Taking it on trust

Seeing and believing the aerial photographs of Iraq.

Ever since the earliest use of illustration in a scientific text, we have been asked to take a great deal on trust. Whether recording data or placing us more literally as a surrogate witness to what something looks like, the author is proposing a contract with the reader. When an accomplished illustrator — and no one was more accomplished than Leonardo da Vinci — depicts a unicorn, we have a natural tendency to believe our eyes. Indeed, for a Renaissance spectator, a convincing unicorn was more believable than a giraffe. In our age of computer-processed images, we know that undetectable manipulation is possible, but our perceptual system is designed to collaborate with something that looks real.

Credit: PA

Modern science has generated a body of images of the unseeable, rather than the unseen. They demand that we trust the technological means of generation and accept the interpretative framework of expert analysers. The showing of X-rays to patients is a case in point. When a women is shown a scan of her breast, and the surgeon points to the ominous patch, she is expected to see that “there is something there”, and follow the doctor as he or she indicates that the lump is benign or malignant.

The aerial 'intelligence' photographs of Iraq used by Colin Powell at the United Nations, and subsequently published in a dossier by the British government, fall very much into this category of technological images that depend on expert intervention to transform seeing into believing.

What is captioned in the British dossier as “A photograph of a 'presidential site' or what have been called 'palaces'” provides a typical example (above). A hazy aerial view shows a grey patchwork of roads, railways, plots of land and buildings. The key points have been enhanced in black to define the boundary of the site and the complexes of buildings. To give a sense of scale, a white insert provides dramatic comparison with the “total area taken by Buckingham Palace and its grounds”. Presumably a comparably scaled plan of the much larger Windsor Castle, complete with its Great Park and assorted buildings, would not have done the job as well.

The nature of the image, which we implicitly know to have been garnered through the most advanced means available, invites us to take it as providing concrete evidence of what was happening in Iraq. 'Evidence' was an extremely heavily used word in the debates leading up to the invasion of Iraq and in the aftermath of the conquest. The models of 'information' (another widely used term) and of 'proof' used in the public debates have been derived almost exclusively from the style and terminology of modern science and technology. We are asked to rely on the expert interpretation of such images provided by the intelligence services to the leaders who make the fateful decisions.

Those of us who use visual evidence in academic research should not automatically feel superior to politicians. When, as a sometime art historian, I draw my students into looking at something my way, I am setting up a contract of trust. I used to demonstrate to my senior students that a drawing by Michelangelo was 'obviously' a forgery — even though it was in fact an authentic drawing with an immaculate history.

Scientists who draw clarifying outlines on indistinct pictures, insert meaningful arrows on technologically generated images, or produce line transcriptions of salient features, are asking readers to believe not only that they are honest but also that their expertise really does allow them to see something on behalf of those not endowed with such insight. It is a burden of responsibility that we would do well to remember.