'Mondrian and Af Klint: Forms of Life' (Tate Modern until Sept 3 2023): Life and Lifelessness

Gallery View of Hilma Af Klint, The Swan series, 1914-15

Mondrian and Af Klint: Forms of Life, currently on at Tate Modern, is not the best exhibition you'll see this year but it might just be the most seismic. You can't enter The Swan series room and not feel the bang of the canon being exploded in front of your eyes. And it's almost as hard not to utter a whimper at the later naval-gazing Mondrians, after richness of what came before. 

On paper this was an odd exhibition, and in reality it remains so. Two artists, who never met, who have really nothing in common apart from an interest in spiritualism and theosophy and a career shift from naturalism to abstraction. They aren't unique in either of these things. They both merit an exhibition in their own right. And 1900s spiritualism is a slippery enough concept to warrant its own investigation, as the 'Into the Ether' room demonstrates. So what the exhibition provides is a kind of uneasy mash-up in which the two artists are kept judiciously separate - usually on opposite sides of the room - and we are given a vaguely chronological look at both, which keeps dipping self-consciously into matters of the spirit. 

Mondrian might be the better known artist, but Af Klint is surely the draw, and arguably a braver exhibition would have been a one-woman show which contextualised her work within spiritualism whilst tackling head-on the criticism that her visual language is not art but philosophical schematics. The early rooms at the Tate establish her artistic credentials with a nicely presented wall of botanically precise flower paintings and some early impressionistic landscapes. It is less successful in explaining the pull and role of spiritualism which remains a frustratingly intangible concept, and there are sections of the exhibition where Af Klint's theosophical investigations clearly take over. A line of diagrammatic representations of world religions seems, to me, to tip over the edge into philosophy.

At its best Af Klint's art is elegant, ground-breaking, breathtaking. Her early organic-form, pastel-shaded watercolours are Art Nouveau in their elegance, reminiscent of work by the Glasgow Girls. The strongest works in her Swan series, painted 1914-15 are, in terms of scale, abstraction and sheer muscular-heft, at least a generation ahead of their time. This was when Mondrian and Malevich were inching forwards towards  Neoplasticism and Suprematism, when Kandinsky was still working on expressionist-derived Compositions. Af Klint is producing  6 ft canvases of target-forms on black. Yet the exhibition ends with The Ten, the works for which she is perhaps best known. The effort is impressive, especially up close where you can seen the paint drips and the joins and creases in the paper, but the effect is impersonal and unengaging. It is partly, I admit, personal taste: the dominant colour scheme of oranges and pinks and the quirky, almost Miroesque forms seem too light and pretty for so weighty a purpose. But the flatness of the medium also acts as a barrier to engagement. It means you leave remembering all the criticism levelled at Af Klint, rather than strengths the exhibition showed earlier.

Piet Mondrian, Dune Landscape, 1911, Kunstmuseum, The Hague

Unfortunately, the same is also true of the Mondrian half of the show. His early work is a spectacular exploration of colour, medium and emotion, from the pointillist Dune, to the loose, expressive decadence of his dying flowers, and the zingy primaries of Red Tree. Evolution remains an unforgivably weird painting, but next to it the large-scale purple and green  Dune Landscape combines deep, involving shades, with intricate geometric patterning and a profound sense of depth underlying the two-dimensional design. Mondrian's Cubist-influenced shift towards minimalism and abstraction is less clearly illustrated but the exhibition has some fine examples. The shimmering, shifting rectangles of Composition with Coloured Planes are like his dune paintings magnified and dissected, reduced to their very essence. 

With its spiritualism-driven narrative, the exhibition divorces Mondrian's Neoplasticism from both his involvement with De Stijl and from a formal exploration of abstraction. Theosophy was clearly an important motivation but it is not the sole driver, as his engagement with American culture after his emigration (which is also ignored) emphasises. The room devoted to his primary grids, which should be the high-point, feels cluttered and unsympathetic. The concept is so overfamiliar, that the works themselves need space, time and quiet. The reality of these small, introverted canvases - the nuances of grey-tinged colour, incomplete lines and subtle tonal shifts - is so much more painterly, so much less polished than one remembers. And so much more involving as a result. Yet as displayed here, I kept thinking back the rich, exuberantly-applied colour of his representational works, and wondering if spiritual equilibrium was really worth giving all that up.

The Tate's exhibition is frustrating on many levels, It is really two shows sandwiched together and the emphasis on spiritualism is unsatisfactory in both cases. Theosophy and its off-shoots were hugely influential for early twentieth century Europe, and its art. The philosophy was a driver for many artists (not just abstractionists), and it seems bizarre to belittle either its role or the art produced. We do not, afterall, dismiss Fra Angelico's San Marco frescos because they were direct expressions of his Christian faith painted to inspire monastic devotion. Forms of Life should be applauded for trying to tackle the subject, but in doing so, it unfortunately reinforces prejudices about Af Klint and takes a reductive approach towards Mondrian. There is some great art on show, but you leave with a sense of confusion and disappointment.