Galileo (1564-1642)

Italian astronomer and natural philosopher. Galileo finally manages to destroy the Aristotelian theories of motion, but perhaps more importantly for what is to come in the scientific revolution he instigates the idea that mathematics can apply precisely to the world around us and that we can produce mathematically framed laws that relate to this world.

In relation to the reverence granted to Aristotle at this time, Galileo’s break with tradition and insistence that we test matters for ourselves is also significant, as is the support some of his work lends to the Copernican theory. Taken as a whole his views on motion are certainly not the last word, but they lay the basis for the more sophisticated treatments to come, especially in the areas of inertia and frames of reference. Although on the whole Galileo’s views are new and radical, he does hold onto the old notion that the proper motion of planets is circular, and non-inertial, that is they require no force to keep them in motion; in fact the orbits are ellipses, and both circular and elliptical orbits need forces.

Galileo also is famous for incurring the wrath of the Catholic Church and the inquisition. Galileo is at first careful about his pro-Copernican views. Johannes Kepler urges Galileo to step forward and be counted; Galileo replies that if more men thought like Kepler he would. With the telescopic discoveries of 1610, Galileo believes he now has proof of the Copernican theory. Clerical reaction to Galileo is by no means uniformly unfavourable; Cardinal Baronius famously comments: “The Bible teaches the way to go to heaven, but not the way the heavens go”. However in 1616 Galileo is ordered by the church not to hold or defend Copernicanism. The new Pope Cardinal Barberini (Urban VIII) discusses these matters with Galileo, and allows him to publish if he reaches no firm conclusion, the Pope’s position being that God can make it seem to men that heliocentrism is correct if he so chooses, but the bible says that geocentrism is correct. When Galileo does publish, this position is put into the mouth of the most foolish character in his book, and the Pope is persuaded that this is a personal insult. Galileo is tried, and admits his guilt; it is a later fabrication that he tapped the ground and said “and yet it moves” as he got up after apologising. The sentence of house arrest was less harsh than it might have been.

Related Topics:

	Physics
	History
	The Relation of Science & Religion

Contributed by: Richard P Whaite