This exhibition may claim to reveal the real Van Gogh through his letters, but what of the Sunflowers, the Self-Portrait With Bandaged Ear, oh, and Starry Night, with its roiling night sky and dark, mysterious cypress tree? What even of the dizzying Night Café, with its migraine-inducing electric lamps, its violent clash of reds and greens and the walls that threaten to collapse inwards, as if the painter had been hitting the absinthe all night?

When we look at still images of moving figures what we see is not exclusively determined by what is in front of our eyes but what we already know about the world. If we stopped to think about this, it would seem obvious. We would know, for instance, that the putti who are so joyously leaping, dancing and bounding about in Donatello’s static frieze Cantoria would make little sense to us if we didn’t already know what such static postures implied: still images of moving figures can only come alive in the imagination when we have some understanding of how living bodies move, and of what comes before and after.

The latest official royal portrait, and the first painted portrait featuring the Princes William and Harry, hangs in a small room at the National Portrait Gallery among a selection of royal portraits of the Windsors. There’s the rather quirky one of the Queen Mother, painted in 1989 by Alison Watt, an artist who sought to capture her sitter “as ordinary as possible”. What our attention seems most drawn to is the china cup turned upside down on the arm of the Queen Mother’s armchair. Eh?

Walk into the gaping mouth of the metal container featured in Miroslaw Balka’s installation at Tate Modern’s Turbine Hall and you are plunged into a disorientating darkness. Unnerved, you shuffle forward, passing and perhaps finding comfort in the ghostly presence of other limbs, other bodies which are also shuffling uncertainly, all awareness of spatial relationships denied in the enveloping blackness.

Perhaps we think we’ve got the whole thing more or less sewn up in the nurture versus nature debate. DNA profiling, gene studies, twin studies, inherited traits - this is the stuff we read about almost daily and it is all meant to tell us who we are. At any rate we seem to live in a culture obsessed with genealogy, which is perhaps as much to do with living as atomised units as it to do with the latest research about genes, or what used to be called heredity.

If Andrew Graham-Dixon's arts career ever goes belly-up, there is surely a microphone with his name on it at Radio 4, so warm and confident and trustworthy is his voice. Judging, however, by his new three-part programme on BBC Four, The Art of Russia, there is no chance of this happening soon.

We watch and listen simultaneously so much today that it hardly seems blasphemous for a superlative pianist to decide to conceive an evening of piano music plus video installation. Leif Ove Andsnes has doubts about the transmittability of classical music to a general audience today - he calls the status quo into question, and he may be right. So he turned a concert programme into a video show, focusing on Musorgky’s Pictures at an Exhibition and Schumann’s Kinderszenen, to which would be set a visual installation around him and his piano.