http://www.talkorigins.org/faqs/evolution-fact.html

hen non-biologists talk about biological evolution they often confuse two different aspects of the definition. On the one hand there is the question of whether or not modern organisms have evolved from older ancestral organisms or whether modern species are continuing to change over time. On the other hand there are questions about the mechanism of the observed changes... how did evolution occur? Biologists consider the existence of biological evolution to be a fact. It can be demonstrated today and the historical evidence for its occurrence in the past is overwhelming. However, biologists readily admit that they are less certain of the exact mechanism of evolution; there are several theories of the mechanism of evolution. Stephen J. Gould has put this as well as anyone else:

In the American vernacular, "theory" often means "imperfect fact"--part of a hierarchy of confidence running downhill from fact to theory to hypothesis to guess. Thus the power of the creationist argument: evolution is "only" a theory and intense debate now rages about many aspects of the theory. If evolution is worse than a fact, and scientists can't even make up their minds about the theory, then what confidence can we have in it? Indeed, President Reagan echoed this argument before an evangelical group in Dallas when he said (in what I devoutly hope was campaign rhetoric): "Well, it is a theory. It is a scientific theory only, and it has in recent years been challenged in the world of science--that is, not believed in the scientific community to be as infallible as it once was."

Well evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world's data. Theories are structures of ideas that explain and interpret facts. Facts don't go away when scientists debate rival theories to explain them. Einstein's theory of gravitation replaced Newton's in this century, but apples didn't suspend themselves in midair, pending the outcome. And humans evolved from ape-like ancestors whether they did so by Darwin's proposed mechanism or by some other yet to be discovered

All hypothesis begins from unfounded conjecture, only thereafter subjected first to critical preference and then to reality testing. All assertions are both opinion and claims of truth. Hence, none of the aforesaid is any disqualifier, nor is there any better alternative or real need thereof

Not ALL, by any means. There is normally some foundation, some ideas or associations which form the starting point of the hypothesis.

'Not rigorously justified' is not equivalent to 'unfounded'.

it is then a matter of working through the implications and possibilities suggested by the initial inspiration into a form which is reasonably consistent with other theories and facts, and that can be tested.

'Critical preference'? What is that supposed to mean? Critical examination and testing, yes, but 'preference'?

There has to be a minimal foundation, accepted set of facts, otherwise you cannot form a meaningful hypothesis - it has to be a hypothesis about something, an attempt to explain some gap in our knowledge, or to resolve some conflict in current theories.

Without keeping in mind the background knowledge, we have no basis for formulating new ideas.

Yes, of course we need to set aside various current assumptions and theories in order to see if better ones can be formulated. But unless you are hypothesing about the origin and nature of everything, you need to start from some established foundation or you are faced with re-inventing science, which is not what most serious speculation does.

If you are forming a new hypothesis in the field of chemistry, for example, you will be assuming at least basic atomic theory, and the Physics behind it.

Your comments about errors, and even, to an extent, on deduction, are pretty much on track.

'Internal consistency' should NOT be a matter of 'preference' it should be mandatory. 'Elegance' should not be a criterion, except perhaps in choosing between alternatives which are otherwise of similar explanatory power. 

Hypotheses have no a priori justification, nor does hypothetico deductive method employed in scientific method require a priori justification for hypotheses. And indeed, the failure or refutation of one hypothesis may inspire new and better hypotheses, but that is not a requirement, either, according to Popper. Any starting point is acceptable. Error detection and correction, follow.

BobSpence1, there is no foundation or justification, minimal or otherwise, only background context as provisional as any other hypotheses. Indeed, exactly such bias is inevitable, in order for anything more to be intelligible, and not avoided a'priori but only subject to ongoing error detection and correction as any and all other hypotheses.

nigelTheBold, I hope you won't mind, I made use of your PZ Myers quote, here: http://www.atheistthinktank.net/thinktank/index.php?topic=8103.msg157089#msg157089 

I think in general the population of the US doesn't understand the word 'theory' in the scientific use of the word.

Christian apologists DO however know the word and I think that in many cases they are purposely equivocating to muddy the waters

and make it appear that they can dismiss the theory of evolution as somehow weak or unproven.

I think "knowledge" is more deserving of being "avoided like the plague" in serious discussions, because it really is just a form of belief, at one end of the spectrum with something like wild speculation or guesswork near the other end.

The common, and stupid, 'definition' of 'knowledge' as 'justified true belief' is getting close to recognising this FACT, but renders itself hopelessly nonsensical by including the word 'true' in there.

My reaction to the article is not entirely facetiously summed up in a slight variation of the title - 'Metaphysics' is for Dummies.

EDIT: To the extent that Metaphysics refers to something useful, I prefer to stick with 'Philosophy of Science', as having less medieval baggage hanging off it.

 We can never be a"aware of truth" as such, only of the degree to which a theory corresponds with our current perception of reality. This is all we have, not "truth".

EDIT: Of course there is a serious problem with "justifiied" as well, but 'true' is what massively begs the queation, or turns that definition of 'knowledge' on a hopelessly circular thing.