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Common Knowledge 24:1

DOI 10.1215/0961754X-4253769

exploded shortly after liftoff, killing all seven crew. A presidential commission

was formed to investigate the accident. Most of the commissioners were associ- ated with the space program and dutifully followed their chair, former Secretary

of State William Rogers. The exception was physicist Richard P. Feynman,

who was off on his own, talking to the engineers. At NASA they told him that

Challenger’s O- rings showed scorching. These O- rings were gaskets more than

ten meters long, sealing the seams between booster sections against escaping gas.

Scorching suggested they failed. He learned that engineers had been worried

about the O- rings for some time but that their concerns were disregarded. This was not the first or even an early shuttle launch. There had been many,

and by 1986 they were almost routine. So why should O- rings fail on January 28

and never on previous launches? Feynman also learned that the contractor had

been testing O- rings under conditions of cold, indicating concern. The 1986

launch was the first to occur when the temperature was below freezing. None of

this information — scorching, contractor’s concern, different weather — was in the

evidence before the commission. The New York Times heard what Feynman was hearing and published a

story suggesting problems with cold O- rings. Caught off guard, the commission

chair called a public meeting to review the Times’s evidence in the presence of

reporters and television cameras. At dinner the night before, Feynman got the

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1. General Donald Kutyna, as cited in Gribbin and Grib- bin, Richard Feynman, 236 – 37. 2. From the Rogers Commission press conference. 3. Feynman, Pleasure of Finding Things Out, 240. idea of taking a sample of the O- ring, clamping it tightly, and dunking it in ice

water. Would it spring back to form? The next day, before the meeting, he went to

a hardware store to purchase tools and a C- clamp, then privately tried the experi- ment with the head of NASA in his office. The cold material remained deformed. Feynman took his place when the meeting came to order, dripping pliers

and C- clamp in his pocket. A NASA manager began explaining O- rings, passing

a sample to the commissioners. It was when the sample got to him that Feynman

performed his cool experiment. Another commission member recalls: He laid it [the sample] in front of him, reached into his pocket, and got

out a pair of pliers, a screwdriver, and a clamp. I thought, “Oh my God,

what’s he going to do?” He proceeded to take this thing apart. He was

going to take a piece of this O ring rubber, put his clamp on it to com- press it, like it got compressed in the shuttle joint, then put it in ice water

to cool it down to the temperature on the day of the launch, and show

that the O ring did not bounce back to its original form.1 As he was preparing the material, Feynman spoke to the NASA manager who

had been testifying: I took this stuff that I got out of your seal, and I put it in ice water,

and I discovered that when you put some pressure on it for a while and

then undo it, it maintains — it doesn’t stretch back. It stays the same

dimension. In other words, for a few seconds at least — and more seconds

than that — there’s no resilience in this particular material when it is at a

temperature of thirty two degrees. I believe that has some significance

for our problem.2 That evening, all the major television networks showed Feynman’s experiment.

The next day, it was the front page story in the New York Times and the Washing- ton Post. It was a test anyone could have done but no one did. Feynman became a

national hero and public figure. Some years before, Feynman had been asked to explain what science is, and

he replied: “The separation of the true from the false by experiment or experi- ence, that principle and the resultant body of knowledge which is consistent with

that principle, that is science.”3 He reiterated this elegant creed at the conclusion

of lectures that he gave on the concept of physical law: If it disagrees with experiment it is wrong. In that simple statement is

the key to science. It does not make any difference how beautiful your

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3 4. Feynman, Character of Physical Law, 156. 5. See Duhem, Aim and Structure of Physical Theory;

Quine, “Two Dogmas of Empiricism”; and Kuhn, Struc- ture of Scientific Revolutions. 6. Robert Boyle, as cited in Sargent, “Learning from

Experience,” 68. 7. Sargent, Diffident Naturalist, 198, 201 – 2. guess is. It does not make any difference how smart you are, who made

the guess, or what his name is — if it disagrees with experiment it is

wrong. That is all there is to it.4 Yes, of course, one might say. The trouble comes when we have to determine

whether a conjecture disagrees with experiment. Is it really that obvious? We

have to decide that the experiment was done correctly. Responsibility for the

decision cannot be foisted on impersonal logic. No observation can be stated

without using a language, and there is never one uniquely scientific, empirically

respectable way to do so. What experiments show is always to some degree a

decision, the discretion that logic leaves to experience. It is impossible to separate

what the experiment shows from the experience of those with the authority to

say what it means.5 Is what Feynman did an experiment at all? What did he demonstrate? Was

it that a failure in cold O- rings caused the Challenger explosion? That conclusion

would require some additional assumptions worth exploring. It was not raining

on the morning of the launch. The seals were cold but not soaking wet, as Feyn- man’s sample was. The metal of his clamp was probably not the same alloy as the

boosters; how do we know that these things do not matter? The pressure in Feyn- man’s hand- tightened clamp was uncontrolled. It seems likely that the seals were

subject to much greater pressure due to the massive weight of the booster rockets

they joined. How do we know that it makes no difference? And what about time?

