In Mach, of course. we have a classic case of this abusive empiricism. It is a case that also exemplifies a characteristic tendency. a kind of Nemesis, of what we might call "hypercritical" philosophic theories-theories that lay down methodological standards or criteria which are actually impossible to practice. The tendency is to lose, at crucial junctures. basic critical control of the conceptual process.--Howard Stein (1977) "Some Philosophical Pre-History of Relativity," 14.
This time I quote Stein's judgment on Mach not to discuss the varieties of empiricism (recall), despite Stein's tempting characterization of 'abusive empiricism.' (Stein's searching, critical treatment of Mach's famous criticism of the bucket experiment is deservedly legendary.) Rather, in Stein Mach is exemplarary of a certain kind of philosophical (and scientific) vice. Amusingly, Stein diagnosis an analogous vice in historiographic practice:
For the avoidance of anachronism, it is neither necessary nor sufficient to restrict one's conceptual vocabulary to that of the period under discussion. To impose such a restriction is to inhibit flexibility of thought without any important compensating guarantee against error. It is an intellectual stratagem analogous to that of the shallow empiricism in science, that seeks security in rules for the construction of concepts, and achieves only a hobbling of theory. Stein, 14.
It is hard to read (or re-read) Stein's paper and not be struck by the live possibility of intellectual decline even in a topic -- discerning the structure of nature guided by developments in physics -- where the underlying science is advancing. (Thus, reminding us, that philosophy is not easy.) Despite lacking an adequate mathematical vocabulary,* Huygens and Newton are exhibited as having surer footing in their conceptual analysis than many that have followed them (through the nineteenth century) as well as those with a higher philosophical reputation (e.g., Leibniz). Stein's historical account is not exhaustive, but the point about the decline in insight can be defended.
Stein is not a declinist; he makes no claim that intellectual decline is necessary, or to be expected. Moreover, decline is not inevitable (in Stein's account Riemann and Einstein recover lost insights). Stein's diagnosis of the source of decline is what may be call ideological; later thinkers lose the secure path because they end up in the grip of intellectual commitments that block insight.* In addition to Newton's tendency at terseness in expression, we can add lack of transparency as a further reason in the case that Stein describes; not all of Huygens most insightful observations were fully available to later thinkers buried as they were in notebooks and correspondence.
Of course, if absent, say, the inquisition, general economic depression, warfare, inadequate scientific education, one age can decline on a certain metaphysical reflection (and the generations after Newton and Huygens included brilliant minds -- a string of Bernoullis, Diderot, Euler, D'Alembert, Wolff, Du Châtelet, Maupertuis, etc. --), then other ages of philosophical decline on some dimension or another are also possible. For example, Harry Frankfurt is convinced that the age of giants is over, and we have entered an age of decline ("the field is quiet. We seem, more or less, to be marking time.")
By contrast (to Frankfurt), regular readers of my musings know that I broke with my own (lazy naturalist) education in the philosophy of science, and have come to think that until David Lewis reintroduced quite modest [modest because largely modular] systematic considerations, much twentieth century analytical philosophy is a philosophical waste-land despite the brilliant distinctions and the non-trivial conceptual (and formal) innovations of the period (which turned out to be fertile for other sciences); the reputations of many third and fourth generation analytical philosophers are overblown, despite often endless praise ("eminent," "distinguished," "brilliant," etc.), their work exhibiting lack of durability and systematic robustness (recall).
In a puzzle-solving, abductive regime, results are -- at regular pace with lots of hard labor -- cheap. (Of course, they can generate quite a number of success goods to the puzzler who gets there first or most elegantly; or has enough students to keep citing him, etc.) But in such a regime the concepts are not really stress-tested until they are taken up in empirical or technological sciences (as happened with formal semantics, computing theory, game theory, and a wide variety of philosophical concepts in psychology and linguistics etc.). That is to say, and to reiterate, puzzle-solving regimes can be extremely fertile for the special sciences; that's compatible with decline in other respects, especially absent systematic, durable background theory. Lewis re-opened the search for that elusive prey. (Sadly, many Lewisians are far narrower in range than he was.) Stein reminds us that this search must be tempered with ongoing sensitivity to how scientifically stress-tested-concepts (see this paper by Stone) bear on experience.