The thesis of theory-ladenness is most strongly associated with the late 1950s and early 1960s work of Norwood Russell Hanson, Thomas Kuhn, and Paul Feyerabend, and was probably first put forth (at least implicitly) by Pierre Duhem about 50 years earlier.
Theory-ladenness poses a problem for the confirmation of scientific theories since the observational evidence may already implicitly presuppose the thesis it is supposed to justify.
This effect can present a challenge for reaching scientific consensus if the disagreeing parties make different observations due to their different theoretical backgrounds.
However, Kuhn was a moderate relativist [citation needed] and maintained the Kantian view that although reality is not directly knowable, it manifests itself "resisting" to our interpretations.
On the contrary, Feyerabend completely reversed the relationship between observations and theories, introducing an "extra-strong" form of theory-ladenness in which "anything goes".
But in many cases this does not pose serious practical problems as long as the presumed theses are either correct or only contain mistakes irrelevant to the intended application.