This is the first in a series of posts by fellow physicist Marco Piani on the science in the television show The Big Bang Theory.
In Season 5 Episode 1, "The Skank Reflex Analysis", we see Sheldon face "certain death" during a paintball battle, standing defenseless and shouting out "Geology isn't a real science!", in this way triggering the angry reaction of the geology paintball team:
Why does Sheldon say that? We know that Sheldon has, let us say, a "mild" superiority complex when it comes to science. He is a theoretical physicist, and thinks that Physics is the discipline that deals with the fundamental laws of nature, hence the queen of sciences. All other scientific disciplines come second, and he goes as far as to consider engineers "umpa lumpas of science" in Season 1 Episode 12
But in the paintball scene Sheldon does not simply make fun of geology as a "lesser" science; he actually expresses his belief that geology is not a real science. His is a pretty harsh statement, and we understand why the geologists are so pissed off not to think twice before shooting Sheldon down!
While we do not endorse Sheldon's words, let us try to understand the possible reasons behind his verbal attack.
The question we should ask ourselves is: "what characterizes science?" It is actually a tough question, and there is an entire branch of philosophy that deals with it. It is clear that we will not even scratch the surface of the issue in this post. Nonetheless, we can at least say that one of the key concepts is that of "scientific method", that is, of how scientists proceed in establishing the body of knowledge called "scientific knowledge". What this method is or should be, and whether scientists actually adopt it in their normal practice are exactly the kind of questions addressed by philosophy of science. One widespread point of view (closely related to the ideas proposed by Sir Karl Raimund Popper (1902-1994)) is that science advances through the empirical falsification of hypotheses formulated to explain the results of observations. That is, hypotheses are made that in principle would allow to "compress" the information collected in numerous observations. For example, when we have a pen in our hand and we open the hand, the pen falls. The same happens with an apple, or a ping pong ball; thus, we may tentatively express our belief that "when we let go of any object, it always falls". Such a hypothesis can then be "tested", by letting a new object fall. If it does fall, our hypothesis—that all objects fall—is corroborated by observation, and we gain confidence in it; if it doesn't (e.g., if we let go of a string attached to a balloon full of helium, and it flies away), we have to go back to the drawing board to design a new theory that is compatible also with the new event we have experienced—the balloon and the string flying away. What is important is that we did test our hypothesis, verifying whether predictions made assuming the truth of our hypothesis actually happen. Even more importantly, we are ready to change our "theory" if its predictions turn out to be wrong. Of course, this is a simplification and an idealization of the scientific process, and real life research activity can be very different from this:
We are now in the position to better understand Sheldon's statement. For example, we can imagine that what Sheldon is pointing out is that geology does not allow for an easy implementation of the scientific method. One problem is that geology deals with processes—like the formation of mountains, or the drifting of continents—that take place in very long periods of time. So what a geologist can see is often only a snapshot of these processes (as if we could only see a picture of the object halfway between our hand and the ground, rather than the whole motion). On the other hand, a related problem is that geologists cannot set up controlled experiments that can be repeated to test their theories: we are given one Earth, and the geological processes that happen on its surface as well as in the underground are mostly out of our control. We are almost always limited just to witness them. Of course, what geologists actually do is much more than witness passively. As usual you can find more information on Wikipedia:
Actually, what might have triggered the criticism against geology of that snobby theoretical physicist of Sheldon, is the relevance of "applied geology" in the modern world, which goes from mining to environmental issues.
Even if, like Sheldon, I am a theoretical physicist, I am very happy to call geologists "fellow scientists". I must add that I am also a peaceful man, but I know that my inner geek will sooner or later induce me to take part in a paintball battle. Scientist or not scientist, surrender, or be stained!