What is Science?
What is science?
Before we address this, good to note what it isn't, because popular culture tends to confuse the issue significantly.
- Science isn't the same as technology.
In the modern era, when we think of technologies, we are usually thinking of applications of scientific discoveries, even of discoveries that seem, by themselves, rather academic. E.G. tunnel capacitors, electronic components based on the application of the principles of quantum mechanics. Nevertheless, many complex technologies have been around much longer than the practice of science and were developed by simple trial and error.
- Science isn't a body of knowledge.
This message often gets garbled in public education, where "learning science" typically means "learning about the information that the practice of science has yielded" rather than about the practice itself. Contrary to what "creation scientists" would have you think, you aren't doing science simply by referring to the scientific body of information or wearing a lab coat. You actually need to be using a very specific method.
- Science isn't purely descriptive.
There are many ways to describe nature. Whether the descriptions are "scientific" or not depends on whether they contain repeatable observations that can be used by the scientific method or not.
Fundamentally, science is methodological.
Why do we need a Scientific Method?
Because the human mind doesn't automatically process information in a way that's conducive to scientific thinking.
Consider Thomas Kida's Six-Pack of Problems.
- We prefer stories to statistics. No surprise. The human mind, as we know it today, seems to have arisen around 30,000 to 40,000 years ago, but we have had access to the kind of compiled information that forms the basis of statistics for only the last 5,000 years.
- We seek to confirm, not to question, our ideas. No surprise. All humans are, to some degree, egotists. Many of us are pathologically incapable of admitting a mistake. Training ourselves constantly to question our own ideas, especially the ones we really want to believe, requires genuine discipline.
- We rarely appreciate the role of chance and coincidence in shaping events. The idea that "shit happens" is a surprisingly modern one. We cling desperately to the notion that if we do the right things we will be OK and abhor the idea that random events (the drunk running into our car, the lightning bolt, etc.) can effect us. History, literature, and folklore are full of examples of human attempts to find order in chaos. Consider:
All of this reflects something fundamental about the human mind. We are pattern matching organisms, programmed to perceive patterns where ever possible. (The basic principle of Rorschach tests.) In our "wild" state, this ability was generally an asset, even if we were often mistaken.
- We sometimes misperceive the world around us. No surprise. We don't uniformly pay attention to everything in our environment. We focus on certain things and ignore others. In some cases, we actually hallucinate.
- We tend to oversimplify our thinking. No surprise. Life doesn't often give us time to perform thorough analyses of all options. Our ability intuitively to pick out a manageable number of good choices is usually a survival skill. When a leopard is bearing down on you, you don't have time to evaluate every possible escape route.
- We have faulty memories. We are suggestionable. Our memories can easily be influenced by our desires and expectations.
To protect us from these natural tendencies, we have developed a range of critical thinking skills. Think of them as the mental equivalent to martial arts skills. They don't come naturally but are very powerful, and have to be learned. They include:
The hypothetico-deductive method of science
The Scientific Method
The guiding principle of scientific inquiry was perhaps best summed up by a non-scientist, the novelist Arthur Conan Doyle, who placed into the mouth of his character Mycroft Holmes these words:
"First we eliminate the impossible options. What is left, however improbable, is the truth."
The modern practice of science is based on a method that employs that principle, with a little twist.
Key components of the scientific method:
- Observations: Any impression of the physical universe that comes to us directly through our senses or our indirectly through instruments. E.g. "I looked out my east window this morning and saw the Sun rise."
- Repeatability: The ability of two different individuals operating under the same circumstances independently to make the same observation. E.g. "My neighbor down the block also saw the Sun rise in the east."
Some types of observations are inherently non-repeatable. E.g. "My wife is the most beautiful woman in the world." Sweet, but unlikely that all observers would have the same impression.
- Patterns: Tend to become apparant when we make and compare many observations. E.g. "The Sun appears to rise in the East every morning." Humans are compulsive pattern recognizers, both seeing real ones and confabulating ones that aren't really there. The scientist's task is to distinguish the two.
- Hypothesis: A formal statement about a pattern of observations whose truth or falsehood is initially unknown. E.g. "The Sun always rises in the East." Remember, a hypothesis is a statement about a pattern of events, not a single observation.
