Scientific theories

A topic in  Learners' conceptions and thinking

A common alternative conception is that a theory is something which has the same status as a guess, opinion and hypothesis.

Learners often think that when theories are tested, science can prove them, in which case they are factual, so no longer theories. They may become seen as laws (Taber, et al, 2015).

Student understandings of scientific epistemology were generally simplistic. For most interviewees theories were just ideas, until they were proved to be correct.
Student understandings of scientific epistemology were generally simplistic. For most interviewees theories were just ideas, until they were proved to be correct. (From Taber et al, 2015)

To scientists, a theory is more than just an isolated hypothesis: rather they are 'consistent, comprehensive, coherent and extensively evidenced explanations of aspects of the natural world'.

Many theories are supported by extensive evidence, and sometimes the evidence is so overwhelming (the theory of natural selection, for example) that many scientists come to consider the theory to be an accurate account of nature. However:

  • strictly a theory (and indeed scientific knowledge in general) is conjectural, not factual;
  • so although scientists may provisionally commit to a theory as the basis for developing their work, they should not 'beleive' in a theory
  • but a theory has to be more than just a guess (unfortunately in everyday language 'theory' may mean no more than an idea) as it has to be supported by arguments from other theories and/or evidence;
  • a theory is never 'proved' in the sense that theorems can be proved in mathematics – in principle, all theories are open to being overturned by new evidence or new ways of thinking bout evidence
  • a law is not a proved theory – a law is a specific generalisation from observations
  • a theory may explain or incorporate one or more laws

Some student comments:

Work cited:
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