Tim Josling wrote: Well here we differ; my view is that the question of whether a current area of study, is a science or not is simple and quite precise, depending only on whether it is consistent with the following definition. *science:*[tentatively] : An epistemological program, whose aim is verifiable knowledge; interpreted as knowledge consisting of 'objectively falsifiable hypothesis's'. where by 'objectively falsifiable hypothesis' is intended: a theory consisting of one or more 'objectively falsifiable-statements'. where by an 'objectively falsifiable-statement' is intended: a statement which asserts explicitly or implicitly , one or more 'objectively observable facts' where by 'observable fact' is intended: (a) A 'logical relationship' between defined categories, or (b) The 'enumeration of a defined category' , or (c) The 'measurement of a defined quality, of a member of a defined category, in defined units ' , or (d) The 'mathematical relationships between such defined quantities' , or (e) other unanimously agreed upon, unambiguous and operationally defined descriptions of phenomena. Commenting on the above definition 1/ Verification and falsification seem superficially to be complimentary notions; but evidence can falsify a theory absolutely; that is in a way which is not contingent on any later evidence. Whereas evidence can only verify a theory to the extent of showing// the theory consistent with it, later evidence may falsify it. 2/ Normally the number of explicitly or implicitly 'objectively observable facts 'asserted,' will be much larger, than will ever be observed, but in the degenerate case, where all the asserted facts have been observed; the hypothesis reverts to the status of a list of observed facts 3/ All 'falsifiable statements' are not be necessarily objective; and of those that are, not all are scientifically relevant; 4/ The logical consequence of the above definition would be: -scientific language itself, will be qualitatively different from other non-scientific specialist jargons, because of the constraints of falsifiability on the definitions of it's words. -scientific knowledge will contain no value judgements; ie. statements about what should or should not be; since such statements are not falsifiable. - scientific knowledge in any subject area, will consist of an: accumulating body of 'observed facts' and a number of hypotheses of variable transience, competing with each other, for consistency with the accumulating body of facts; -A logical implication of this, is that each succeeding theory, will contain the replaced theory as a special case. -scientific knowledge may or may not be quantitative; but it is necessarily falsifiable. eg “All bats are placental mammals”; is a scientific theory. 5/ The consequences of 4/ constitute a theory falsifiable against the observed history of science; that is the definition is itself 'objectively falsifiable' / 6/ A further falsifiable contention would be , that this usage would be preferred by the demographic of ' theoretical physicists'! 7/ Finally ,whilst Carl Popper should be given full credit for invention of the term 'falsifiability'; it's use here differs significantly from what he envisaged; thus it must stand or fall on it's own merits. Whereas I would see Bayes Theorem as merely a theorem which is useful for ranking quantitative hypotheses for consistency with current empirical observation That is once a particular fact has been observed and confirmed by numerous parties so we have confidence in it's value; then if one or more hypotheses predict something different; they are false . regards Rohan McLeod