The Challenger seals were exposed to the cold for hours, Feynman’s sample for

a few seconds. It may seem obvious that more time would only amplify the effect

that Feynman demonstrated, but obvious things can turn out to be wrong. Feynman tested a minuscule sample of the sealant. How do we know that

a bigger piece responds in the same way? Robert Boyle, the seventeenth- century

prince of experiments, observed that “divers experiments succeed, when tried

in small quantities of matter, which hold not in the great.”6 In his Experimental

History of Cold (1665), Boyle recounts his investigation of reports that iron hoops

surrounding water barrels break in very cold weather. Boyle wondered at the

cause. Did cold change the iron, or was there some other agent? The expansion

of water on freezing was not then a fact and was even contradicted. The first thing

that Boyle had to do was confirm that freezing water expands. Then he went on

to show that it was this expansion and not some direct action of cold on metal

that broke the hoops.7 Feynman might dismiss such quibbles, but he also might agree that quibbles

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8. Feynman, Character of Physical Law, 156 – 57. 9. Freeman Dyson, as cited in Gribbin and Gribbin, Rich- ard Feynman, 238. have a point. He believes in experiments, but he wants his experiments carefully

checked. He was notorious for checking students’ calculations, and he found mis- takes often enough to appreciate that little things need to be scrutinized. As he

says, an experiment has to be rubbed back and forth: When I say if [a hypothesis] disagrees with experiment it is wrong, I

mean after the experiment has been checked, the calculations have been

checked, and the thing has been rubbed back and forth a few times to

make sure the consequences are logical consequences from the guess

[the conjecture being tested], and that in fact it disagrees with a very

carefully checked experiment.8 Having done his experiment privately, Feynman could have informed the

commission chair. He could have recommended that engineers do a full test. He

chose instead to give his performance. I like to think that he wanted others to

have the experience that he did when he performed the test privately. The value of

an experiment is in its power to alter the trajectory of inquiry, but to exercise that

power an experiment must be experienced by those who stand to learn from it. There are two ways to look at experiments, as probative proofs or as instru- ments of invention. Philosophers have a tendency to emphasize the probative

value of experiments. Experiments prove, demonstrate, justify, confirm, sup- port, verify. A minor tradition in empirical philosophy holds that the value of

experiment is that of an instrument. If used well, experiments can greatly advance

empirical knowledge, not by what they prove but by how they change questions

in a productive way. Freeman Dyson, Feynman’s colleague and friend, interprets Feynman’s

experiment in this first way. He thinks that the Challenger Inquiry demonstra- tion was Feynman’s finest hour. Feynman gave the public truth, made truth pres- ent before them with his hands: “The public saw with their own eyes how science

is done, how a great scientist thinks with his hands, how nature gives a clear

answer when a scientist asks her a clear question.”9 Is that what Feynman did,

pose a clear question to nature and receive a clear answer? Dyson does not say to

what truth he refers. That cold O- rings caused the Challenger explosion? Surely

not. If that was his hypothesis, the quibbles I have presented become suddenly

serious, and Feynman’s experiment looks rushed and shabby. What Feynman called “our problem,” addressing the commissioners, was

why the Challenger exploded. In that form, the question is imponderable. Why

does anything happen? But introduce a new question — Did cold O- rings con- tribute to the explosion? — and you have something to explore. Feynman took a

nebulous question with no answer in sight and enforced a detour. If you want to

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5 10. See Proclus, Commentary on the First Book of Euclid’s

Elements. 11. “Whatever evidence there is for science is sensory evi- dence.” Quine, Ontological Relativity, 75.

pursue that big question now, you have to pass through some little questions that

he succeeded in imposing along the way. What do we know about the effect of

cold on O- rings? How cold? How long? What other components may have been

affected by the temperature, or by the failing O- rings? Questions that had not

seemed important the day before were now the order of the day. His experiment

did not answer a question; it tendered one. The two ways of looking at experiments correspond to a duality in Western

empiricism that I suggest be described in Euclidean terms.10 Euclid distinguished

theorematic from problematic sciences. Theorems demonstrate the reality of

something that exists independently of our knowledge. A theorem is grasped by

theorein (in Latin, contemplatio), disinterested scientific thinking; it is a theorem,

for example, that the sum of a triangle’s internal angles is the same as two right

angles. Such theorems invent or construct nothing. They disclose the timeless

relations of eternal forms. All that is new is our knowledge of them. Problems,

on the other hand, require the construction of a solution that did not previously

exist. In Euclid’s geometry, the sought- for solution arises from a series of opera- tions that construct a figure: given a straight line, describe a square; inscribe an

equilateral triangle in a circle; and so on. Empiricisms also tend to one or the other, the theorematic or the problem- atic, in how they understand the relation between experience and knowledge. Is

experience expected to justify an assertion or to make a theorem evident? If so,

then one is dealing with a theorematic empiricism. The value of experience is

the evidence it confers on a hypothesis. Experience duly methodical is the royal

way to truth in science. When, alternatively, experience is expected to contribute

