Definition of Science - Island of Sanity

Island of Sanity


Definition of Science

What is "science"?

The scientific method

Historians of science generally agree that "science" as we understand it today was first clearly defined by Roger Bacon in his book Opus Majus in the year 1267.

Bacon described the scientific method as consisting of a cycle that goes like this:

  1. Hypothesis. Propose a hypothesis, a theory, some idea about how you think the universe might behave under a specified set of conditions.
  2. Experiment. Plan and carry out some experiment to test if the hypothesis is correct.
  3. Observation. - Observe the results of the experiment. Did the universe indeed behave as you thought it would, or did something different happen?
  4. Evaluate hypothesis. Confirm, revise, or reject the hypothesis and return to step 1.

Let's illustrate this with a simple example:

  1. Hypothesis: There is a force, let's call it "gravity", that causes objects to fall to the earth.
  2. Experiment: Take a rock, hold it at arm's length, and release it.
  3. Observation: The rock falls to the earth.
  4. Evaluate hypothesis: The hypothesis is confirmed.

This is, of course, a trivial example. You might not even think of it as much of a "scientific experiment", as the results were so familiar and obvious. But it illustrates the important point. If we had, in fact, observed that the rock hung motionless in mid-air, or flew upward, then we would have had to reject the hypothesis.

But wait! Let's try another experiment:

  1. Hypothesis: The same: objects fall to the earth.
  2. Experiment: We travel to the moon. While standing on the moon's surface, with the earth visible in the sky above, we hold a rock at arm's length and release it.
  3. Observation: The rock does not fall toward the earth, but rather toward the surface of the mooon.
  4. Evaluate hypothesis: The hypothesis is inadequte. When we're on earth objects fall to the earth, but when we're on the moon objects fall to the moon. Can we generalize this? Perhaps objects fall toward the surface of whatever planet or planet-like body we are on. But how big does something have to be to be a "planet"? Etc.

For the scientific method to work, the scientist must not become too committed to his theories. He should always be ready to modify or abandon a theory that doesn't hold up. Indeed, a scientist will often put forward a theory with zero commitment: If he really doesn't know what to expect, he just makes something up and watches what happens.

The uniqueness of science

Note that science is quite different from almost all other areas of human knowledge in this very important way: In science, it is possible to declare questions settled and closed to a degree far beyond what is achievable elsewhere.

Compare science to politics. People debate how to create the ideal government. But ... the ancient Greeks and Romans debated pretty much the same points that we debate today: How do we prevent power from corrupting those who hold it? How can we give the government enough power to prevent citizens from robbing and killing each other without the government having so much power that it is a greater danger than the thieves and murderers? etc. Many answers have been proposed over the centuries, but we would be hard pressed to say that any of these questions have been resolved.

But now consider the scientific questions that the ancient Greeks and Romans considered. What is matter ultimately made of? Could there be some basic particles called "atoms" that make up everything? Today we know the answer is "yes". Does the earth move around the sun, or does the sun move around the earth? Solved. What are the functions of the various bodily organs, the kidneys, the brain, the liver, and so on? Largely solved. Et cetera.

Similar things could be said about history: The primary way to know what happened in the past is to read the accounts of people who were there. But these are often missing or incomplete, or written by people who have obvious biases making it impossible to know whether they are being completely honest. So how can we ever know for sure?

Philosophy? Ethics? The same debates go around and around, seemingly forever. But science answers questions and moves on.

This distinction can be over-emphasized. Science often makes mistakes. New knowledge often makes it apparent that previously "settled" theories were only approximations of reality. There are no truly closed and settled questions in science, either. But perhaps we can at least say that, while science cannot declare some statement to be the absolute, final truth, at least it can routinely say that some statements are wrong, discard them and move on.

An implication

An important implication of the scientific method is that a scientific theory must be capable of producing testable hypotheses; it must have "predictive power". That is, for a theory is truly scientific, we must be able to devise some experiment where we can say that if the theory is true, than X will happen, and if X does not happen, the theory must be flawed.

For example, not long ago I read about a psychic who claimed that beings from another planet were sending him messages by telephathy. Can we formulate a scientific theory about this claim? Probably not. The psychic freely admits that only he can hear the messages. There are no conditions that we know to create to enable anyone else to hear the messages. We could ask him to ask the aliens to describe their planet, but ... He claims that they are from a planet in another solar system, so, given our present technology, we have no way of knowing much of anything about this solar system independantly of the psychic's claims. If he could actually identify the aliens' home system with a star known to us, perhaps there are some general things about it that we can know to test the statements supposedly made by the aliens. But if he's just making all this up to get on television (the obvious alternative theory), he could have just read a little astronomy and avoid contradicting any known facts. If we ask him a question he didn't study up on, he can just say that he's asked the aliens about that and they haven't replied yet. Even if he made a mistake, he could always claim that it is our astronomy that is wrong, the aliens know more than we do. Et cetera. We could go around and around such claims forever. It is unlikely that there is any experiment we could perform to prove his claims true or false.

