Scientific Method Pt II: Another Application and Critical Comments

Today, before we turn to criticisms of the scientific method, we will first look at another application of Galileo's method.  Consider arguments about the daily, or diurnal, movement of the earth.  One might wonder why we feel no wind from the movement of the earth.  Or one might wonder why gravity pulls things straight down rather than at an angle.  Indeed, these considerations seem to show that the earth is stationary.  It does not seem as if the motion of the earth has an impact on the physical laws that govern the movement of things on this planet.

Galileo responds with an analogy.  Imagine standing high on the mast of a ship.  If you were to drop a stone, it would land directly below where you had dropped it--even though the ship is moving just as the earth is moving!  This analogy is not yet conclusive, however.  The scientific method requires that there be a causal explanation of the movement of objects.  One explanation for why we feel no wind from the movement of the earth is that the atmosphere of the earth rotates with the earth.  This is a causal explanation for why we feel no wind from the movement of the planet.  Also, consider the movement of a stone that is dropped.  At the time that the stone is dropped, it is already moving at the velocity of the earth.  As it falls to the ground, it maintains this motion, which is why it falls directly below where it is dropped.  Both the stone and the ground below it have the same motion, so it appears as if they stay in the same location in relation to one another.

Dr. Bencivenga notes that the scientific method does not prevent Galileo himself from making serious mistakes.  He notes two important mistakes in particular.  First, Galileo thinks that stars and planets move in perfectly circular motions.  A contemporary thinker, Thomas Kepler, was correct to theorize that the planets move in an elliptical shape.  Second, Galileo was very invested in his explanation of the tides.  He thought that because the earth moves on a rotation around its own axis as well as around the sun, this creates a very irregular motion that causes the waters of the oceans to slosh around.

Another criticism of the method is that it does not help us to make a choice between two opposing theories.  Both the view of Ptolemy and the view of Galileo are able to provide a causal account for the evidence.  Both can provide   Ultimately, Galileo claims that his view is better because it is more natural.  Specifically, he appeals to a notion of simplicity in justifying the truth of his own view.  He thinks that it is simpler to explain the apparent motion of the heavens if me hypothesize that the earth rotates around the sun rather than other planets rotating around the earth.  He also thinks that his explanations are more elegant.  Another notion that he appeals to is a notion of proportionality between causes and effects.  In short, little things have little causes and big things have big causes.  According to this principle, it seems silly to think that the earth (which is relatively small in the cosmos) could cause the heavens (relatively large compared to the earth) to move.  Proportionality, elegance and simplicity are three intuitive principles that Galileo appeals to.  None of the three are themselves justified by the scientific method.

In short, Galileo thinks that the Copernican system is more credible and reasonable.  Dr. Bencivenga questions why we should think that the universe is organized according to credible and reasonable principles?  Indeed, Galileo himself at certain points notes that we should not think that the universe operates only in ways that we are able to understand clearly.  The actual events that happen in the universe are not limited simply by what we find to be reasonable and credible.

The upshot of all of this is that there is no single method that can be used infallibly to find the truth.  Mistakes will be made when searching for the truth.  Trial and error are both important in the quest for knowledge.  Galileo thinks that we must accept that our searches for knowledge may not always yield knowledge.  We must have intellectual courage in the face of this daunting fact.  Not only do we need courage but also freedom in order to perform science.  Freedom is necessary in order to pursue alternative explanations and to try to explain things in new ways.