Jackie Wullschlager gets ready to hang her show

“Painting will always reflect your nature without mercy,” says artist Sean Scully. So does taste in painting – which is why private collectors such as Charles Saatchi become, when they show their works, public personalities. Critics, on the other hand, hover on the edges, judging, praising, blaming, but rarely putting their own choices on the line.

But for every Turner Prize or Saatchi show that we condemn, could we do better? This question rang in my ears when, on a couple of long, bright days at the end of the summer, I descended into a gloomy basement in Carlton House Terrace, settled at a trestle table with five other art-lovers, and gazed beadily, eagerly, desperately, as a human conveyor belt of students whisked before our eyes, for a few seconds each, some 2,300 paintings, drawings, photographs, sculptures. These were the open submissions for an annual event called The Discerning Eye; our task was to choose the handful – 18 in my case, less than one per cent – which would make it to the walls of our own exhibitions.

Every year The Discerning Eye, which opens at the Mall Galleries next week, appoints six pairs of “eyes” – two collectors, two critics, two artists, ranging in the past from Prince Charles and Anne Robinson to AS Byatt and Charles Saumarez Smith to Jonathan Miller and Peter Blake – to curate and hang a show comprising works by artists they have invited, and pieces chosen from open submission. There is no hiding behind a committee: each selector’s section is hung separately, each shows celebrated names alongside emerging and unknown ones.

Individual choice – rather than a panel decision – means the show is more eclectic, disparate, unpredictable and personal than the Royal Academy’s Summer Exhibition, while a brilliant caveat limiting works to no more than 20 inches in any one dimension ensures that proceedings never degenerate into Turner Prize folly and vainglory. The result is an exhibition in tune with what gallery-goers might like to own and, even, afford. Everything is for sale; prices this year range from £80 to £32,000, with a strong group of works spanning the £1,000-£5,000 bracket, and a large bargain basement.

Barbara Jackson’s ‘Transience’

How on earth did we choose them, and what do those choices reveal about us? I had feared unseemly competition, fights for the best works, slumps of indecision, but my fellow selectors – actor Peter Bowles , interior designer Laurence Llewelyn-Bowen, artists Gus Cummins and Lincoln Seligman, and Julius Bryant, keeper of word and image at the V&A – were congenial, lively company throughout. Rather, it was our different approaches that at once became comically apparent.

Peter Bowles, commuting between Carlton House Terrace and acclaimed performances in The Browning Version and Chekhov’s Swan Song, loped in as if from another world, surveyed the scene (“it takes a few minutes to get your eye in”), then unhesitatingly, charmingly, picked a selection whose meditative, mysterious tone appeared to complement those of his invited artists – William Crozier, Stephen Chambers, and his daughter Sasha Bowles, with her skilfully ambivalent, muted nursery scenes.

Gus Cummins too was quiet, quick, sure of his eye, favouring “visual poetry (not too literal), works that give clues to the artist’s thinking processes”. Julius Bryant was clearly hanging his show in his head, sometimes aloud; working habitually with words and images, he had an interest in less likely media – photography, computer or book art – and in the diversity of current genres, as well as “works that share that very English sense of humour through dry understatement”. Lincoln Seligman, most generously responsive and pluralistic of us all, ended up with 140 works by 75 artists, but was a model of chivalry when we came to battle – I owe him for Peter Edge’s evocative “San Carlo alle Quattro Fontane, Rome”, a cool interior with shadows and glazes recalling 17th-century Dutch painting.

I thought the pleasures of the open submission few and far between. Laurence Llewelyn-Bowen, by contrast, was struck by “how romantic we all are these days”. He was, he said, “quite seduced by what I felt was an extremely lyrical mindset that’s colouring art with a wonderful wistful dreaminess”. His choices – Michael Clark’s fluffy dogs, “Zucchero”, Kate Kessling’s series “Buttons for Gerhard Richter”, “Liquorice Buttons”, “Philippe Starck Ghost Buttons” – reflect his belief that “art is about telling a story and there’s absolutely nothing wrong with a story that has a happy ending”. Since my view is that painting is a tragic language, our sections offer diametrically opposed visions of art’s impetus, methods, role – exactly the sort of dialogue the show intends.

