Colin Tudge puts the 17th-century Dutch Flower Paintings at Dulwich Art Gallery into a scientific context and explains why today's blooms look so very different
As an age of science, the 17th century was at least as exciting as the present - indeed in its novelty it probably stirred the pots of received belief more deeply. Galileo Galilei and Isaac Newton established physics and in biology, John Ray of England modestly set out to describe all living things (and managed to list 18,600 species of plants) while the Dutch linen draper Anton van Leeuwenhoek, peering through single lenses like grains of sand, discovered protozoa in rainwater and spermatozoa in the spontaneous ejaculate of a man with gonorrhoea. Leeuwenhock's "little animalcules" launched the Dutch science of microbiology. To its credit, the newly established Royal Society acknowledged his brilliance and allowed him to submit his reports in Dutch since, very reasonably, he felt that life was too short to learn Latin. Modern scientists might similarly benefit from a bracing dose of the vernacular.

In those innocent days science was called "natural philosophy" and mingled unselfconsciously with other ways of looking at the world so Newton and Ray in particular were primarily theologians and saw their musings not as a challenge to God but as a tribute, engaging the brains that he had endowed them with to explore his works and ideas. For them, natural philosophy was not the blasphemy that science has later been perceived to be but the precise opposite.

In short, science - natural philosophy - mattered in the 17th century, not simply in retrospect but to the people of the time. It was part of the mood. We have lost sight of that only because most modern historians have not been educated to see it. Nothing that happened in the 17th century can properly be construed without a feeling for the new perception: that nature could be understood; that the enterprise of understanding was terrifying in its scope and in what it might reveal; and also, in that merchant age, the hard-headed realisation that what could be understood might also profitably be controlled. You can feel these ideas at work - the naive, excited new appreciation of nature and the accordant exploitation of it - in the exhibition of 17th-century Dutch Flower Painting, at the Dulwich Art Gallery in South London until Spetember 29.

Take, for example, this glorious Vase of Flowers by Jan Breughel - one of the Breughel dynasty which was, as Paul Taylor record in his excellent notes, "to the history of painting what the Bachs are to music ... a family of extraordinary talent". (In fact Jan was the son of the great Pieter the Elder and was not so much Dutch as Flemish although, says Taylor, he had a tremendous influence on the whole genre, not least through his pupil Daniel Seghers.) The freedom and dash of this technique are obvious but so too is the precision. The botany is meticulous to the last papery bract (apart from some compression of time, as flowers of different seasons bloom side by side); indeed such art as this grew from botanical illustration which had long been a serious business, given the interest in medicinal herbs.

Appropriately, then, the Dulwich exhibition also includes 16th-century illustrations of superb accuracy and craftsmanship, each of which is accompanied by a description in Latin. Often, to save time and space the Latin descriptions were reduced to a couple of words. 200 years later, in 18th-century Sweden, Carolus Linnaeus converted the shorthand of his predecessors into the universal system of nomenclature that is with us still, whereby each species is given two Latinate names - the first generic and the second specific, as in solanum tuberosum (the potato) and homo sapiens (the human being). At Dulwich you can see the prototype notes that gave Linnaeus his great idea.

In Breughel's painting is a host of insects - which indeed feature in many of the paintings, together with toads, lizards, snakes, and the occasional snail. What insect would be allowed in a modern bouquet? Yet Breughel painted them as lovingly as the jewels that he shows to the bottom right of the picture and it surely is not fanciful to suggest that he rated their God-given beauty just as highly. We have lost that scale of values, paying fortunes for the one and wiping out the other with organophosphates. Other Dutch artists clearly delighted in the insects' depredations, including the deeply paranoid but wonderfully perceptive Simon Verelst, who painted the chewed, senescent leaves of roses as delicately as lace; ruins, after all, can be instructive as well as intriguing.

Yet there is an irony in all this. The 17th-century perception of natural philosophy was on the one hand quasi-mystical but on the other utilitarian; they expected science to deliver, to make the world more amenable. To some extent it did; the new astronomy, for example, improved the art of navigation just as its sponsors hoped it would. But in the main - and here is a lesson for post-That-cherite governments - the material rewards of science can be unconscionably slow in coming. Only the pleasure is immediate.

Take tulips. Together with anemones and crocuses and other smooth-petalled exotics, were brought to Europe in the 16th century from the Levant, and in 17th-century Holland they became an obsession. Fortunes changed hands for single bulbs - in one case, the equivalent of pounds 250,000 today. But what is intriguing about the tulips that Breughel has painted is how much they varied and how far they differ from their wild counterparts. In other words, Middle-Eastern horticulturalists had already bred them in a score of whimsical ways even before the Dutch got their hands on them and began their own hybridisations.

But the science that underpins plant breeding is that of genetics, and genetics was not even on the agenda until the 1860s when Gregor Mendel began to look closely at garden peas, and since Mendel's work was promptly forgotten for a few decades, genetics did not become a serious discipline until the 20th century. In other words, huge and critical advances in plant breeding were made long before there was any science at all relevant to the task. 'Twas ever thus.

Science in recent decades has given rise to technologies (of the kind known as "hi-tech") but technology in general had been altering the world for tens of thousands of years before science existed. Indeed, science has ridden on the back of technology much more than the reverse is true. Almost certainly, it never occurred to the creators of the windmills that transformed the economy of the Middle Ages that they needed laws of aerodynamics. The laws of thermodynamics emerged from contemplation of steam engines, which were built without their benefit. Mendel was able to find patterns in the inheritance of domestic peas because centuries of craftsmen and women had already produced cultivars that behaved tidily. Newton said that if he saw further than others it was because he stood on the shoulders of giants, and this was no less true of Mendel; and among Mendel's giants were the Dutch horticulturalists. Science in general is a Johnny-come- lately in the human attempt to alter nature and although the science of genetics is now increasing the efficiency of plant breeding well beyond the recognition of the 17th century, it has in truth been a very late comer indeed.

One final twist. Most tulips in Breughel's painting, indeed most in the exhibition, are striped. The Dutch loved stripes. The stripes in tulips, however, are caused by a virus - which modern horticulturalists have been keen to eliminate - in the bulbs that works by suppressing the natural red pigment, so that only a few streaks are left. Desirable varieties of plants are propagated asexually to produce offspring that are genetically identical and collectively form a clone. Tulips can be cloned by taking bulblets from the base. But the virus is the joker, spoiling the uniformity of the clone - or, perhaps we should say, ensuring that each bloom is unique, and there is nothing quite so seductive as an exclusive.

As Taylor comments, nobody in the 17th century had any conception of viruses. They were understood only in the 20th century, more than two centuries down the track from Leeuwenhoek's first discovery of sub-visible life. The nice point is that they are parasites which operate by manipulating the genes of their host. They are, in fact nature's own genetic engineers; and are commonly employed by modern breeders to ferry selected genes into target species. Thus by their inadvertent encouragement of viruses, the Dutch connoisseurs of tulips anticipated the highest of today's biotechnologies. It is not quite true that there is nothing new under the sun. But it is true that precious little is without precedent.

Colin Tudge is a Research Fellow at the Centre for Philosophy at the London School of Economics. His latest book, 'The Day Before Yesterday', will soon be available in paperback from Pimlico.