4.5 The Message from the Plane

We began this chapter with a number of questions. One of them has not yet been explicitly answered: what is an experiment? Galileo saw an experiment as a question put before Nature. The secret of a great experiment lies more in how well that question is put than in the measurement technology used. For instance, an accurate timekeeper would add very little value to Aristotle's experiments with free fall in water because he posed the question in a way that muddled the problem. Precision can make it easier to interpret the results of an experiment that is well conceived, but if we want Nature to answer our questions a keen eye and a bit of imagination are more valuable assets than a precise instrument.

It would be preposterous to judge the scientific quality of an experiment by the sophistication of the measuring instrument used. In that case, weighing your fruit on the electronic scales at the supermarket would be far more valuable than many groundbreaking experiments in the history of science. The theoretical knowledge embodied in such scales is, after all, considerable. Since scientists seek to understand the world it is important for them to recognize trends and regularities. Scientific progress does not mainly lie in the acquisition of accurate numbers; it lies in the identification of the patterns behind the numbers. Galileo's experiment is important because it shows how a simple setup can unveil a distinct pattern in Nature.

Koyré seems to have been more interested in his own agenda than in this aspect of the experiment. In his mind, he had reduced the purpose of the experiment to the measurement of a constant, but Galileo was doing something more complex and interesting than that. He was trying to find out how acceleration occurs. We should not confuse experiments with measurements. Measurements are just structured ways to acquire data and they are made all across society, from research laboratories to the fruit market. Measurements are not a unique characteristic of the experimental method, because passive observers also measure things. What makes experimenters unique is that they interact with what they measure. They create specific conditions to answer specific questions.

Settle showed that there is more to a good experimenter than the ability to implement theoretical knowledge in a laboratory setup. The will and ability to handle the “nuts and bolts” of the setup is often crucial for success. Theoretical considerations do not necessarily dictate which approach to a problem is most suitable; practical considerations are equally important. An experiment is not theory incarnate.

Drake showed us that it is very likely that Galileo used the inclined plane to make a genuine experiment, rather than just a demonstration. He also showed that there is much more to science than precision in measurement and calculation. A successful experimenter needs the ability both to ask meaningful questions and to find useful means to answer them. Though precise measurements and calculations are significant features of any exact science, a creative mind is equally important. Experimenters are like artists – they must work with mind, hand and eye, and find a harmony between them.

It must be said that experimentation is a creative activity. The inclined plane was not a given. Galileo had to find a way of exploring his problem that made the investigation possible, and he created the plane to this end. The French author Émile Zola said that art is a corner of creation seen through a temperament. Likewise, science can be said to be a corner of reality seen through an intellect. The difference is that science must stand up to scrutiny. Where art is a subjective reflection, science must give an objective account of reality. But that is true of the theories that are the end result of scientific enquiry. The path to them is often hilly and covered with brushwood; clearing a way through the thicket may require considerable creativity.

Experimenters do not settle with collecting numbers. They create unique conditions to explore the world around them. At the end of the day, experimenters see the world more through an artist's eye than through the eye of an accountant.