Evolution is just a Theory
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[edit] Introduction
A very common evolution misconception is that it is just a theory. This misconception is quite simple to explain: the layman's use of the word "theory" is in a different context from how scientists use the term.
[edit] Discussion
The layman's meaning of the term "theory" tends to be synonymous with a hunch or a guess (such as "I've got a theory..."); it also seems to imply uncertainty (as expressed in the phrase "it's a theory, not a fact").
However, the scientific meaning of a theory has a more precise and mechanical definition: "An extremely well-substantiated explanation of some aspects of the natural world that incorporates facts, laws, predictions, and tested hypotheses" [1]. Clearly, when scientists use the term "theory of evolution", they really mean that evolution is a large body of consistent, well-substantiated facts, laws, predictions, and observations that describe natural phenomena; they don't use the word to imply that evolution is yet to be proven.
There is a popular misconception that a theory must be proven, then it becomes a fact or a law. However, a scientific theory is, most generally defined, a large body of facts and laws, so this criticism does not make sense.
The weakness of the "just a theory" criticism becomes obvious because in light of other well known theories, such as Einstein's theories of Relativity, atomic theory, germ theory, quantum theory, electromagnetic theory, plate tectonics theory, etc. No one would seriously imply that any of these theories are unproven and uncertain.
[edit] Quotations
- Theory: In science, a well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypotheses. --- US National Academy of Sciences [2]
- "Theory" means a logical, tested, well-supported explanation for a great variety of facts. --- National Center for Science Education, USA [3]
- Theory: A scientifically testable general principle or body of principles offered to explain observed phenomena. In scientific usage, a theory is distinct from a hypothesis (or conjecture) that is proposed to explain previously observed phenomena. For a hypothesis to rise to the level of theory, it must predict the existence of new phenomena that are subsequently observed. A theory can be overturned if new phenomena are observed that directly contradict the theory. --- NASA[4]
- Scientific theories, like evolution and relativity and plate tectonics, are hypotheses that have survived extensive testing and repeated verification. Scientific theories are therefore the best-substantiated statements that scientists can make to explain the organization and operation of the natural world. Thus, a scientific theory is not equal to a belief, a hunch, or an untested hypothesis. Our understanding of Earth's development over its 4.5 billion-year history and of life's gradual evolution has achieved the status of scientific theory. --- American Geophysical Union [5]
- A theory in science, such as the atomic theory in chemistry and the Newtonian and relativity theories in physics, is not a speculative hypothesis, but a coherent body of explanatory statements supported by evidence. The theory of evolution has this status. --- American Intitute of Biological Science [6]
- Evolution is both a scientific fact and a scientific theory. --- The Paleontological Society [7]
[edit] Where the Word "Theory" Does Not Apply
Very often, when a evolution is criticized for being "just a theory", it is paired along side Intelligent Design theory - the implication is clearly that, both being nothing more than "theories", they both must be on the same level of credibility.
Of course, we know this is not true, because to say that evolution is a scientific theory implies that it is rigorously tested and well-substantiated.
On the other hand, Intelligent Design is not and could never be considered a scientific theory: Intelligent Design adds no new knowledge to the world, postulates hypothetical unfalsifiable entities, cannot be described in terms of scientific laws or mathematics, and cannot be falsified even in principle. It cannot be studied, tested, empirically verified, or even have the scientific method applied to it.
Quite literally, Intelligent Design is as much of a scientific theory as Last Thursdayism (the "theory" that the universe was created Last Thursday with an apparent old age).
[edit] Related Terminology
It is helpful to understand the scientific meaning of words:
- Observation: Anything you see, hear, smell, taste, or touch, with or without special instruments, is an observation
- Hypothesis: a testable statement about the natural world that can be used to build more complex inferences and explanations.
- Experimentation: the process of testing a hypothesis by collecting data under controlled, repeatable conditions
- Fact: when an observation is confirmed repeatedly and by many independent and competent observers, it can be regarded as a fact.
- Law: a descriptive generalization about how some aspect of the natural world behaves under stated circumstances. Very often, laws are expressed in terms of mathematical relationships (see the equations for Boyles Law, Ohms Law, Snells Law, etc.).
