit dull. By contrast, Gin Lane is a vision of moral ruin. And yet that's the picture we're drawn to and – surely – the picture that Hogarth most relished working on.

I found myself thinking about this while reading Lionel Asbo, Martin Amis's latest novel. On Radio 4's Today programme, he suggested that it is a Dickensian exercise in social observation (or at least that Dickens was his admired model). But it is also quite Hogarthian in some ways – a doubled study of divergent fates rather in the manner of Hogarth's didactic series Industry and Idleness, which contrast the fate of two different apprentices. In Amis's case, the industrious apprentice is Desmond Pepperdine, a young orphan who raises himself by reading, and the idle 'prentice is his Uncle Lionel – an inner-city grotesque who at one point explicitly excoriates the idea of learning anything in life.

And if you ask yourself a similar question about Amis and the creation of his novel – which character did he enjoy writing more? – I think you come up with a similar answer. Desmond may be the moral centre of the book, the character who gives it heart, but you're never sorry when Lionel lurches into the room, steam rising gently from his swart body. And though this might be the projection of a reader's interest, I think Amis's prose also brightens when he arrives. It isn't really surprising. Just as Hogarth would have sensed the difference between drawing a conventionally pretty housemaid in Beer Lane and the gin-addled slattern who visually echoes her, Amis responds to the greater liberty for invention. Beauty has its rules and its conventions. Ugliness – moral or physical – takes off the brakes.

Any caricaturist, of course, has a professional dependency on the grotesque. As one latter-day Hogarthian, the cartoonist Martin Rowson, put it when I asked him about the issue: "All satirists are there to lower the tone." He also confirmed the tendency for caricaturists to become infatuated with their monsters.

But Amis's difficulty with this effect in his novel is rather different to that of Hogarth, I think, because it undermines the very moral case he is making. You can be fascinated by Hogarth's vision of drunken fecklessness without being drunk and out of it yourself. The mind probes the jagged edge of the worst thing imaginable – dropping your baby to its death – but you are never really implicated in that atrocious loss of control.

That's less true of Lionel Asbo. The book is partly about the perversion of values that holds celebrity (and notoriety) at a higher price than actual achievement. But it also effectively requires us to respond with a tabloid reader's avidity for base gossip. What keeps us reading is the desire for something worse to happen, for the story to take a darker twist. Without giving anything away, I think Amis's plot eventually rebukes that appetite in us. But his book wouldn't work at all if it didn't feed it first. He implicitly asks, in dismayed tones, why it is that we've become so obsessed with the badly behaved and the self-indulgent. And he answers the question with his monstrous hero.

A change of tone, but is it Bardic?

Cyril Nri, who plays Cassius in the new RSC production of Julius Caesar, pictured, gets more than usual out of his line predicting Caesar's death will be "acted o'er/In states unborn and accents yet unknown" – because he delivers it in an African accent.

The setting, a post-colonial African state, works well, but I did wonder about the vocal costuming. In the 1980s, Michael Rudman's Caribbean Measure for Measure worked beautifully – something about the cadences of West Indian English. I was less sure about the marriage here, if only because an African accent often breaks a word up into syllables of equally weighted stress, which can run against Shakespeare's metre.

Advice to a struggling artist

Advice to young artists: if in doubt, repeat with variation. And if you don't think it works go and see Haunch of Venison's show of photo pieces by Nancy Holt, many of which feature grid-like arrangements of photographs.

They offer a neat demonstration of the way in which a collection of similar images is almost always more than the sum of its parts.

One photograph of a derelict western grave? Just a tourist snapshot. Sixty photographs of western graves, printed on archival rag paper? A haunting meditation on mortality and impermanence.

One straggly pine tree? A dull picture. Forty-eight different straggly pine trees all in the same format? An interrogation of landscape traditions.

The method is not absolutely infallible, but it is definitely worth trying if you're in trouble.