Originally posted by vistesd
Thanks, DT. With all that, if an observation (or set of observations) turns out to be incorrect, do you say that the facts were wrong--or that the observations did not accurately reflect the facts? My question has to do with how those two terms are commonly used in scientific (as opposed to philosophical or mundane discourse)--before the level of hypothesi ...[text shortened]... y a priori constraints--but that might just have been a function of the kind of research he did.
First, I don't think the word "fact" has any special meaning in Science that it does not have in other fields. Second it's not a word scientists use particularly, certainly no more than any other group - they'll talk about experiments, evidence and so forth, but will rarely talk about a "scientific fact" - certainly not when discussing their work with each other. I think the two groups of professionals who use the word "fact" most are lawyers and politicians, the word tends to have more of a rhetorical purpose than a descriptive one so it's more important to fields which involve rhetoric. When it is used in Science it has the same meaning as in ordinary usage.
According the the Oxford online dictionary, the etymology is as follows:
Late 15th century: from Latin factum, neuter past participle of facere 'do'. The original sense was 'an act', later 'a crime', surviving in the phrase before (or after) the fact. The earliest of the current senses ('truth', 'reality' ) dates from the late 16th century.
So the word comes from law and, except for the "after the fact" sense, won't be used in science any differently to the way it is used in law.
I was trying to think what it is about a fact that makes it a scientific fact and not just any old fact. Since a fact is a statement about the world and science makes statements about the world all facts would seem to be scientific. The adjective scientific must therefore refer to the fact that the fact is true in order to be a fact. So, it must be that the fact has undergone a truth test that is scientific - which in science would be an experiment. So in the event that "fact" has any distinct meaning in science it is simply to do with the verification method.
What happens when the facts change? A little over half a century ago they had worked out the age of the universe and it came out to less than the age of the Earth. Clearly something was wrong. It turned out the problem came because there were two types of Cephid variable. A Cephid variable is a kind of star that changes in brightness over time. The absolute magnitude of the star depends on the rate of pulsing, which makes Cephid variables useful as standard candles. Because this relation is different for the two and that was not taken into account the estimate for the age of the universe was too small and fortunately obviously so. In that case there was a fact missing, which threw out the result. The result (that the Earth is older than the Universe) was never
mistaken for a fact because it was clearly faulty. But had it been then it would have been revealed as a false fact.
The truth test for an actual experimental data point is just whether we trust the experimenter to tell the truth and perform their experiment competently. The result isn't really certain until the experiment has been repeated by more than one group, which cuts out bad results due to bad experimental design, general incompetence, and fraud. So, except that scientists do not present their results under oath but have a different system to avoid deliberate falsehoods, the truth test for whether the raw data is true is not really any different to the one used in a trial - the witness is assumed to be trustworthy until their evidence is contradicted by someone else's or there is some evidence that they are not.
So, I think that the word "fact" has the same meaning as in philosophy and ordinary usage. When facts turn out to be wrong, as can happen, then the old facts are no longer viewed
as facts and the new facts replace them. Formally the old facts weren't ever facts. Because we live with imperfect truth tests, and natural languages are loose, scientists like any other group, will talk about facts being wrong. This is just an informal usage of the word fact. What they really mean is that the old statements were mistaken for facts, but in fact were not.
Scientists observe objects and their phenomena, they do not observe facts. A fact is a sentence and cannot be observed, the thing the fact is about is what is observed, unless one counts reading it as observing a fact. If a scientist claims to have observed a fact it is because the word has no specific technical meaning in science and so scientists are as likely to be as hazy about the correct meaning of the word as any other group of people.