A. Let's start by defining terms. This is what the Free Dictionary says about science (1st meaning only):
1. a. The observation, identification, description, experimental investigation, and theoretical explanation of phenomena.
b. Such activities restricted to a class of natural
phenomena.
c. Such activities applied to an object of inquiry or
study.I will restrict myself to meaning 1a, actually. How does science differ from three other honorable enterprises, namely the study of history, performing music, or working as a check-out person in a grocery store?
The study of history usually can't involve experimental investigation. You can't see what would have happened if George Washington hadn't crossed the Delaware, for example. You can guess, and your guess may be right, but you can't know. But you can experiment in science. You can find out what happens if someone takes their medicine every other day, rather than every day.
Music performance doesn't involve much identification (in that you are classifying something, such as rock types or species of grasses) and description, nor theoretical explanation. It may involve experimentation, though.
Grocery checkout persons don't do much identification, either, except what's already done for them in the bar codes on items. They may experiment, however, for example by smiling at some customers and not at others, but the amount of experimentation is limited. If they start only charging for every other container of milk to compare it with customer satisfaction, or giving more change that the customer is supposed to get, they'll get fired.
B. The controlled, replicable experiment, then, is one of the cornerstones of much science. Granted, even scientists can't experiment on everything. Historical geologists can't manipulate history any more than history professors can. Astronomers can't manipulate stars or galaxies. Where direct experiment isn't possible, most scientists may compare experiments, as it were, that nature has already provided. For example, how does the light from different stars, in different regions of the universe, compare?
A controlled experiment is one wherein, ideally, one property, and only one, is varied between groups, and everything else is the same. For example, you might test inbred fruit flies, all in the same environment, giving one a vitamin supplement, and one no such supplement, and compare their fertility. (It is usually impossible to make the environment absolutely identical for every organism, or for different attempts at the same experiment. Even inbred strains may have a little genetic variation.)
Replicable means that someone else can test what you have done, by trying the same experiment.
I understand that there is debate about how science really works, but I'm going to ignore it. See the Wikipedia article on "Science" for an introduction to this.
C. Science is clearly important. Think of social media, energy use, and ballistic missiles. The products of science, often called technology, are also important.
The previous sentence mentioned three important topics. None of them is a strictly scientific topic. All of them have legal, political, ethical, economic and even religious implications. That's true of most or all of the technological products of scientific work. If a scientist, for example, says that she is opposed to allowing illegal immigrants to get driver's licenses, or that human embryos can ethically be destroyed in the process of stem cell research, what she says on one of those subjects should carry no more weight than what a grocery clerk says, unless she is a legislator, in addition to being a scientist.
Sometimes scientists think that they are making scientific statements, but they aren't. They are merely scientists making statements, not making statements that are backed up by controlled, replicated, experiments. Watson and Crick, for example, claimed that they had discovered the secret of life, when they proposed the double helix. They had made an important contribution, but they hadn't discovered the secret of life. They hadn't explained how DNA came to be so central to living things in the first place. They hadn't given an explanation for how the information in DNA comes to be expressed (we now know a lot more about that, partly because of the work of Crick, himself.) Both of them, apparently, thought that they had ruled out any supernatural explanation for living things. But they hadn't. God could have created life with DNA as its main information carrier. I don't believe any experiment can rule that out (or prove it.) Hebrews 11:3 says "By faith, we understand that the universe has been framed by the word of God, so that what is seen has not been made out of things which are visible." God could have somehow written His signature in DNA, or in rock layers or clouds, or in astronomical objects, but He didn't. Or did He? The believer can and does see God's handiwork in all of these. The non-believer doesn't. We can choose to believe, or not to believe.
D. I don't want to leave the impression that science gets a better and better picture of how nature works only by doing experiments. As Thomas S. Kuhn pointed out, scientists get such a changed picture by new ways of looking at the world -- adopting a new paradigm. What experiments scientists do is determined by how they view the natural world. Galileo wouldn't have done any experiments on radio, because he didn't know there was such a thing. Newton didn't discover gravity. But he did (perhaps after watching an apple fall) realize that gravity could be explained as an attractive force. This wasn't because of any experiment that he did. The experiments came later.
This is a re-post, slightly modified, from a post of mine on December 11, 2006. Thanks for reading.
