What is science?
The practice of science is divided into two great realms: Observation of the world around us, and explanation of the phenomena we observe. Some scientists do mostly or exclusively observation. Others propose and test theories. More about “testing” theories later.
Observation
This realm of science requires direct observation. It takes many forms as evidenced by the number of terms we use to describe the observations: phenomena, data, measurements, properties, evidence, laws.
Explanation
This realm of science invokes theoretical mechanisms which we cannot observe directly to explain the phenomena we can observe. It often takes one of three forms: hypothesis, theory, and model. There may be several reasons we cannot observe the mechanisms directly (too small, too big, too slow, too fast)
Each of these kinds of Observations and Explanations will be considered further in later chapters, but a few examples will be useful here:
For centuries humans have observed some very strange rocks shaped like animal bones and teeth, insects, plant leaves, even eggs and footprints. Many of these have been measured, catalogued, classified, and studied endlessly. All of that falls into the realm of observation. Of course, immediately upon discovering these “fossils” humans proposed hypotheses to explain their existence (Theories: God put them there or species evolved).
When early chemists started doing careful measurements (weighing everything in sight) they discovered that the total mass in any system was always the same before and after a chemical or physical change. They formulated a Law called the law of the conservation of mass. (A Law is just a summary of lots and lots of observations.) They also proposed hypotheses to explain why mass is always conserved (Theory: All mass is made of unchangeable atoms).
Early astronomers observed that all the heavenly bodies move across the sky from east to west. They also observed that most of them stayed in fixed position relative to each other night after night (called stars), but that a few of them changed their positions relative to the fixed bodies and to each other each night (called planets, or wanderers). They also proposed explanations for all this data. (Theory: The planets are attached to separate huge spheres that rotate around the earth independently of the sphere that all the stars are attached to.)
Early humans observed that different people behaved differently. They proposed explanations.(Theory: The way people behave is controlled by the stars they were born under.)
You can probably think of many, many, many other examples of observations made by scientists and everyday people. Some of them may not require explanations (theories). You may or not have theories to explain the observations. A lot of the fun of science is coming up with explanations, then trying to decide what evidence you need to suppport or refute your theory.
Question: Can a theory ever be proven?
I want to say no, a theory can't be proven, but if we can directly observe a mechanism, isn't that the same as proving it? That is, we assume our observations are correct. For an example, if there were some kind of machine that produced something, but we couldn't see its insides, then we could formulate a theory of what it is doing. But later, maybe we can figure out how to get inside the machine with a shrink ray or something, so it becomes directly observable. I suppose you could argue that it is possible that our observation or entrance into the machine may have changed the mechanism, but that hardly seems reasonable. Though, I suppose that is what makes a theory technically unprovable.
ReplyDeleteYou're right about getting inside the machine. In fact Dr. Schaefer made a sealed wooden box with strings coming out two little holes, The strings obviously interacted inside the box somehow. When one was pulled the other got shorter (sometimes) but not by the same amount. The strings were attached to springs, pullies, etc. inside. The challenge was to derive a "theory" of what was inside the box to explain your observations. So I said "OK, now we take a saw to it and actually observe the mechanism. Is it still a theory? He said "Well, that's where the analogy breaks down." But I don't think so. I think that's an example of technology advancing to the point where we can observe what was previously unobservable. In that case, it's not a theory anymore. It becomes data, observation, measurement.... That happens all the time in Science. Can you think of a case where what had been theory became directly observable? (Anybody, not just Jeff.)
ReplyDeleteThe obvious example seems to be the motion of the planets, which we can now watch by going into space. It's a cosmic machine, I suppose, like Newton and Leibniz were so fond of arguing about.
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