Overview

Ars sine scientia nihil est. It is clear that the word scientia, recorded in the minutes of the expertise held at Milan in 1400, does not carry the full modern meaning of a system of thought related to the physical universe. The word science today carries the implication of a more or less standard sequence observations have been made, a hypothesis constructed, experiments designed to prove or disprove the hypothesis, some mathematical analysis undertaken, and finally a theory established which can be used to explain past observations and predict new results. Newton's gravitational theory is of this kind. Observed planetary orbits could be explained by the assumption of the universal inverse-square law, and future motion could then be predicted exactly (or almost exactly the explanation for tiny departures from Newtonian cosmology had to wait for Einstein).

Babylonian astronomy was certainly a science. It was developed between 1000 and 500 BC, and based on accurate observations of the day-by-day positions of the sun and moon (and of the planets); numerical difference tables were then constructed from which future positions of the heavenly bodies could be predicted. Further, once the motions of the moon and sun had been determined, it was not difficult to predict when the moon would be close to the ecliptic at opposition or conjunction and hence tables of lunar and solar eclipses could be established.

The medieval scientia of building was of this sort. The word implied scholarship and learning knowledge acquired by the practice and study of...