- Hypothesis falsification: the scientific method does not absolutely prove anything. It can, however, disprove things. We do this by looking for observations that are inconsistent with our hypothesis. When a such an observation is made and verified, we consider the hypothesis to be disproven or "falsified." E.g. If the Sun were to rise in the North one day, the example hypothesis given above would be falsified. Obviously, being falsifiable is different from being false.
- Falsification is definite - "proof" is unattainable: When an inconsistent observation is made, the hypothesis is definitely falsified - i.e. it's dead dead dead. No amount of consistent observations will bring it back to life. But even if we see ten, a hundred, or a gajillion observations that are consistent with our hypothesis, we can never be completely sure that the next observation won't falsify it. Thus, one never definitively "proves" a scientific hypothesis.
- Statistical qualification: You may consider the foregoing to be an oversimplification. Well, OK. In our imperfect world of uncertainty - about the accuracy of observations and the identity of specimens - we usually resort to statistical tests of hypotheses. E.G.: we may say that there is a 95% probability of a hypothesis being falsified. Even in such cases, we frame our statements conceptually in terms of the falsification of a hypothesis.
- Non-falsifiable hypotheses: Hypotheses that are inherently impossible to falsify, either because of technical limitations or because of subjectivity. E.g.:
Another term for non-falsifiable hyoptheses is "speculation." I'm not saying that non-falsifiable hypotheses are bad or not worth pursuing. Lots of great art, literature, philosophy, and religious thought is deeply (and rightly) concerned with them. They just aren't a basis for scientific inquirey. They are beyond the grasp of science.
- "Chocolate is always better than vanilla." [subjective].
- "There are living beings in the Andromeda galaxy." [beyond technical grasp]
- A problem: Suppose you have a falsifiable hypothesis that consistently resists all attempts at falsification. At a certain point, it becomes sort of perverse to not provisionally accept it as "truth." Often, we see groups of such hypotheses dealing with the same general issue.
For example, humans have been watching the sun rise for over 100,000 years, and is always rises in the East. Not only that, the moon, stars, and planets also rise in the East! Such an amazing congruence of provisional "truths" about celestial bodies gets us thinking about the underlying mechanisms governing them. From this kind of situation we get theory.
- Theory: Set of universal rules that explain wide ranges of falsification-resistant hypotheses in terms of underlying processes. E.g. We now have theory that explains our earlier hypothesis about the Sun rising in the east: "Inertia causes the Earth rotate in the same direction on its axis once every day, causing observers on its surface to observe celestial bodies appear to rise in the East every day." These rules allow us to understand not only the sunrises we witness directly, but the rising of all celestial bodies everywhere throughout time.
WATCH OUT! In common speech, people often use the terms "theory" and "hypothesis" as synonyms. That's not the proper technical meaning of the term! When we refer to the "theory of the expanding universe," we are not suggesting that there's anything hypothetical about it. On the contrary, we are saying that the patterns of observations that lead us to conclude that the universe is expanding are so well attested that they merit the elucidation of the underlying processes governing them. In the exact same sense, when a music professor teaches "music theory," they aren't in any way suggesting that maybe music really doesn't exist.
NOTE: Sometimes the term Law gets thrown around in this context. That is also a misuse. In mathematics, maybe, there exists enough certainty to call things laws but not in science. When a scientist refers to a "law" they are usually talking about a mathematical expression of some sort (E.g. Boyle's Law, the 2nd law of thermodynamics, etc.) rather than any kind of theory.
- Overturning theories: Still, because hypotheses can be falsified, the theories to which they give rise can be overturned. The difference is one of scale. Hypotheses are falsified every day - trivial events. The falsification of a scientific theory is a big deal that gets into newspapers and history books.
Two ways to overturn a theory:
- Observation: New observations are made which are inconsistent with the theory. E.g. Einstein's theory of general relativity superceded Newton's theory of universal gravitation because it better explained several astronomical observations.
- Parsimony: A simpler theory is preferred by the principle of parsimony (= simplicity). When two or more posssible answers exist to a question, the simpler one is generally preferred. E.G. Copernicus' heliocentric astronomy superceded Ptolomey's geocentric astronomy because it was simpler. Actual observational rejection of Ptolemey's astronomy didn't come until a century later.