Filtered HSS Courses (2026-27)

It took less than seven years from the discovery of nuclear fission in 1938 to the ignition of the first atomic bomb in the summer of 1945 and its subsequent use against the cities of Hiroshima and Nagasaki. In this course, we will take a deep dive into this development, which forever changed the dynamics of global politics — as well as our views on science. In addition to the Manhattan project, the course will also cover the nuclear weapon programs in other countries, in particular Nazi Germany. We will place the rapid development of the war years in a wider historical context, from the first anticipations of atomic weapons to the rise of “big science” in the postwar years. In this way, we will be able to address the pressing ethical questions (and their continuing relevance to scientists today) in a nuanced, historically informed way.

Students attend four lectures, featuring speakers from outside Caltech, on topics in the history and philosophy of science. Students may choose from a variety of regularly scheduled HPS lectures, including HPS seminars, Harris lectures, and History seminars (history or philosophy of science only). Graded on attendance. Not available for credit toward the humanities-social science requirement. Graded pass/fail.

An individual program of directed reading in history and philosophy of science, in areas not covered by regular courses.

Offered in any two consecutive terms, by arrangement with HPS faculty. Under the guidance of an HPS faculty member, students will research and write a focused research paper of 15,000 words (approximately 50 pages). Work in the first term will comprise intensive reading in the relevant literature and/or archival or other primary source research. In the second term, students will draft and revise their paper. Open to seniors in the HPS option and to others by special permission of an HPS faculty member.

Students attend four lectures, featuring speakers from outside Caltech, on topics in the history and philosophy of science. Students may choose from a variety of regularly scheduled HPS lectures, including HPS seminars, Harris lectures, and Munro seminars (history or philosophy of science only). Graded on attendance. Not available for credit toward the humanities-social science requirement. Graded pass/fail.

Correlation may not imply causation, but what does imply causation? This course covers accounts of causation and offers an introduction to the causal graphical modeling framework. The course will consist of a mixture of philosophical analysis and the introduction of statistical and algorithmic techniques to infer causal relations from data.

An introduction to fundamental philosophical problems concerning the nature of science. Topics may include the character of scientific explanation, criteria for the conformation and falsification of scientific theories, the relationship between theory and observation, philosophical accounts of the concept of "law of nature," causation, chance, realism about unobservable entities, the objectivity of science, and issues having to do with the ways in which scientific knowledge changes over time.

This course will focus on questions about the nature of space and time, particularly as they arise in connection with physical theory. Topics may include the nature and existence of space, time, and motion; the relationship between geometry and physical space (or space-time); entropy and the direction of time; the nature of simultaneity; and the possibility of time travel.

This course will focus on philosophical and foundational questions raised by quantum physics. Questions may include: Is quantum mechanics a local theory? Is the theory deterministic or indeterministic? What is the role of measurement and observation? Does the wave function always obey the Schrödinger equation? Does the wave function give a complete description of the state of a system? Are there parallel universes? How are we to understand quantum probabilities?

Humans are in the midst of the sixth mass extinction-the first to be caused by human activity. Extinction has been viewed in changing ways over the past 200 years, and this course takes an interdisciplinary approach to learning about the extinction process from a historical as well as a modern perspective. Our focus will be on the extinction of biological entities, but we will also touch on other systems that have disappeared: languages, technologies, habitats, and ways of living. Central to our endeavors will be asking what it means to live in this time of loss: Should we mourn? And if so, how do we mourn for what many or most of us do not see, but only read about? Finally, we will scrutinize what the practical effects of extinction have been, are, and will be. We will also make at least one visit to a natural history museum to view some extinct species behind the scenes.

Humans' conceptions of nature have changed dramatically over time. Ecological systems influence human culture, politics, law, and many other spheres, and in turn, humans influence those systems. This class introduces students to the field of humanistic ecology-a discipline that looks to a number of cultural, political, historical and economic elements to better understand the role of ecology in a larger sphere outside of its scientific structure and uses. Humanistic ecology is designed to provide context for the study of ecology, and in a fundamental way, focuses on the appropriate role of humanity in its relationship to nature: what is ethical, or not, what is useful, or not, and a variety of other matters that should be considered when taking a fully three-dimensional view of ecological science.

The oceans constitute more than 70% of the planet, and have their own complications and fascinations. With each passing decade, they also become more important to our well-being. Although fully half of the world’s peoples now live within a hundred miles of an ocean, few today have a working knowledge of the sea. Yet scientists, historians, artists, and others have assembled an astonishing series of stories that cross centuries and push up to the present day. This science-forward humanities course tells some of these stories, offering up a thorough overview of how our relationships with the oceans have evolved, what elements of society are affected by its many facets, and why its cultural aspects are vital to our futures. We will also have a field trip to the Huntington to view related materials in the archives.

The United States made an astonishing transition from scientific backwater to superpower over the course of just one century, culminating in the atomic bomb. This course will track the development of peculiarly American conceptions of scientific methodology in the context of this rapid transition. American conceptions of science tend to privilege the practical over the theoretical. We will focus on two such conceptions: operationalism and behaviorism. Operationalism was developed to reconcile a practical conception of physics with radical theoretical changes due to relativity and quantum mechanics. Behaviorism extended this account of the theory and practice to the domain of psychology. Special attention will be given to class discussion and reading primary texts: Major figures include Peirce, Bridgman, Boring, Stevens, and Skinner.

The development of quantum mechanics in the years 1900-1927 was one of the greatest conceptual transformations in the history of modern science. In this course, we still study this development, from Max Planck's first papers on black body radiation to the debates between Albert Einstein and Niels Bohr at the 1927 Solvay conference. The course will take a holistic view of this development, covering experimental breakthroughs, the development of mathematical formalism and physical concepts, as well as the broader philosophical and historical context of early 20th century Europe. Students will acquire an understanding of a scientific revolution that goes beyond well-worn stories of sudden heroic epiphanies.

This is an advanced humanities course on a specialized topic in HPS and Philosophy. It is usually taught by new or visiting faculty. The course may be re-taken for credit except as noted in the course announcement. Limited to 15 students. See registrar's announcement for details.

This is an advanced humanities course on a specialized topic in HPS and History. It is usually taught by new or visiting faculty. The course may be re-taken for credit except as noted in the course announcement. Limited to 15 students. See registrar's announcement for details.

In Plato's Phaedrus, Socrates famously described the virtues of two ways of looking at the world. The first entailed "seeing together things that are scattered about everywhere and collecting them into one kind," while the second was the skill "to cut up each kind according to its species along its natural joints, and to try not to splinter any part, as a bad butcher might do." In a similar sentiment, Darwin wrote in 1857, "It is good to have hair-splitters and lumpers." How have scientists and laypeople perceived similarities and differences in the living world? How have they divided nature into distinct kinds and individuals? How have they distinguished between parts and wholes? Where have they positioned human beings within nature's order? What were the consequences of finding different kinds of order in nature? This course explores these and related questions historically. We will consider different approaches to making sense of nature, and how a multitude of perspectives have been brought to bear on this ordering project. Topics covered include taxonomy and classification, race science and scientific racism, gender and sex differences, disease categories and immune selfhood, and symbioses and biogeochemical cycles.

This course explores late medieval European understandings of the origins, structure, and workings of the cosmos in the realms of theology, physics, astronomy, astrology, magic, and medicine. Attention is given to the position of humans as cultural creatures at the intersection of nature and spirit; as well as to the place of Christian Europeans in relation to non-Christians and other categories of outsiders within and beyond Europe. We will examine the knowledge system that anticipated racializing theories in the West.