The main ideas and
procedures about how the natural world should be investigated were
established by about 1450-1500 . However, at this time physics, the
main driver of finding out about how the world works, had not yet
defined its fundamental units of thought. Its individual branches
were a scattered collection.
Sound was much
occupied with a semi- mystical arithmetic of music. Magnetism, in
spite of the stimulus of navigation, was in abeyance.
Electricity was confined to a few mysterious observations on amber
and the like. Heat was, in the main, part and parcel of alchemy.
Like biology, optics and mechanics interested the great artists. To
us, their optics is little more than geometry—than
perspective. But then both perspective and anatomical accuracy were
part of the new phase of artistic naturalism which was setting in,
with men like Botticelli (1444- 1510), Durer (1471-1528), and
Leonardo da Vinci. Such phases are recurrent in the history of art
and are commonly associated in discussions of the subject with that
very consultation of nature which is one side of the scientific
spirit.
The geometrical side
of perspective was studied by a series of artists, Brunelleschi
(1379- 1446), Leonardo, Alberti, and Durer; and this study had
important effects in mathematics and physics.
The geometry of
refraction already had a long, if intermittent, history : from
Ptolemy's experiments, through Ibn-al- Haitham (965-1020) on the
refraction of lenses and of the atmosphere, to Roger Bacon's
project for a telescope (c. 1250), By 1300 convex spectacles were
spreading, especially from the Venetian glass-works, but concave
ones were not common until the middle of the 16th century, and were
even then were rare, highly valued objects.
There was, however,
some physical, and physiological, optics as well. Leonardo studied
the eye, though he thought the liquid centre portion was the main
image maker. But the old view that vision is a matter of tentacles
coming out of, as well as of light entering, the eye had still not
lost its dominance.
For their
movement-studies artists called in the science of mechanics. But
they did little to advance it. Leonardo's work, being unpublished,
produced little effect. In spite of the classical texts of
Vitruvlus, Hero, and Ctesibius, established theory ended with
statics. In dynamics perpetual motion was still sought after, "
gravity " and " levity " still made things seek their "natural"
places, and the naive point of view held sway that force is needed
to keep up a uniform motion. It was otherwise with practice as
opposed to theory. Many early clock mechanisms are remarkably
well-balanced in their action, though without the pendulum their
accuracy could only be low. With the growth of trade, however,
punctuality began to be demanded in other matters than religion.
The Renaissance metal workers achieved a virtuoso's skill with
mechanical toys; and when jointed-metal work was going out for
armour, the great surgeon Ambroise Pare found a new niche for it in
the manufacture of artificial limbs (c. 1560). Thus craftsmanship
was ready to pick up applications of mechanical theory in the 15th
century.
In chemistry there
was not yet a body of exact ideas, but an alchemical literature and
an oral tradition of craft knowledge. There were balances and
weights of considerable accuracy. The chemical crafts already made
and used in some quantity the fundamental reagents, such as
sulphuric and nitric acids. Distillation had been, practised from
the 11th or 12th century. The distillation of spirits became a
considerable trade in the 16th century. The German mining and
metallurgy of the 16th century were already old. Italian glass
dated from at least the 12th century, and by the end of the 16th
had reached an artistic climax. Gunpowder was already an industry,
though gun barrels were still very crude. Drugs were a chief
article of long- distance trade, and were responsible for a great
diffusion of chemical technique. Toxicology, though little
understood, was much practised. Like the chemical weapons of
to-day, it contributed its quota to the tradition of chemical
skill. In all this, much future chemical knowledge was implicit,
but a major deficiency was the lack of clear conceptions of the
nature of gases and of experimental technique for handling them.
But this was itself only an aspect of a deeper deficiency of ideas:
the concept of the physical, of bodily materiality as we understand
it, was lacking. Ideas were still, for the speculative mind, more
real than material things. Science awaited th idea of a material
something existing independently of the observer and underlying,
essentially unchanged, the transformation and varieties of matter,
such as fusion, solution, chemical reaction. But in fact this idea
only began to grow definite in the 17th century. It did not
mature until the early 19th century. Without it, in
those early days, men were helpless: helpless in physiology;
helpless in physics. Without it, optics and astronomy all through
the 16th century were largely exercises in geometry. Heat was not a
branch of physics but a chemical element; while the alchemists made
what seem to us gross confusions of material substances and
abstractions or qualities such as colour. Thus, the ability to make
a substance look like gold seemed to them at least an approach to
actual transmutation. At the opposite extreme, they held that,
whatever the appearances, each firing or distillation refines away
more of a thing's external "dross" or "accidents" and brings us
nearer its quintessence or "soul," which is the elixir of life or
the philosopher's stone.
The Greeks, having
analysed the world into the fiery, the liquid, the earthy, and so
on, did not use these as mere convenient abstractions, but rather
treated individual substances as particular cases of these
underlying realities. The alchemists identified the realities with
particular material substances: sulphur, mercury, and salt
respectively. Nor was this mere verbiage. They gave such symbolic
correspondences practical effect. That between the planets and the
chemical elements constituted a connection of alchemy with
astrology. When one dealt with a metal, its planet had to be
in the proper position. The conjunction of fire and water among the
elements was correlated by Renaissance geologists with the fact
that volcanoes are always near the sea. The conjunction of fire and
sulphur was connected by Paracelsus with the preparation of the
very "fiery" substance, ether, with the aid of sulphuric acid. It
was long before men found anything better than such apparently not
unpromising starts ; and they only did so after decisive advances
had been made in physics.
The service of all
the centuries of alchemy was that of trying all the possible
permutations and combinations of all the substances known, mineral,
vegetable, "spiritual," "aerial", of clearing away those which did
not interact, and of slowly fixing attention on the less accidental
features of those which did. Three individuals of note soon
after 1500 were were trying to free chemistry from mysticism and to
bring it into touch with those craft-sources from which it was to
draw such wealth. Paracelsus (c. 1493-1541) was perhaps a typical
Renaissance braggart. It has still to be proved that he knew of
hydrogen as such; while it was another, Valerius Cordus (1515-44),
who gave the first non- mystical account of the sulphuric
preparation, of ether. But Paracelsus was also a lifelong voyager
in search of facts, with a hot tongue in his head for the
pomposities of contemporary scholarship and medicine. Agricola
(1490-1555) a metallurgist was a much quieter figure, a collector
of information and specimens, a genuine practising expert in his
subject, an exemplar of the scientific virtue of
sobriety.
Paracelsus, who was
more a doctor than a chemist, was one of the first to insist that
the body must be viewed as primarily chemical. He favoured mercury
and other mineral drugs at the expense of the vegetable decoctions
of the time. In fact, like Agricola, he was a keen mineralogist,
and had glimmerings of the ideas which later developed into
geology; such as that of the succession of the rocks. But a few
solitary voices were not enough. In the 16th century a new burst of
religious fanaticism flooded Western Europe. It was
after these men, that isolation swallowed up the science of
chemistry.
Nevertheless, from
the above account it is clear that the major procedures for
investigating the workings of nature had been defined as
‘observing’, ‘taking apart’,
‘transforming’, ‘reasoning with numbers’,
and theorising. With regard to theorising, science still needed
abstractions narrow enough to make predictions which are
disprovable, if false, by experiment.
