Leibowitz and Agassi: Conversations on Philosophy of Science - Part 7

Leibowitz and Agassi: Conversations on the Philosophy of Science" is a television series of rare complexity and philosophical depth, serving as a cornerstone of twentieth-century Israeli intellectual discourse. Part VII of the series, like the collection as a whole, presents an intellectual distillation of fundamental issues at the heart of the philosophy of science—specifically the validity of scientific theories, the limits of science, and the demarcation between science and metaphysics. This discussion unfolds across the fertile tension between two iconic yet contrasting figures: Professor Yeshayahu Leibowitz, a multifaceted Renaissance man, chemist, and critical Torah scholar; and Professor Joseph Agassi, a philosopher of science and a prominent disciple of Karl Popper. The core theme of this segment concerns the validity of scientific theories and the criteria that distinguish science from non-science. Agassi, as a staunch "Popperian," presents the theory of falsification as the heart of the scientific method. According to Popper, empirical evidence can never absolutely confirm a theory, as a future observation could always emerge to contradict it. Conversely, a single observation that conflicts with a theory can refute it. A true scientific theory, therefore, must be falsifiable—meaning there must be a theoretical factual state in which it would be considered incorrect. This approach stands in firm opposition to classical inductivism, which seeks to derive general rules from a large number of observations (a problem often attributed to David Hume). It likewise contrasts with views suggesting that an accumulation of observations strengthens scientific theories—a concept Leibowitz identifies as having a distinctly human, functional dimension, even if he does not fully subscribe to it. Leibowitz brings his profound anti-metaphysical stance to the debate, arguing that science does not deal with an essential "truth" about the world as it "really" is, but rather provides useful descriptions and tools for understanding and controlling it. In his view, science is a human activity, an interpretative tool, and a conceptual framework rather than an unveiling of the layers of reality. He frequently emphasizes the sharp distinction between fact and value: science can describe reality but cannot contain values or dictate what is worthy and right. This position is well-reflected in discussions regarding "scientific revolutions" as described by Thomas Kuhn, who also emphasized the social and psychological aspects of paradigm shifts rather than just the rational-objective ones. Leibowitz tends to view the transition between theories—for instance, from Newton to Einstein—as a shift from one useful paradigm to another, rather than a closer approximation of absolute truth. The central tension emerging in this section focuses on the status of scientific theory. Is it a human instrument for our benefit, as Leibowitz suggests, or is its aspiration toward truth, even if that truth is never decisively reached, as the Popperian Agassi might argue? Agassi, with his characteristic criticality, likely focused on historical examples of refuted theories and the importance of constant scrutiny regarding the foundations of science. He emphasizes the efforts of figures like Ernst Mach or Pierre Duhem, who examined the limits of our ability to absolutely verify or refute theories and illustrated the complex interplay between theory and observation. Agassi would insist that theories must possess "empirical content"—meaning they must say something about the world that can be tested. Leibowitz, for his part, would question whether this content is truly objective or if it is dependent on human language, conceptual scales, and perhaps even cultural perspective. Key questions arising from this discussion include: Is there an absolute criterion for distinguishing between science and metaphysics? Is there a correlation between scientific "progress" and objective "truth"? What is the status of scientific laws—are they descriptions of reality or tools we create to describe and master it? And what is scientific rationality—is it an objective concept or an interpretative tool? Agassi, inspired by Popper, would argue for a critical rationality that encourages refutation and critique. Leibowitz, by contrast, might view this rationality as a human activity that also has its limits, carrying with it the conscious recognition that we have no direct access to absolute "truth." The significance of the entire series, and particularly segments such as Part VII, is immense as an Israeli cultural and educational document. it exposed a broad Israeli audience—much of which had not been exposed to the philosophy of science in such depth—to intellectual debate of the highest order. Through the tension between Leibowitz and Agassi, fundamental philosophical problems and existential questions regarding knowledge, truth, and the status of man in the universe were presented to the public. The series represented the pinnacle of public discourse in Israel, proving that there is a demand for deep philosophical-scientific discussions even in a television format. It taught the public critical thinking, raised doubts, and challenged authorities, functioning as a sort of open yet demanding house of study at the heart of Israeli society. The brilliant and challenging dialogue between these two spiritual giants, referencing key thinkers in the history of scientific and philosophical thought, remains a milestone in the identification and shaping of Israeli intellectual identity.

Video transcript