Is the opposite of "science", "falsehood"?

Note that none of the above proves that the psychic's claims are false. They are just not science. Personally, I consider his claims very unlikely, not because of any scientific arguments, but simply because from what I know about human nature and the nature of the universe in general, I think it more likely that someone would make up a story like this for publicity and money than I think it likely that aliens would really be able to communicate with us in such a way and would choose this particular person as their spokesman.

There are many theories and claims that people make that are probably true but that cannot be tested scientifically.

For example: Beethoven's 5th symphony is a better piece of music than that little ditty about the principal that my 8-year-old made up. This is surely true, but I cannot imagine how we could actually test such a statement experimentally. I suppose we could play both for a large number of people and take a vote, but that wouldn't really prove which was better, merely which was more popular. Perhaps we could devise objective ways to measure the consistency or complexity, but again, that wouldn't prove which was better, just which was more consistent or complex. So the statement is unprovable in any scientific sense, but nevertheless true.

Thoughts like the above often lead people to think that the opposite of "science" is "wacky stuff" and "opinion", but this isn't really true either. There are many statements that we routinely consider "hard facts" that are not science.

Example: Julius Caesar was emperor of Rome. This is surely true. As historical facts go, there is overwhelming evidence for it. But it is not a scientific statement, because there is no experiment we could do to prove or refute it. How could we? Caesar has been dead for over 2000 years. What test could we perform? It is a historical statement, not a scientific statement.

Similar things could be said about statements of politics, philosophy, religion, and so on. Most of the statements made in such fields are not science, but this is not a synonym for "false". It simply means they must be investigated by other means.

Science and pseudo-science

There are many ideas and theories today that are called "science", but have little to do with actual science.

Let's get back to the definition. Science is about experimentation and observation. Common mis-definitions of science include:

Ideas expressed in mathematical or other technical-sounding language. Astrologers draw elaborate charts to illustrate their theories. They are meticulous in the accuracy of their measurements and in their calculations. They claim this makes astrology a science. It doesn't. For astrology to be a science, they would have to show experiments demonstrating that predictions based on astrology are measurably more accurate than random guesses.

Ideas expressed by scientists. The news media routinely present reports where they say, "science has found that ..." and then quote someone whom they describe as a scientist. But just because something is said by a scientist doesn't make it science. Just because a certain scientist likes vanilla better than chocolate doesn't mean it is a scientific fact that vanilla is better than chocolate. Before you accept that something is scientifically proven just because someone who calls himself a scientist said so, ask, What experiments were performed and what were the results? Could other theories also explain these results? Also, when someone is trying to convince you that a certain political or social policy is necessary, remember that any "scientist" they quote is not necessarily even representative of the concensus view of all scientists: it is quite possible that they picked someone who would say what they want people to hear.

Scientism. There is a philosophical idea that only ideas that can be proven scientifically are true. If they took this literally they would have to reject history, mathematics, and much of what we say about art. But more often they limit their discussion to rejecting religion and the supernatural. Scientism is typically characterized by statements that they do not believe in God or the afterlife because these things have not been proven scientifically, and that the human soul or mind is purely a function of presently-known physics and chemistry. Of course, no experiment has ever been conducted that proves that there is no afterlife, or that there might not be forces or processes in the universe unlike anything we presently understand through science. While scientism claims that we can only believe what we can prove by scientific experiment, they have never offered any experiment to prove that the theory itself is true. It is simply an idea that some people believe because it appeals to them philosophically.


Of course, no invention as big as science itself is likely to be entirely the product of one man's efforts. Bacon himself credited predecessors, most notably Aristotle, for understanding the importance of experiment. Bacon's important contribution was that he was the first to clearly put together the idea that experiments should not simply be performed at random: that it is most productive if you first put forward some hypothesis, then design an experiment specifically to test this hypothesis.

Some side notes on Roger Bacon's books

Roger Bacon is best known for three books: Opus Majus, which is Latin for "big book"; Opus Minus, Latin for "little book"; and Opus Tertium, Latin for "third book". Bacon was a brilliant educator and philosopher of science, but he was apparently not particularly creative in coming up with titles for his books.

Opus Majus is mostly remembered today for its description of the scientific method, as noted above. This comes in a section in which he calls for a number of reforms in education and scholarly study. Other topics Bacon discussed in this book include his own theories (and experiments!) on light and optics, the relationship of mathematics to science, an explanation of how all science is ultimately founded on the Bible, and a call for more Bible study, especially in the original languages rather than in translation.

© 2004 by Jay Johansen


Owais Jul 23, 2014

You could pick among several dernefift hypotheses. Some examples:Will more holes in the bottom of the hovercraft make it float higher off the ground?Will a larger engine make the hovercraft float higher off the ground?Will lighter materials make the hovercraft float higher off the ground?The answer to the last two are easy (probably yes) but you get the idea. You can come up with other hypotheses that might be better.

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