to the explanation of a problem, one is dealing with a problematic empiricism

that produces both questions and answers. Problematic experience has inven- tive potential, and, when understood problematically, the value of experience lies

in what it invents. Theorematic empiricism values experience for the evidence

it contributes to theory and to theorematic truth. “Experience is ultimate evi- dence” is the slogan of theorematic empiricism.11 Problematic empiricism values

experience for the problems it discovers, the solutions it invents, the techniques

it bequeaths, and the sensitivity that its culture cultivates to problems not yet

well defined. Ancient empiricism was split. Greek medical empiricism was problematic,

as was the empirical philosophy of Epicurus, while Aristotle’s empiricism favored

contemplative values. Problematic empiricism was strong in the seventeenth cen- tury; for instance in the work of Francis Bacon, Galileo, and Boyle. A theorematic

trend predominates in the eighteenth and nineteenth centuries, while radical

empiricisms of the twentieth century reclaim experience for problematic thought,

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12. Sellars, Empiricism, Davidson, Subjective, and Rorty,

“Higher Nominalism in a Nutshell,” 462 – 66. 13. Dewey, Experience and Nature, 283 – 84. 14. For “Red here now,” see Carnap, “Die physikalische

Sprache” and “Über Protokollsätze.” restoring its instrumental value. William James and John Dewey are practitioners

of problematic empiricism (which James named “radical empiricism”), along with

Henri Bergson and Gilles Deleuze. Prominent nominalists in Analytic philosophy, including Wilfrid Sellars,

Donald Davidson, and Richard Rorty, attack empiricism with the argument that

only a belief can be a reason for a belief. Only a proposition can justify a proposi- tion. There is nothing for “experience” to do until it is described with a proposi- tion, and then it is the proposition that matters, not the experience, which is at

most a cause and not a reason.12 Part of this argument is indisputable: only a belief

can be a reason for a belief. But no one would say that only a belief can create a

belief, or only a proposition inspire a proposition. The only thing that can cre- ate a new belief or proposition is experience. If we feel dissatisfied by concepts,

motivated to seek new and different ones, it is not because of logic, which accom- modates anything (with compensatory adjustment). Dissatisfaction with concepts

comes from experience. Experience has something better to do than rationalize beliefs. It can move

the creation of new ones and motivate new action to test the invention. This

experience is not a tingle or an immediate simple sensation. What is really given

in and as experience is the feeling of a problem. Dewey nicely describes the given

as a condition of hurt and puzzlement: “The immediately given is always the

dubious . . . it is a cry for something not given.”13 It is this feeling, the feeling of

a problem and not the incorrigible protocol “Red here now,” that is the empirical

birth of knowledge.14 References Carnap, Rudolf. “Die physikalische Sprache als Universalsprache der Wissenschaft.”

Erkenntnis 2 (1932): 432 – 65. ——— . “Über Protokollsätze.” Erkenntnis 3 (1932): 215 – 28. Davidson, Donald. Subjective, Intersubjective, Objective. Oxford: Clarendon, 2001. Dewey, John. Experience and Nature, 2nd ed. La Salle, IL: Open Court, 1929. Duhem, Pierre. The Aim and Structure of Physical Theory. Translated by Philip P.

Weiner. 1906; Reprint Princeton, NJ: Princeton University Press, 1954. Feynman, Richard P. The Character of Physical Law. Cambridge, MA: MIT Press,

1967. ——— . The Pleasure of Finding Things Out, edited by Jeffrey Robbins. New York:

Basic Books, 1999. Gribbin, John, and Mary Gribbin. Richard Feynman: A Life in Science. New York:

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7Kuhn, Thomas S. The Structure of Scientific Revolutions, 2nd ed. Chicago: University

of Chicago Press, 1970. Proclus, Commentary on the First Book of Euclid’s Elements. Translated by Glenn R.

Morrow. Princeton, NJ: Princeton University Press, 1992. Quine, W. V. “Two Dogmas of Empiricism.” In From a Logical Point of View, 2nd ed.

New York: Harper and Row, 1961. ——— . Ontological Relativity and Other Essays. New York: Columbia University Press,

1969. Rogers Commission press conference, www.youtube.com/watch?v=ZOzoLdfWyKw

(accessed April 30, 2015). Rorty, Richard. “The Higher Nominalism in a Nutshell.” Critical Inquiry 12, no. 2

(1986): 462 – 66. Sargent, Rose- Mary. “Learning from Experience: Boyle’s Construction of an

Experimental Philosophy.” In Robert Boyle Reconsidered, edited by Michael Hunter,

57 – 78. Cambridge: Cambridge University Press, 1994. ——— . The Diffident Naturalist: Robert Boyle and the Philosophy of Experiment. Chicago:

University of Chicago Press, 1995. Sellars, Wilfrid. Empiricism and the Philosophy of Mind. Cambridge, MA: Harvard

University Press, 1997.

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