We see these "only a theory" type remarks all the time. They are generally addressed in each thread, but it seems that a standalone thread is warranted. Whenever I see these remarks it is immediately clear that the author does not understand how the words are used in the scientific community. If you prefer to watch than to read, jump to the video at the bottom of the message. Facts are observations -- they have no explanatory power. The sun rises in the east and sets in the west. The eastern coastline of South America matches the western coastline of Africa. Simple life forms appear in the geologic column before more complex life forms. Hypotheses are testable/falsifiable statements that explain the known facts. Geocentrism was a hypothesis before becoming a theory. Plate tectonics was a hypothesis before becoming a theory. Evolution was a hypothesis before becoming a theory. Theories are built on confirmed hypotheses and explain a large body of facts. Theories are not hunches or wild guesses as the term may be used on the street. Theories are built on enough evidence that a single anomalous data point is unlikely to falsify the theory, though it may require a revision to the theory. Theories do not aspire to becoming laws. Not all fields of science even use the terminology of "law". When "law" is used, it is a generalization of behavior (or equation(s)) within the framework of a theory. There is no subsequent term for a theory that is massively supported by evidence. The example that everybody loves... within biology, even though evolution is supported by a metric arse load of evidence across multiple disciplines, it will always be a theory, it will not be described as the law of evolution. Heliocentrism replaced geocentrism when there became enough data to falsify geocentrism. Theory of plate tectonics. Theory of evolution. Big Bang theory. Germ theory. Atomic theory. Here are a few scientists discussing how the terms are used among the scientific community. [ame="http://www.youtube.com/watch?v=g7Ctl9nzEqs&feature=player_embedded"]Just a theory?[/ame] Wanna kill these ads? We can help!