Thine Own Self: Scientific Knowledge and Scientific Method

"Thine Own Self" (TNG) is a very interesting episode (as regards Data—the B-plot about Troi is less satisfactory). Data loses his memory while on a mission to a planet where he is supposed to be recovering radioactive debris, and wanders into a village carrying it. The village is roughly Early Modern, early scientific revolution, and is basically friendly. [1] A notable character is Talur, the local doctor and teacher, who is something of a scientist.[2] When the radioactive metal (some of which has been made into ornaments) causes illness, Data tries to discover the cause, and she assists.

The writers seem to have thought of Data as having a "more scientific" approach, and indeed I have seen commentary describing Talur's ideas as "superstitious". Those comments illustrate a lack of knowledge of the history of science, of course. But in fact, the division is different. Data has far more scientific knowledge that Talur, and seems to be progressively regaining memory of it (his amnesia is essentially about his own identity). Data presumably uses his knowledge of scientific method to discover his cure. But we don't see that, and in their previous interactions we see Talur attempting scientific method while Data follows "authority".

In a notable scene, Talur teaches children that all substance is composed of the four elements rock, sky, fire, and water[3] She explains how they can all be found in, for example, wood, illustrating that burning it releases fire. Data however objects that "I believe you are reasoning by analogy, classifying objects and phenomena according to superficial observation rather than empirical evidence. Wood, for example, does not contain fire simply because it is combustible.... Wood, like any complex organic form, is composed of thousands of different chemical compounds, none of which is fire."

This is, however, not very sound.[4] Talur is giving the phlogiston theory of fire, which was held in modern western science until the late eighteenth century.[5] The idea is that combustible materials contain some substance (given the name 'phlogiston") which was released as fire. Oxidation (rust) was a slow form of the same thing. The phlogiston in the air was absorbed by plants. This was a coherent and elegant theory that explained the data. However, like many theories, it was eventually superseded. It ran into problems because it was found that materials could get heavier after burning. This could be explained by phlogiston being lighter than air[6] but since the weight gain was then found even in vacuum, phlogiston would have to have negative mass. When it was found that oxygen was always present in combustion, the theory was replaced by the idea that fire was caused by something combining with the wood. On the original data, that's a rather odd idea.[7]

Data, however, knows that fire is not an element, and that wood contains thousands of substances. But that's knowledge that he happens to have. He isn't giving a valid scientific reason against Talur's theory. If I time-travelled back to the seventeenth century and met Sir Isaac Newton, I would know that his theories are not quite right, because I have learnt about Einstein, but that doesn't mean I would be a better scientist than him, or indeed that I am any sort of scientist at all. Nor is it surprising that Talur rejects Data's statement about thousands of chemicals in wood. Data complains because she told him about there being wild animals in the mountains, on the basis that she hadn't seen one, but he expects her to accept his rather less plausible and completely unsupported assertion about thousands of chemicals?

Even in devising his cure, Data uses a whole lot of information that he just knows, about "interstitial transparency and membrane integrity" for example. In fact, Data is using his memory as Authority.

The concept of "Authority" doesn't mean "power" here—it means accepting some belief or theory because you got it from an "authoritative" source. In ordinary life much of our knowledge is of this sort. However, a key feature of the scientific revolution was the demand that things had to be shown—you couldn't include "Aristotle says" in your data. The Royal Society's motto is "Nullus in verba", meaning "Don't accept anyone's word", or more formally "Nothing on authority".

Data and Talur actually seem to work together quite well. Their discussion of common factors in causality shows Talur is clear on the concept. Confronted with Data's highly unfamiliar research, involving things like invisible particles, she is naturally hesitant but follows his ideas, while telling him she will have to review his data later.

To return to a more minor example mentioned earlier: Data challenges her assertions about monsters in the mountains—has anyone seen one. Not that she know of. So do they exist? We the viewers are inclined to say probably not, or any rate that the evidence is lacking. But at their level of society, there are a lot of far-off things you only know of by unattributed report. Although she should be more careful, "There are dangerous wild animals in uninhabited areas" is not really that remarkable an idea.

I said earlier that the villagers are basically friendly. It's true that some hotheads eventually attack and "kill" Data because they think he is causing the illness. But this is a response to what they not unnaturally perceived as a real threat—Data himself had noted that his presence coincided with the sickness—and they had not initially shown him any hostility for being different. Afterwards, they apparently realize that his cure (which he poured into the well) has saved them, and put up a nice metal marker at his grave.