I just wanted to second Mathew Forstater's comments in reply to Brad DeLong.
Mathew Sunday Aug. 9,98: "that dreams, chance, accidents, hunches, intuition, gut feelings, imagination, creativity, etc have all played an important part in hypothesis formulation and scientific discovery is well documented. it may not make it into the final versions of the journal articles, but it is there in scientists' personal journals, in diaries, memoirs, interviews, etc. people who have emphasized this, like the mathematician Georges Polya and the physical chemist Michael Polanyi also argue that awareness of the contribution of these facteors actually increases their power. (C. Wright Mills on the sociological imagination, C.S. Peirce and Norwood Hanson on retroduction and abduction are also useful here. also Einstein on the free creation of the mind. [i have a paper that argues this is also relevant for constructing an alternatative approach to 'rational' or 'optimal' planning]).
by the way, economists are generally much worse on all this than physicists and mathematicians; economists' "physics envy" (mirowski) and their insecurity about the 'scientific' soundness of their discipline leads to greater defensiveness on these matters, and a great reluctance to acknowledge the value of stuff that sounds too 'mushy.'"
Nicely thought out reply to Brad DeLong's comments on Althusser. Thanks. regards, Doyle Saylor