4. The picture and the thing

Explanations are analogies and metaphors, not the reality.

This is the fifth post in this series. If you haven’t read the Introduction titled The Myth of Scientific Uncertainty, and posts 1 and 2, you may want to do those first.

This picture by the surrealist Rene Magritte, is humorously but astutely titled, “This is not a pipe.” He is not gas-lighting; he’s saying that a picture of a pipe is not a pipe. For me, this beautifully illustrates a core characteristic of scientific explanations. They help us ‘picture’ or ‘imagine’ a phenomenon, but they are not the phenomenon.

For a scientific example, consider these representations of the molecule ethanol.

The first gives the chemical composition in terms of the number of atoms for each element. From this and tables of the characteristics of the elements we can calculate the molecular weight and the weights of all the isotopes. The structural diagram shows how the atoms and their bonds are arranged. From it, we can see the alkane and hydroxyl groups by which we can explain how ethanol is soluble in both water and hexane. And in the stick model, we can see the tetrahedral distribution of the carbon bonds and the 104.5º angle of the oxygen bond.

But none of these representations of ethanol reveal or explain all its characteristics, nor is it possible to do so in a single figure. There are the vibrational and rotational frequencies of the bonds and their strengths, liquid ethanol’s boiling and freezing temperatures, the optical absorptivities in the liquid and gaseous states, and so on and on. Each of these has its own set of laws and the explanations for them.

So, there are many representations of ethanol, and each is far from being complete. Further, the qualities of ethanol that are significant, and the ways they are meaningful, differ for the organic chemist, the spectroscopist, and the physiologist. Meanwhile, ethanol molecules, with all their known and yet-to-be-revealed qualities, just are what they are and do what they do.

Even though incomplete, only analogous in specific ways, and subject to revision, the many ways we ‘picture’ phenomena can be extremely helpful. As Erica Thompson says in her recent book^[1],

When you create a metaphor, or model or meme, you are reframing a situation … .so that we can see it from a new perspective, make unexpected links, and create stories and explanations that help us think collectively, as well as individually about the implications of the information we have.

Take the concept of the sun’s mass distorting the space around it as shown in this geometric diagram:

With this illustration, we can readily imagine circular orbits of the planets maintain their path along a circular line because of their momentum. We can even see how tilting that path would produce the more commonly found elliptical orbits. And thinking of a similar distortion around the mass of the earth we can imagine the paths of our satellites, real and artificial, and how an object separated from the earth and lacking a satellite’s orbital momentum will fall. Then, placing the space distortion diagrams for the earth and sun on the same plot, one can find the point where their attraction is equal, the ingenious location chosen for the remarkable James Webb Space Telescope.

Furthermore, analogies have often been central in the formation of scientific breakthroughs. Think of the Doppler effect, known to occur with sound, but imagined applying to light beams as well from which we deduce the red shift in light from distant galaxies.

Because the explanation of a phenomenon is not the phenomenon, but a model or analogy, there could be more than one credible and useful explanation. In fact, both Poincare^[2] and Einstein^[3] have said that there can be many reasonable explanations for a law or a set of observations. Our imagination may only present one or two, but we should not stop conceiving others as soon as we have one that makes sense. There may be others that do even better or are more useful in certain contexts.

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[1] Thompson, Erica, Escape from Model Land, Basic Books, New York, 2022, pp.31 and 45.

[2] Poincaré, Henri, Science and Hypothesis, First English translation, Walter Scott, London, 1905. My copy is the Dover edition, 1952. p. 167.

[3] Albert Einstein, Induction and Deduction in Physics, Berliner Tageblatt, 25 December 191.