I want to tackle a rather difficult subject today, one having to do with how science operates. I need to say from the beginning that I really like science; it’s one of the best, if not the best way to reason. This is not a critique or an indictment.
Having said that, science does possess a few limitations or, more precisely focuses that have an effect on the knowledge it produces. Scientists reading this – please read closely before forming an opinion.
What is science? To my mind, science comes about as a process of learning about the world. In philosophical lingo, science is an epistemology, a way of knowing. Specifically, it is a way of knowing about the physical world. From the early 20th century on, scientists have considered anything that does not have an observable physical (or energetic) aspect to be strictly off the table. No spirits, no minds, no agents, no God. Psychology, anthropology, cognitive science, and economics and a few other fields have tried looking at minds and agents recently, but generally in the context of what’s observable about them. Strictly speaking, those fields look at observable behaviors and expressed preferences. Purists might claim that these fields aren’t really sciences and I would take issue with that, but let us deal for the moment with the natural sciences of physics, chemistry, biology, geology, and astronomy, just to avoid trouble. The natural sciences study the physical world and only allow for physical (and energetic) explanations.
The real question – the deep and hard question – we like to ask deals with what makes scientific explanations scientific? The subject matter, certainly. I would say that scientists observe methodological naturalism (or more properly methodological physicalism); we only talk about physical things. Doesn’t mean the other things don’t exist; it just means we can’t talk about them scientifically in a meaningful way.
So far, so good. Science has a limited subject matter. Still, all physical explanations are not scientific explanations. I might say God shaped human out of the clay or that angels push the planets in their orbits. Neither one would qualify as a “scientific explanation” so we have to ask, what differentiates scientific explanations from other explanations of physical objects and events.
When I ask my scientist friends about the goal of science, they often tell me that science is about finding knowledge, a real understanding of the world. Alas, we don’t have an external way to verify our knowledge, so we have to judge it somehow. We have to ask how we justify our claims of knowledge? I go into this in depth in my post of 14 June 2011. Now I want to propose an answer. I think scientific justification always have to do with power. I’ve looked for a better word, but I can’t find one, though practicability comes close. Let me explain.
I like power because of a simple physics equation that seems useful:
power = work / time
Scientists, to my mind, have two major criteria for choosing explanations. Does it work? And, is it elegant? Work can be measured using a few simple questions:
1) How much data does it cover? The more instances, the more observations it covers, the better. Ideal scientific explanations cover all observations ever made on the subject and admit of no contradiction. No one has ever observed anything that does not fit with the theory. Good scientific explanations cover the vast majority of the data, with a few small unexplained phenomena. These stray data points, often called “outliers” can be attributed to experimental error. Explanations that cover more data or a greater proportion of the data are better.
2) Does the explanation allow me to make predictions? We’re constantly making new observations. I want to know whether my explanation will tell me in advance what I am about to observe. Good explanations allow us to anticipate nature. The more consistently accurate the predictions, the better the explanation.
3) Does the explanation allow me to manipulate my environment? Engineers are most interested in predictions of this type. When I do A, B will happen. Ideal scientific explanations always tell us what our actions will do in the world. When I let go of the pen, it will fall toward the ground. Good explanations tell us what will happen almost every time or perhaps give us a probability for different outcomes. Taking the medicine reduces my chances of a heart attack by 50%. Better explanations give me more control.
Scientists and philosophers of science point out – rightly – that this doesn’t sum up scientists preferences. Scientists prefer simplicity, elegance, even beauty in their explanations. How does that fit in? I think that has to do with the time element. Better explanations take less time to understand and apply.
4) Can the explanation be expressed concisely? Can you write it down in a simple equation or a short sentence in a way that unambiguously allows the reader to do the work? Shorter is better. Thus, an equation like E = mc^2
warrants praise as one of the best scientific explanations ever. Not only does it apply to all known matter and energy (1), allow us to predict the energy output of stars (2), and know just how much uranium to us for the size explosion we want (3), it does so using only 5 characters (4). (Bonus: 3 characters are constant!)
A scientific explanation maximizes the ratio of work over time. Thus a not quite accurate physics of dynamics (how moving things interact) called Newtonian Physics wins out over an almost completely accurate physics of dynamics (Quantum Mechanics plus General Relativity) because the equations are considerably simpler. We keep both systems around because we recognize the importance of the ratio. 77/3 > 99/15. So the efforts to keep the numerator (top, work) high and don’t always line up with efforts to keep the denominator (bottom, time) low.
I suspect, at the end of the day, scientists will keep any explanation that yields more work, but won’t eliminate competing explanations until the work to work to time ratio can be bettered.
So, science is highly pragmatic. It means getting the most out of your explanations that you can.