Everyone uses the word "science," yet most of us would be hard pressed to write its precise definition. This is disturbing when you consider how often we, as voters, are asked to make decisions on scientific issues like the funding of scientific projects and institutions or the teaching of scientific concepts in schools. Here is a modest first step to a practical understanding of the meaning of science, as understood by scientists.
The world is full of concrete facts, such as, "My car is blue." Scientists call these observations. An observation is useful to science if it is repeatable, that is if other people working independantly make the same observations under the same circumstances. (If my car looks red to you and blue to me, then those observations not repeatable.) Observations can also be called data (singular datum) or , if you prefer, facts.
When many observations are assembled, patterns are often be seen that require an explanation.
Example: The sun appears to rise in the east every day.
It is the habit of the human mind to perceive patterns whenever possible. Often, perceived patterns are illusory.
Example: Dreams are the result of our sleeping minds' struggle to recognize familiar patterns in the random nervous impulses that reach our brains during sleep.
To avoid being mislead by illusory patterns, we test the patterns we think we see using the scientific method. We start by expressing the suspected pattern as an hypothesis.
This is simply a statement about a pattern of observations whose truth or falsehood is initially unknown. Since we mortals cannot know the future, we can never say with absolute certainty that a hypothesis is "true." We could observe that I have had three blue cars in a row and hypothesize that every car I will ever own will be blue but it is always possible that the some day I will go nuts abd buy a red one. For this reason, no matter how many blue cars I buy, we can't know that the hypothesis is completely true. There are many situations; however, in which we can say with complete certainty that a hypothesis is false. For example, if I DO buy a red car, then the blue car hypothesis is definitely false and can never be resurrected. We therefore test hypotheses by attempting to falsify them, or demonstrate their falsehood. Hypotheses that consistently resist many attempts at falsification are provisionally accepted as true.
Since the only way that science has to test an hypothesis is to attempt to falsify it, it must, in principle, be possible to falsify the hypothesis. An hypothesis that can be falsified is said to be falsifiable. One that cannot is non-falsifiable.
Often, when a hypothesis has resisted falsification many times, and has been provisionally accepted as true, we begin to wonder WHY it and related hypotheses seem to be true. Scientists attempt to answer these questions by postulating general rules with universal explanatory power, called theories. Theories generally address a large range of phenomina using a small number of powerful rules.
VI. What a theory is NOT:
Popular culture mistakenly uses the words "theory" and "hypothesis" as synonyms. Think of how many times you have heard someone say, "I have a theory, but it is JUST a theory." This is just plain wrong and shows that the speaker does not understand what a theory is in the scientific sense. Just as there is nothing hypothetical about "music theory," there is also nothing hypothetical about "gravitational theory" or "evolutionary theory."
VII. The scientific method:
The sum of the activities described above is sometimes called the scientific method. There isn't a single uniform proceedure that all scientists follow. Some perform controlled laboratory experiments to collect data, while others (such as geologists and paleontologists) rely on direct observations of the uncontrolled natural world. In either case; however, observations are being used to discern patterns, formulate and test hyotheses, and describe the large scale processes that underlie them in terms of theory.
The process of describing the material universe, including its components, history, and the processes acting within it, by means of observation and hypothesis testing.
John Merck, 1999.