Blurred snaps of our sense of self

In this, her latest work, Marina Warner embarks on the charting of the genealogy of Western concepts of the self, the metaphors of its visible and invisible aspects and powers and the interaction between technologies of representation and their changing content. As befits its subject, this is a vast, wandering book of unsure focus. While occasionally fuzzy and verbose, it is only intermittently overwhelmed by postmodern pidgin - annoyingly at crucial points - yet still passes through many places of real interest that will fascinate students of culture, history, painting and science, as well as the more general reader.

The work is divided into ten sections only approximately moving forwards in time: "Wax", "Air", "Clouds", "Light", "Shadow", "Mirror", "Ghost", "Ether", "Ectoplasm" and "Film". And each is internally subdivided again.

Wax as a way of thinking about spirit and flesh, form and dissolution leads on to death masks, Renaissance anatomical bodies and wax models that simulated life through clockwork implants. Air introduces the notion of the Breath of Life, music and the harmony of the spheres.

Within sections, Warner allows herself great liberty in following her nose, so that Gunther von Hagens jostles Madame Tussaud and contemporary artists while themes snake in and out of various sections: motion as the mark of life; incorruption as a measure of virtue; formless matter as the attempt to find a material metaphor for the incarnation for spirit itself.

There is a formidable amount of meat in these sections, in every sense, and in each are embedded little jewel-like essays that would stand in their own right regardless of any greater scheme, so that the general effect is rather like that of reading through a first-class encyclopedia.

Probably the most powerful sections are those dealing with the impact of the camera and the revolution in late 19th-century physics, whereby the sudden endless foison of particles, waves and invisible gases, undetectable to unaided human senses, offer new ways of thinking about mind and spirit, life and death. Most striking is the way that scientific positivism is not opposable to Romantic fancy in the exploration of other realms of existence and powers of the mind, since many of the leading figures engaged in the serious study of spiritualism, fairies and speaking in tongues are eminent scientists and establishment figures.

The weakest sections are those where Warner strays outside the familiar tradition of the West. Thus, there is a long discussion of the notion that non-Western peoples' thought that the camera might "steal their souls".

Warner is correct in discounting this as an accurate rendering of native intuition. But she is quite wrong to discount the belief in the fatal effect of portraiture. In cultures where the only representations of humans made were funerary images, such beliefs are perfectly natural (comparable to our own symmetric reluctance to take photographs at funerals) and has to be seen, moreover, as one of the attributes of photography being classed as locally a male technology. Here, Warner has wandered away from spirits and souls into the huge area of local notions of creativity, and it is striking that one so sensitive to issues of gender should neglect to point out that in many parts of the world females, more particularly fertile females, should not be involved in the production of simulacra as it would compromise their natural gift of childbearing. African villagers will provide quite explicit accounts of men producing art because they cannot produce babies that Freud would have regarded as his own original thoughts.

Post-menopausal women, of course, "become men" and may be fully artistically active. Similar problems cluster around her later discussions of zombies.

To make the book work at all, Warner is obliged to embrace an unusual theory of the relation between form and meaning derived from Henri Focillon, who sought to allow generation of forms autonomously with meaning both contingent and conditioned. This permits a view of language that is resistantly coherent, not simply cluttered with the debris of abandoned systems. The analytical result is a touching faith in the explanatory power of etymology, an overreliance on the forms of art as a route to cultural meanings and, in later sections, a desperate will to gurudom where technology does not just provide new ways of thinking about old enigmas but must lead to the revolutionary transformation of notions of self and have sweeping political consequences. Unfortunately, for all the words and images that boil within these covers, we are offered no convincing picture of what such a revolutionised self would look like.

Nigel Barley is a writer and anthropologist. He was formerly assistant keeper at the British Museum.