The quote highlights a fundamental aspect of scientific progress often overlooked: the evolution of what we deem observable facts. During revolutions in science, it's not merely the theories or models that shift but also the very foundation of observation and evidence that underpin scientific knowledge. This resonates with the concept that scientific paradigms influence perceptions; what scientists observe is shaped by prevailing theories, tools, and conceptual frameworks. When these paradigms shift—as in the Copernican Revolution or the overthrow of Newtonian mechanics—the criteria for what constitutes an observable fact often transform accordingly. This phenomenon underscores a critical epistemological insight: scientific facts are, to some extent, theory-laden. The tools scientists develop and the language they employ influence what findings are considered valid observations. This process challenges the notion of objective, unchangeable facts, suggesting instead that facts are contextual and dynamic within scientific paradigms. Recognizing this fluidity is essential for appreciating how scientific knowledge evolves and for understanding the limitations and scope of empirical evidence. It also prompts us to consider scientific realism and anti-realism debates—whether scientific theories reveal true descriptions of the world or are merely useful instruments. In summary, the quote invites discussion about the interconnectedness of theory and observation in science and calls for a more nuanced understanding of epistemology, emphasizing that scientific revolutions redefine the very universe of facts we consider observable, thereby reshaping our understanding of reality itself.