Art means many things to many people. As a critic, I am used to telling it how I think it is; showing that in a gallery, through works by the invited artists making up the bulk of my 73 exhibits, is another matter. Whom to ask? How to fix the historical moment? Which artists can produce commanding work within the small format?

Craigie Aitchison’s ‘Washing Line, Montecastelli’

The grandees of European art often say “no”, but sometimes they say “yes”, because to see old and young work together is exhilarating. The great 89-year-old Swiss-German sculptor Hans Josephsohn sent a historically important “Head” from 1955 – the most expensive work in the show – as well as more recent reclining nudes, busts and reliefs that give a powerful overview of his long engagement with the human form. His bulky figures with their scrunched, lumpy surfaces, accumulated in layers that lay bare traces of working processes, appear to come uneasily into being from chaos; turning like Giacometti’s on absence and presence, they occupy the tense, fertile terrain between figuration and abstraction at the heart of modernism.

I set these alongside innovative inheritors of that legacy, in different media and from different generations: contemplative half-abstracted forms in alabaster, onyx and limestone, rigorous but glowing with an inner luminosity, by Britain’s pre-eminent stone carver Emily Young, born in 1951; 28-year-old Shaun McDowell’s energetic, erotically charged oil stick on board all-over abstract paintings, which take the figure or nature as a starting point while responding, with daring colour harmonies and passages of intense, fine detail, to 21st-century visual overload.

I always enjoy dialogues between painting and sculpture; setting them up myself, worrying about plinths, eye levels, fragile materials, allowing works space to breathe, made me understand how difficult they are to do and gave me new respect for those emperor installationists who always get it right. Some pieces demand their own places, some must be juggled around; some dominate, others are overshadowed.

As at any gathering, you can only try to set up conversations – between, say, the austere yet lavishly sensual white porcelain of Edmund de Waal’s laquer cabinet “The Hours” and Tom Barnett’s lyrical painted plaster cubes “Silver Sculpture”, “Pink Sculpture”, “Golden Sculpture” and “Black and White Sculpture” – also a musing on time, and to my mind a four seasons quartet, their streaked, sprinkled colour and damp, encrusted surfaces suggestive of spring promise, lush summer, elegiac autumn, icy winter. Just as engagingly, Barnett’s textural, three-dimensional approach to the landscape genre finds an echo in the multimedia constructions of South African Karel Nel, whose “Stellar Masks” and “Atomic Field”, composed from 250m-year-old carboniferous dust, salt and white pigment, ponder man’s relationship to the earth, the complexity of matter, our attempts to reach for space.

I am fascinated by such reinventions of tradition. I loved, too, juxtaposing artists whom I would not expect to see together elsewhere. Eighty-three-year-old Craigie Aitchison’s pared-down screenprints – “Crucifixion and Dog” , “Tree and Poppy Montecastelli” – and 21-year-old Nathan Cash Davidson’s jewel-like, crazily titled oil on metal panels “It is disappointing but out some get rid of this teenager John Smith” and “Is to be left to the wem of chance” inspired by urban life and cyberspace, demonstrate two figurative painters, separated by 60 years, as quintessential distillers of beauty, suffering, the pathos of the absurd. When I see them, I recall the advice of Sergei Shchukin, legendary Matisse and Picasso collector: “If you feel a psychological shock in front of a painting, buy it without further ado.”

Of course, what arrests me may bore or appal you. Being a “discerning eye” gave me both a chance to play fantasy collector for a few weeks – and to be judged at last by the public display of my own taste.

‘The Discerning Eye’, Mall Galleries, London, November 12-22. Tel: +44 (0)20 7930 6844