Ethical Theory Spring 2022

Moral and Scientific Observations


Gilbert Harman tries to show that ethics are subjective by contrasting ethical thought with the sciences. He maintains that the observations that we make when examining the natural world are best explained as encounters with objective reality. By contrast, he believes, moral observations are best explained as the products of our upbringing and psychology. Our moral thoughts would be the same even if there were no moral facts to observe but the same is not true of observations in the sciences.

What is an observation?

An observation is something you experience. Harman contrasts two different observations:

  1. Your observation that it is wrong for the hoodlums to burn the cat (Harman 1977, 4).

  2. A physicist’s observation of a vapor trail in a cloud chamber (Harman 1977, 6).

Harman thinks that all observations require what he calls theories. Your mind needs to interpret the colored splotches that appear on the back of your eyeballs.

In the first case, you have theories about animals, pain, and morality that come into play when you observe that burning the cat is wrong.

In the second case, the physicist has theories about how the cloud chamber works and what atoms are like that come into play when he observes a proton making the vapor trail.

Without these theories, neither observer would make the observations that they did.

What is the difference?

Here is Harman’s chief claim.

observation plays a role in science that it does not seem to play in ethics. The difference is that you need to make assumptions about certain physical facts to explain the occurence of the observations that support a scientific theory, but you do not seem to need to make assumptions about any moral facts to explain the occurence of the so-called moral observations I have been talking about. In the moral case, it would seem that you need only make assumptions about they psychology or moral sensibility of the person making the moral observation. In the scientific case, theory is tested against the world. (Harman 1977, 6)

That is, you need to assume that there really is a proton that causes the physicist to observe the vapor trail in the cloud chamber.

By contrast, you do not need to assume that cat burning is really wrong to explain the observation that what the hoodlums did to the cat was wrong. Harman thinks that the beliefs of the observer alone can explain that observation.

Questions for discussion

You can challenge Harman’s argument from either direction.

  1. You can say that the physicist’s psychology alone can explain the physicist’s observations. Look at all the false physical theories that have been “confirmed” by experiments over the years, for instance. You do not need to assume that there were facts causing the observations in those cases because the observations were wrong.

  2. You can say that you do need to assume that causing pointless suffering really is wrong in order to explain the observation that what the hoodlums did was wrong.

In our discussion, I want to talk through how these objections would go. That is, I want to talk about how could we fill them out, how Harman would reply, and what we ourselves think.

Cat burning

Harman doesn’t go into much detail about why moral observations are fully explained by the upbringing and psychologies of the people who make them. One thing he could do to help make his case is to note that attitudes about cruelty to animals vary across cultures. That suggests that the best explanation of the observation “that’s wrong” really is cultural, namely, people from a different culture would think “that’s funny” when they see something similar.

Here’s an example of how officers in the English Civil War “diverted and cheered their men with military tricks and jokes” (Donagan 2008, 280).

I should acquaint your honour, what frequent alarums we gave them [the Parliamentary army besieging the town -mjg] by fire-balls, lights upon our steeple, by dogs, cats, and outworne horses, having light matches tyed about them and turned out upon their workes; whereby we put the enemy in such distraction, that sometimes they charged one another: this recreation we had in the middest of our besieging (Letter from Bar. Scudamore to Lord Digby circa 1645, reprinted in Duncumb 1804–1882, 1:279)

In other words, one way they kept their spirits up during the siege was by setting animals on fire and sending them towards the other army. The author of the letter calls that recreation.

I suppose you could read this as saying that they were entertained by the confusion this caused in the besieging army. That is, it was not the flaming cats and horses that they found entertaining, but rather the panic in the other army. Still, it does suggest a very different attitude towards animal cruelty than we have.

Rutherford’s Incredible Event

I mentioned this example as evidence that the experimental method has a way of breaking through the “theory-ladeness” of observations. Here, Ernest Rutherford had a theory of the atom that he expected an experiment to confirm. When the experiment surprised him, he revised his theory.

