R. Hooykaas’s research while affiliated with Netherlands Institute for Space Research and other places

An ‘Experiment’ is a deliberate act which aims at knowledge of nature and power over nature. In medieval Latin, however, ‘experimentatum est’ can also refer to a mere rather passive observation; in modern French ‘expérience’ is a word for experience in general as well as for experimentation.

When the University of St Andrews was founded in 1410 its first rector was Lawrence of Lindores (circa 1437). All historians of the university mention that he was also ‘Inquisitor of heretical pravity’ — the main inquisitor of the kingdom of Scotland— and that, as such, one of his unattractive features was his zeal in bringing Lollards to the stake.1 If the prior of St Mary’s had had his way there would have been even more victims, for he wrote to Lawrence an admonitory letter (1418) richly larded with quotations from Scripture and from pious writers, chiding him for his laxity and ominously imputing to him a tendency to heresy himself.2

Hypotheses and the theories built upon them are of two main types:1) they may be intended as constructs conformable with physical reality; 2) they may be only conventions which need not be true but which are useful in describing and predicting facts. Both types demand that hypotheses and theories should be as simple as possible; the latter for methodological reasons (theories should be as simple as possible); the former for ontological reasons (nature is believed to be simple and economical in its means). In the long run the two types of hypotheses and theories frequently converge.

After Paracelsus qualitative explanations in chemistry lost ground because of the development of corpuscularian theories. These theories, so warmly welcomed at the beginning of the 17th century that they were called ‘the key to almost all natural science’,1 turned out however to be rather sterile. They interpreted the phenomena by using notions and terms of their own, but — except in some very limited fields — they could not predict new phenomena. In those cases, that where the compound was separated by heating into two other substances, it did seem that these already existed before the separation, in particular if it was possible to reunite them into the original compound. Ammonia [NH3] and ‘spirit of salt’ [HCl] formed ‘sal ammoniacum’ [NH4Cl], and the reverse could also be effected by heating the latter compound.2 Similarly when Angelo Sala (1617) dissected copper vitriol [CuSO4×5H2O] into copper-ash [CuO], vitriolic acid [SO3] and water [H2O] and synthesized it again from these constituents, the conclusion seemed justified that, in spite of the temporary loss of their qualities, small particles of copper and vitriolic ‘spirit’ were hidden in copper vitriol. The presence of finely divided copper in a solution of copper vitriol in water was proved by putting a piece of iron in the solution: copper then precipitated on the iron.

It has been claimed that Natural Theology has been an incentive to the scientific investigation of nature and that, conversely, this investigation yields arguments in favour of it. Certainly some of the greatest scientists (Kepler, Boyle, Newton, Hutton) used their discipline to point to the power, wisdom and goodness of the Creator of all things.

Copernicus’ great work De Revolutionibus Orbium Caelestium was published in 1543. Today it is widely accepted that this book, On the Revolutions of the Heavenly Orbs, marks the beginning of the ‘scientific revolution’: the Aristotelian Goliath was slain by the solitary Canon in remote Poland; a science based on observation triumphed over clerical dogmatism; the Earth was removed from its central position, and its human inhabitants thereby lost the privileged position accorded them by the Bible — whose authority in its turn was severely damaged. In short, with Copernicus fact triumphed over faith and fiction ...

We have contrasted scientific theories that claim to represent the reality of nature with those that are just useful fictions establishing connections between phenomena, without any claim to physical truth (chapter VIII). We now tackle a related problem — the comparing of natural products with similar ones made by human art.* In the case of chemical compounds, minerals and rocks, for instance, we could try to find out their composition by means of chemical analysis and then confirm this analysis by a synthesis out of the components. Supposing we find that human art is indeed capable of making things produced also by nature, immediately the question arises: can we find a procedure to make a natural product (e.g. sugar), minerals or rocks in the same way as nature does?

‘The nose of Cleopatra: had it been shorter, the face of the entire world would have been changed.’1 This famous aphorism of Pascal’s — all the more memorable for the pun it contains — raises a much-debated question which has its relevance for the history of science: does history inexorably run its course, determined mainly by social and economic forces describable in terms of fixed socio-historical laws or is it rather capriciously determined by contingencies like the sudden death of a prince without legitimate offspring, the murder of a prospective heir to the throne by the hand of a madman, or a natural disaster that devastates a country? A shorter nose would not only have defaced the face of Cleopatra, it could have changed the political face of the world. For Mark Antony might not have fallen in love with this last Queen of Egypt; his conflict with Caesar Octavian would then have taken a different form; the history of the Roman empire and consequently that of Western Europe might have followed a quite different course.

Aristotle’s ideas of Being and Change, of elements and compounds and of the structure of the universe had an overwhelming influence, even upon those, such as the Stoics and the Neoplatonists, who did not belong to his school of thought. In the Middle Ages all scholastic sects accepted his cosmology; later the vast majority of Renaissance philosophers, even though they were more inclined towards Platonism, would accept much of his natural philosophy and most of his astronomical system.

One of the most quoted texts in the literature of ancient astronomy and chemistry is taken from the apocryphal Book of Wisdom. It runs: God ‘has ordered all things according to measure, number and weight’,1 or, as the 15th century alchemist Thomas Norton phrased it: by Ponders right, With Number and Measure wisely sought, In which three resteth all that God has wrought.2