Kuhn-1962-structure-of-scientific-revolutions rejects the idea that we observe the world then create theories to explain what we observed; the view held by both popper-1934-logic-of-scientific-discovery and logical-empiricism.
Instead, what we observe and how we describe it is shaped by our theoretical frameworks (paradigm). Because paradigms determine what counts as a fact, a problem, or an anomaly, scientists working in different paradigms may have different observations to the “same” thing.
If observations were neutral, then contradictory evidence would instantly refute a theory. Instead, in practice, anomalies are often reinterpreted or may not even be seen as anomalies at first, because scientists interpret data through the existing framework. The theory-ladenness of observation also supports incommensurability as different paradigms may disagree about what is being observed in the first place.
“But is sensory experience fixed and neutral? Are theories simply man-made interpretations of given data? The epistemological viewpoint that has most often guided Western philosophy for three centuries dictates an immediate and unequivocal Yes! In the absence of a developed alternative, I find it impossible to relinquish entirely that viewpoint. Yet it no longer functions effectively, and the attempts to make it do so through the introduction of a neutral language of observations now seem to me hopeless.” Kuhn, p. 126
Kuhn-1962-structure-of-scientific-revolutions is not confidently rejecting empiricism but he does say that the traditional model doesn’t function effectively anymore. He still believes sensory experience matters, but what counts as observation statements, what is noticed, how instruments are read, what is relevant, all depend on the paradigm.
Example for the paradigm-shift-from-phlogiston-to-oxygen, saying that “i see oxygen being produced” presupposes the existence of oxygen which is not available to the phlogiston paradigm. Hence this isn’t a neutral observation, as it is observation that could only be made by the oxygen paradigm.