Post No.: 0034
Please understand the differences between a hypothesis, fact, theory and law when talking in scientific contexts and when reading science news…
A hypothesis is the starting point of any original scientific experiment or study – it’s a statement that is testable and falsifiable (i.e. it must be possible to prove that it’s false), so that we can prove if it’s (statistically likely to be) true or false (e.g. dogs have dreams every time they sleep).
A fact is just an observation, a data point (e.g. this cat hurled out two hairballs on the carpet today).
A theory is a statement that is testable and has repeatedly been proven to be the most true via the preponderance of empirical evidence gathered via the scientific method so far, particularly when compared to competing proposed theories. This term is probably the most misunderstood because in general everyday usage a ‘theory’ is used to mean something merely speculative, but in scientific contexts it means something far more supported and proven. A theory is the best explanation for a set of observed phenomena that we have, at least so far (although different scientists may dispute which theory is the strongest in contentious cases in their fields). Its strength is based on its predictive power (e.g. the theory of evolution, which still occurs right now wherever you live and however you live, whether governments or corporations intervene or not, whatever medical science brings or not, etc.).
And a law is a descriptive statement of how nature will behave under specific conditions. Again it is tested and has repeatedly been proven to be the most true via the preponderance of empirical evidence gathered via the scientific method so far. The difference between a theory and a law is that theories attempt to explain causally why (not ‘meaning’ or ‘purpose’ why but ‘mechanistically’ why) a phenomenon exists and a law just describes what is observed. A common misunderstanding is that scientific laws are stronger, upgraded versions of scientific theories but they are different things – theories are broader in scope, whilst laws are more concise to the point they can be practically used to make concrete predictions, hence laws come in the form of rules, equations or formulae (e.g. Newton’s laws of motion, at least when objects are not approaching the speed of light). Please note though that some ‘laws’ aren’t really scientific laws at all (e.g. Murphy’s law or Sod’s law).
I also want to note here that the words ‘positive’ or ‘negative’ in scientific contexts don’t imply ‘good’ or ‘bad’ but indicate the ‘additive’ or ‘subtractive’ direction of effect i.e. it means ‘+’ or ‘–’ in the straightforward mathematical sense (e.g. an escalating conflict involves a positive feedback effect but there’s nothing good about such a situation (except for arms manufacturers, sellers and their shareholders I suppose)). But do watch out because speakers and writers can unwittingly flip between meanings depending on what they’re exactly saying – just like when using the word ‘theory’ to sometimes mean the scientific definition and sometimes the general parlance definition. (That’s all a problem of the ambiguities present in the English language!)
More could be elaborated for each of these definitions but for most science news consumers I think this should be sufficient. The main thing is clearing up any misunderstandings you may have had.