Free A Brief Guide to the Great Equations by Robert Crease Page B

the image would prove explosive. Galileo had insisted that the book of nature was not written in ordinary words; its characters were fundamentally different from the words of the scriptures, of Aristotle, and of any textual author. ‘It is necessary for the Bible’, Galileo said, though he might as well have said it of the books of Aristotle, of the Church Fathers, or of any author, ‘in order to be accommodated to the understanding of every man, to speak many things which appear to differ from the absolute truth so far as the bare meaning of the words is concerned. But Nature, on the other hand, is inexorable and immutable; she never transgresses the laws imposed upon her, or cares a whit whether her abstruse reasons and methods of operation are understandable to men.’ 1
    Galileo’s arguments seem to have convinced Christina, but not the authorities. In 1616,
De Revolutionibus
was put on the Index, followed by Kepler’s textbook on Copernican astronomy,
Epitome
, in 1619, and Galileo himself came under attack. Partly in response he wrote
The Assayer
, containing the famous passage that ‘the grand book of the universe...cannot be understood unless one first learns to comprehend the language and to read the alphabet in which it is composed...the language of mathematics.’ Those versed in mathematics and physics, in other words, can know aspects of God’s handiwork that others cannot.
    Galileo chose his image carefully, and its roots were deep in Western metaphysics and theology. First, it used the traditional idea that God revealed his power, glory, and truth in the world. Second, it relied on the equally traditional notion that the Bible cannot go against clear demonstrations of logic or the senses. Finally, it appealed to the time-honored metaphor of nature as a book. Galileo was on solid theological ground.
    In fact, however, Galileo – perhaps without his being fully aware of it – had stood the old image on its head. The image of the book of nature now implied something almost opposite what it had before – that the signs of nature had their own self-contained meaning. To understand nature one did not need to rely on the Bible as an allegorical aid; studying nature was an independent activity best carried out by a separate, professional class of scholars. If anything, the book of nature now became the primary text – the blueprint written in technical language – and scripture the user’s manual, written in popular language.
    Galileo thereby used the image to defend not only himself but also all scientists, suggesting that they were as authoritative as the clergy. ‘The book of nature and those natural philosophers who interpreted it...assumed part of the role previously played by the sacraments and the ordained priesthood’, writes Harrison.
    But the image of the book of nature can haunt us today. One reason is that it implies the existence of an ultimate coherent truth – a complete text or ‘final theory.’ While many scientists may believe this, it is ultimately only a belief, and it is far likelier that we will endlessly find more in nature as our concepts and technology continue to evolve. Furthermore, the image suggests that the ‘text’ of the book of nature has a divine origin. The idea that the world was the oeuvre of a superhuman author was the precursor of the idea that it was the engineering project of an intelligent designer. This implication has led some contemporary sociologists of science to succumb to the temptation of characterizing scientists as behaving, and seeking to behave, in a priestlike manner.
    The most important lesson to be found in Galileo’s image is the need to keep developing and revising the metaphors with which we speak about science.

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‘The High Point of the Scientific Revolution’:
NEWTON’S LAW OF UNIVERSAL GRAVITATION

    DESCRIPTION : Gravity exists in all bodies universally, and its strength between two bodies depends on their masses and inversely as the