"Freedom and Necessity in the Sciences," a lecture by J. Robert Oppenheimer

Listen to the Lecture

Quick Reference

• 0:20-2:30: Introduction
• 2:30-5:36: New challenges in this modern age
• 5:36-19:20: Exponential nature of science; our culture's neglect of science
• 19:20-26:12: Evaluation of scientific discovery by necessity and by freedom
• 26:12-26:58: Definition of necessity
• 26:58-33:39: First Theme: Symmetry and Chance
• 33:40-43:59: Second Theme: Motivations for Growth of the Sciences
• 44:00-55:40: Third Theme: Theory as Invention, Discovery, and Revision
• 55:40-59:59: Fourth Theme: Chance as Limitation and Selection
• 1:00:00-1:09:20: Fifth Theme: The Choice Inherent to Learning
• 1:09:20-1:19:46: Conclusion: To be accessible to the public, scientific discovery must be judged both by necessity and by freedom, appealing both to practicality and to the desires of the human spirit.

Detailed Summary

• 0:20-2:30: Oppenheimer is introduced.
• 2:30-5:36: He opens by declaring that we live in a society with "peculiarities," with different challenges than those before us have faced.
• 5:36-19:20: Oppenheimer speaks on the nature of science and its place in our culture. He states that because of the increased speed of scientific (and other modes of) development, the things that mean the most to our culture are no longer what we have in common. The latest advances of science are not accessible to the public, and this has a negative impact on our society. Science builds from itself at an exponential rate, and thus true understanding of a scientific discovery is difficult to obtain. The nature of being alive gives us a certain unity; but that unity does not teach us what we need to know about life or science.
• 19:20-26:12: When we evaluate either human affairs or scientific discoveries, Oppenheimer maintains, there are two modes of assessing them: evaluating by the use and practicality of a thing (necessity), or evaluating by the moral or intellectual quality of a thing (goodness, freedom). Those things that are necessary cannot be praised nor condemned; but those things that are good are and must be praised and cultivated. Oppenheimer uses five stories of science to elucidate the nature of this contrast and relationship between freedom and necessity.
• 26:12-26:58: He defines necessity as something which follows logically from a general principle. Necessity is not opposed to good or freedom, it is "simply the opposite of the accidental... and of the inherently unintelligible." He tells his audience that it is a never-finished task to remove the chance that opposes necessity and symmetry.
• 26:58-33:39: This opens the discussion of his first theme, symmetry and chance. Oppenheimer explains that, in complex systems, the time needed to obtain symmetry is longer than a lifetime; some things seem out of kilter but in reality are part of the larger order, or necessity. Of necessity, we operate in a symmetrical system; when we do not have the resources or time to figure out how a certain action fits into that symmetry, we call that chance.
• 33:40-43:59: Oppenheimer then examines his second theme, the development of science and motivations for the sciences' growth. He states that there are two catalysts: the pursuit of knowledge for knowledge's sake (freedom), or the fact that someone wants something (necessity). He emphasizes that either of these can result in scientific discovery and that they are not always separate motives but rather interact and intertwine. However, he is careful to note that neither motivation can be conflated with nor reduced to the other, but that both motives have their place.
• 44:00-55:40: The concept of science as both for pure thought and for practicality leads Oppenheimer to his third theme, the theory as invention, discovery, and revision. He speaks of the theory as something that starts with an idea or thought and tries to make sense of and adjust the "big picture." However, he states that with the revision of that picture, or the "old necessity," the picture changes: the old necessity must yield to a new system. The progression from old necessity to new necessity yields new information, but also makes invalid all the information given by the old system. He speaks of ideas as inventions instead of discoveries: that the idea of charge, for example, was an invention, but that the thing itself remains vivid and rooted in reality.
• 55:40-59:59: Oppenheimer's fourth theme is chance as limitation and selection. He mentions the theory, originated by Laplace, that contends that if we only knew the velocity and location of every particle and the universe, we could predict the future. Oppenheimer discards this idea as he reminds his audience that, as humans, we cannot possibly solve this equation. The selection of what knowledge we discover and what knowledge we cannot is marked by chance. He emphasizes that if we had all the knowledge in the world we would not be able to comprehend it, remarking, "When you listen, the only reason you can hear is that you fail to listen to a great deal." In order to learn about or comprehend anything, we must sacrifice the concept of knowing everything, because it is impossible. Knowledge is inherently incomplete.
• 1:00:00-1:09:20: Given this incompleteness, we must make a choice as to which knowledge we will pursue: Oppenheimer's last theme is the choice inherent to learning, which he relates to the dual nature of light as wave and particle. Information about the wave cannot apply to the particle, but nor can the two be separated; once a thing is tested as a wave, it cannot be examined as a particle. One precludes the other. Finding out more about the equation renders the equation invalid, just as finding out more about an old necessity causes it to yield itself into a new necessity with more questions than answers.
• 1:09:20-1:19:46: Oppenheimer concludes by declaring that in making the choice of judgement by freedom or judgement by necessity, we must be guided by matching up one to the other, matching the ideological and theoretical terminology to the concrete facts and practicality of the situation. In order for the public to appreciate and value scientific discoveries, those discoveries must be something the public is able to understand. The discovery must deal with something intelligible and familiar; and it must appeal to the aspirations of the human spirit. If the necessity of the practical relatability of the discovery and the freedom of the knowledge-seeking quality of it are both satisfied, the public can understand the true importance of the discovery. Only then can we unite around that which is most precious and important to us as humans, our relationship to nature and the advancement of learning.

Audio materials are reproduced here with the kind assistance of the Library of Congress Manuscript Division, who hold the originals in the Motion Picture, Broadcast, and Recorded Sound Division, National Audiovisual Conservation Center, Packard Campus, Culpeper, VA.