The historiographic implications of the Galileo Affair
The apologetic reading insists on the fact that rationality was on the side of the Catholic Church and that Galileo was not putting forward the theory most acceptable to reason in his day. But contrary to what this reading suggests, this want of rationality, cannot serve as an excuse for the power games at work, for the use of moral pressure or for the condemnation proper. Whilst admitting some relativity in the regimes of rationality, it is not possible (short of making a category error) unreservedly to absolve the line of action taken by the church. At the same time the heroic reading that turns Galileo into the ill-used rationalist forerunner of modern science is itself under scrutiny. Going by the standards of the aforesaid modern science, it is hard to call what Galileo produced in defence the Copernician system “scientific”.
However, from an epistemological point of view, the circularity in Galileo's argumentation and even in his observations aimed at validating the Copernician theory brings out something more significant. The way he argued is an exemplary illustration of a broad feature in any theoretical reasoning, a feature the philosophy of science has observed and reiterated later with Thomas Kuhn's[1] The Structure of Scientific Revolutions (1962): a theory, its proofs, its methodology, the value of the instruments used and the observations that underpin it are interdependent, for no sooner does one back the Copernician theory than the observations made by Galileo become correct confirmations of that theory. Theories and observations form a whole obeying a specific rationality, a rationality all too often incompatible with the rationalities of other theories or systems of thought.
This notion of circularity is crucial: granted that the earth is not the centre of the universe, there can be no more cause to distinguish between the sublunar and the supralunar, and therefore no cause not to trust such an instrument as the spyglass. Yet it is precisely the spyglass that would help dislodge the earth from the centre of the universe. So, at the beginning of such a paradigmatic change, there is an act of trust, some say an act of faith. And at one fell swoop the boundaries between scientific theories and other systems of thought fade away. If every theory is founded in a circular argumentation between the theory to be proven and the evidence towards it, it becomes impossible to make absolute claims in defence of any theory whatsoever. In the patterns of engagement between contradictory proposals arising from two different theories, a fourth possibility exists:
4: in S rationality, O is S and in R rationality, O is R wherein S has nothing to say on R rationality or the reverse.
Thus, some specialists of the history of science show how a true coexistence of different systems of thought is possible without making it necessary for one to bow out to the other. With this in mind the Galileo affair is a warning against the totalitarianism of thought systems, be they religious or scientific; and Galileo who, a patent lack of rationality not withstanding, defended a system which today seems more rational from a scientific standpoint then assumes a new significance: he emerges as the anti-hero of anti-totalitarian systems of thought.
