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Author Topic:   What is a theory in biology?
ProfessorR
Inactive Member


Message 1 of 22 (204612)
05-03-2005 10:20 AM


Dear group,
Recently, I had an exchange with a member of this forum who, discussing intelligent design, said that there is no such thing as the theory of evolution. If I understand him correctly, he thinks that biologists, as opposed to other scientists (e.g., physcists) lack some essential elements of training in scientific method and, therefore, misunderstand the term "theory."
In this regard, may I ask, what really is a theory in biology?
Here is my thought on it (please note that I am a researcher-experimenter and, more recently, a university biology teacher but not an expert-professional in the scientific method, philosophy of science etc.). I understand theory in biology as an unusually interesting and daring hypothesis with a broad scope and interest to all biologists, regardless of their narrow field of study. Like any hypothesis, a theory is a human statement (or a set of statements) that is, essentially, a "guess" trying to explain certain natural phenomena. However, UNLIKE most hypotheses, a theory is a statement or a set of statements that provides an explanatory framework to *life* in general (while most hypotheses in biology are guesses trying to explain only certain manifestations of life).
If this understanding of a theory is anywhere near truth, then the theory of biological evolution - which, essentially, states that life as we know it is being constantly diversified because of the constant action of factors like mutation, natural selection, genetic drift, gene flow, and other suchlike factors - is, actually, a true theory. So are such theory as the chromosomal theory of heredity or the cellular theory. On the other hand, hypotheses that are concerned with particular manifestations of life are not theories, even if they are extremely interesting and daring; for example, Burnet's hypothesis of clonal selection or Jerne's network hypothesis are not theories, because they do not address phenomena outside of just one manifestation of life (the ability of some life forms to mount immune responses).
I will be very grateful for all your insights.
Best wishes,
Richard

Replies to this message:
 Message 3 by mick, posted 05-03-2005 12:29 PM ProfessorR has replied

  
ProfessorR
Inactive Member


Message 4 of 22 (204736)
05-03-2005 5:46 PM
Reply to: Message 3 by mick
05-03-2005 12:29 PM


Mick, thank you for your excellent comment. I did not know that the use of words "hypothesis" and "theory" has such a long history an that these terms were sometimes used in a context and with meaning very different from the currently conventional.
Also, I think it's an exellent point that a theory differs from a hypothesis in that a theory can by itself generate new hypotheses, while a hypothesis can only be tested.
Would you care to comment on the statement that "Darwinism" (or the modern theory of evolution) is not a scientific theory? What, in your opinion, makes people issue such a statement?
Thanks a lot again, and my best wishes,
Richard

This message is a reply to:
 Message 3 by mick, posted 05-03-2005 12:29 PM mick has replied

Replies to this message:
 Message 5 by mick, posted 05-03-2005 6:31 PM ProfessorR has replied
 Message 9 by New Cat's Eye, posted 05-03-2005 7:28 PM ProfessorR has not replied

  
ProfessorR
Inactive Member


Message 6 of 22 (204748)
05-03-2005 6:50 PM
Reply to: Message 5 by mick
05-03-2005 6:31 PM


Mick, thanks again. Actually, I think evolution can be viewed as a fact (or as an observation). If we define biological evolution as a change in the genetic makeup of populations, than it IS a fact, or, if you will, such change HAS been directly observed. On the other hand, there is something that I believe to be a scientific theory, called "the theory of evolution." It states that life has been diversified and continues to be diversified due to evolution (see the definition of evolution above).
Another question. What if we ask authors of those infamous textbook stickers - just why do you guys concentrate on evolution? Let chemistry textbooks contain stickers that say, "atoms and molecules are a theory, not a fact" (indeed, who saw them?). Let physics textbooks have stickers that say, "Electromagnetic field is a theory, not a fact," etc. etc. etc. Why evolution?
Richard

This message is a reply to:
 Message 5 by mick, posted 05-03-2005 6:31 PM mick has replied

Replies to this message:
 Message 7 by mick, posted 05-03-2005 7:16 PM ProfessorR has replied
 Message 10 by Dead Parrot, posted 05-03-2005 7:40 PM ProfessorR has not replied
 Message 12 by RAZD, posted 05-03-2005 7:49 PM ProfessorR has not replied

  
ProfessorR
Inactive Member


Message 8 of 22 (204754)
05-03-2005 7:19 PM
Reply to: Message 7 by mick
05-03-2005 7:16 PM


Mick, okay, I stand corrected...

This message is a reply to:
 Message 7 by mick, posted 05-03-2005 7:16 PM mick has not replied

  
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