… I would like to use this example to show how you often stumble upon facts by accident. In the early days I had observed the scattering of α-particles, and Dr Geiger in my laboratory had examined it in detail. He found, in thin pieces of heavy metal, that the scattering was usually small, of the order of one degree. One day Geiger came to me and said, “Don’t you think that young Marsden, whom I am training in radioactive methods, ought to begin a small research?” Now I had thought that too, so I said, “Why not let him see if any α-particles can be scattered through a large angle?” I may tell you in confidence that I did not believe that they would be, since we knew that the α-particle was a very fast massive particle, with a great deal of energy, and you could show that if the scattering was due to the accumulated effect of a number of small scatterings the chance of an α-particle’s being scattered backwards was very small. Then I remember two or three days later Geiger coming to me in great excitement and saying, “We have been able to get some of the α-particles coming backwards…”. It was quite the most incredible event that has ever happened to me in my life. It was almost as incredible as if you fired a 15-inch shell at a piece of tissue paper and it came back and hit you. On consideration I realized that this scattering backwards must be the result of a single collision, and when I made calculations I saw that it was impossible to get anything of that order of magnitude unless you took a system in which the greater part of the mass of the atom was concentrated in a minute nucleus. It was then that I had the idea of an atom with a minute massive centre carrying a charge. (Rutherford 1938, 68–69)

Here is an explanation of this experiment from a source that has sadly disappeared from the internet.1

At the turn of the century, there was little known about atoms except that they contained electrons. J. J. Thompson discovered the electron in 1897, and there was considerable speculation about where these negatively charged particles existed in nature. Matter is electrically neutral; some positive charge must balance the charge of the electron. One popular theory of the time was called the ‘plum pudding model’. This model, invented by Thompson, envisioned matter made of atoms that were spheres of positive charge spiked with electrons throughout. Electrons were chunks of plum distributed through a positively charged sphere of pudding.

In 1911, Ernest Rutherford performed an experiment to test the plum pudding model. He fired energetic α [He2+] particles at a foil, and measured the deflection of the particles as they came out the other side. From this he could deduce information about the structure of the foil. To understand how this works, imagine shooting a rifle at a mound of loose snow: one expects some bullets to emerge from the opposite side with a slight deflection and a bit of energy loss depending on how regularly the pile is packed. One can deduce something about the internal structure of the mound if we know the difference between the initial (before it hits the pile) and final (after it emerges from the pile) trajectories of the bullet. If the mound were made of loose, powdery snow, the bullets would be deflected very little; if the bullets were deflected wildly, we might guess that there was a brick of hard material inside.

Rutherford expected all of the particles to be deflected just a bit as they passed through the plum pudding. He found that most of the α’s he shot at the foil were not deflected at all. They passed through the foil and emerged undisturbed. Occasionally, however, particles were scattered at huge angles. While most of the α’s were undisturbed, a few of them bounced back directly. Imagine if something like this happened at our mound of snow. We shoot bullets at the pile for days, and every round passes straight through, unperturbed – then a bullet hits the snow, reflects back, and splinters the gun’s stock! Rutherford’s result lead him to believe that most of the foil was made of empty space, but had extremely small, dense lumps of matter inside. No other model accounted for the occasional wide angle scattering of the α. With this experiment, Rutherford discovered the nucleus.

Key Points

  1. The relationship between theories and observations.

  2. The difference between moral and scientific observations, according to Harman.


Donagan, Barbara. 2008. War in England 1642-1649. Oxford: Oxford University Press. doi:10.1093/acprof:oso/9780199285181.001.0001.
Duncumb, John. 1804–1882. Collections Towards the History and Antiquities of the County of Hereford. Vol. 1. Hereford.
Harman, Gilbert. 1977. The Nature of Morality. New York: Oxford University Press.
Rutherford, Ernest. 1938. “The Development of the Theory of Atomic Structure.” In Background to Modern Science: Ten Lectures at Cambridge Arranged by the History of Science Committee, 1936, edited by Joseph Needham and Walter Pagel. Macmillan.

  1. This is where I found it, for what it is worth:↩︎