I remember reading some Feynman lecture in which he specifically mentions how bad this is... anyone got a citation for me?
Perhaps you are referring to this passage of "Cargo Cult Science":
"There is also a more subtle problem. When you have put a lot of ideas together to make an elaborate theory, you want to make sure, when explaining what it fits, that those things it fits are not just the things that gave you the idea for the theory; but that the finished theory makes something else come out right, in addition."
Perhaps you are referring to this passage of "Cargo Cult Science":
"There is also a more subtle problem. When you have put a lot of ideas together to make an elaborate theory, you want to make sure, when explaining what it fits, that those things it fits are not just the things that gave you the idea for the theory; but that the finished theory makes something else come out right, in addition."
http://calteches.library.caltech.edu/51/02/CargoCult.pdf
(Caltech lecture series is primary source)
http://www.lhup.edu/~DSIMANEK/cargocul.htm
(There are several online reprints of this lecture text in HTML, more searchable than .PDF format.)
See
http://en.wikipedia.org/wiki/Cargo_cult_science
for background and both of those citations.