Parallels between Thomas S. Kuhn and Alfred N. Whitehead have been noticed several times. For example, shortly after the publication of The Structure of Scientific Revolutions (1962), the scientist C. H. Waddington told Kuhn that the absence of references to Whitehead in that book was disappointing, because, both epistemologically and metaphysically, it plainly addressed some of Whitehead’s philosophical themes. On that occasion Kuhn admitted that, although the parallelism was there indeed, the last time he remembered having read Whitehead was before he had formulated his current views. By that time, Kuhn added, he was not attracted by the notion of “prehension”—the one which Waddington thought embraced Kuhn’s stance as a whole. Kuhn acknowledged that Waddington’s point was an interesting one, and that he would probably give Whitehead further consideration some day—but he never actually did.
Kuhn occasionally quoted Whitehead’s brilliant sentences to support his own points. However, he used to quote William James and others in a similar manner—that is by way of a rhetorical appeal to a recognized authority—even though his own views were not necessarily in full agreement with theirs (Kuhn 1962, 113). To what extent did Kuhn know Whitehead’s philosophy? And, to what extent did he find it interesting? My aim in this paper is to answer these questions. To do so, I will show how Kuhn started from a typically Whiteheadian perspective when making his early criticisms of the empirical tradition (as represented by Bertrand Russell). I will explore Kuhn’s readings of Whitehead’s books, his use of Whitehead’s terminology, and, finally, his understanding of physical science as a process.
1. Kuhn’s Winding Route to Whitehead
Kuhn entered Harvard intending to become a theoretical physicist, but the routine of war-time physical research and his experience of graduate-level physics convinced him that he actually did not want to make a career in the field. During his undergraduate years, he found the philosophy of science to be a reasonably satisfying substitute, and so he soon hoped to become a professional philosopher instead. By mid-1943, having recently graduated with a degree in physics (summa cum laude), he told his aunt Emma Fisher that the prospect of becoming an academic philosopher, difficult as it seemed, was not out of the question. By the end of the war, Kuhn had already decided that physics would not be his future profession.
If Kuhn had planned to devote his time to philosophy when he entered Harvard in 1940, he would have done it at the right time. Quine referred to the year 1940-41 as “halcyon days” (1998, 19). Together with C. I. Lewis, H. M. Sheffer, Quine himself, and the rest of the faculty, some outstanding figures of modern philosophy, notably Bertrand Russell and Rudolf Carnap, had been or were giving courses and seminars on logic, semantics, and analytic philosophy as visiting professors. It was doubtless a good moment to start up as a philosopher. However, by that time, Kuhn had never thought of majoring in philosophy, and the requirements of a physics degree meant that by the time of graduation he had taken only one course in philosophy, and that as a freshman—the history of philosophy, taught by Raphael Demos. It played an important role in Kuhn’s intellectual development in the long run, because it helped him to discover Immanuel Kant, whose work greatly increased his early interest in philosophy. But this one course did not make up for the lack of a more complete training in the field, as Kuhn himself realized shortly after returning from war service, as he began to take some graduate courses in philosophy: there was a lot of philosophy left for him to learn.
But this is not to say that Kuhn knew little philosophy. Harvard’s Department of Physics was not devoid of philosophically minded scientists, such as Edwin C. Kemble and, particularly, Percy W. Bridgman, whose Logic of Modern Physics provided a large number of American physicists with an explicit methodological statement of the sort of physical theory they aimed to develop. The Logic of Modern Physics was a primer to Bridgman’s so-called “operational analysis,” a methodological doctrine according to which physical concepts were meaningful as long as a series of experimental procedures could be devised to provide quantitative measurement justifying their usage. It was an empiricist criterion of meaning (welcomed by Logical Positivists) that made the handling of physical concepts rely on pure verifiability. Kuhn first heard of operational analysis as an undergraduate student, and later on, during his war service, he read it through. Kuhn did not consider Bridgman’s Logic thoroughly convincing, because he did not agree that experimental procedures were altogether devoid of assumptions concerning, e.g., the reasonableness of quantitative agreement, or the aseptic scruples involved in experimental design and implementation. Kuhn had learned the significance of assumptions (though we should rather term them “preconditions”) for knowledge from Kant (and from David Hume as well), and he wanted to approach the field of psychological epistemology to discover how scientific generalizations were actually made.
With this project in mind, Kuhn started his war service by reading popular works on epistemology and philosophical analysis, philosophy of science, and science. His was the viewpoint of a young scientist and an amateur philosopher. So, together with a planned study of the Principia Mathematica, he read recent popular works by A. S. Eddington, R. A. Millikan, Max Born, and J. B. S. Haldane, and to these he added Bridgman’s Logic as well as Nietzsche’s Antichrist, The Varieties of Religious Experience by William James, some works by Sigmund Freud, Ludwig von Mises, Philipp Frank, Rudolf Carnap, and Bertrand Russell’s Our Knowledge of the External World. All these readings allow us to see that Kuhn was trying to enlarge his rather limited philosophical education. But, as mentioned above, Kuhn’s first serious encounter with “real” philosophy happened after his war service, during the Fall term of 1945, when he took H. M. Sheffer’s graduate course in symbolic logic, and Donald C. Williams’ course in metaphysics. After passing these courses, Kuhn decided not to move over into philosophy because of his lack of training in the field. Frustrating and painful though this experience must have been, it nevertheless contributed to Kuhn’s eventual philosophy of science, as we will discuss further below.
Kuhn’s first references to Whitehead’s philosophy appear at this time. In his term paper for D. C. Williams he mentioned The Concept of Nature, a book that (as we will see below) seems to have left a mark in Kuhn’s organization of the philosophical problems of physical theory. That was not the only work by Whitehead that Kuhn had read by now. Kuhn’s quotations from Science and the Modern World are well known today, but he also read (and commented on) Whitehead’s Axioms of Projective Geometry as well as Symbolism: Its Meaning and Effect. Unfortunately, we have no evidence as to when he read these two books, but if we take what Kuhn said to Waddington into account, we can infer that he must have read them before 1947, i.e., the year he fixed as the very beginning of his mature thought (Kuhn 1977, xi). He praised some of these books (especially Axioms and Symbolism), and found them useful in quite different senses, though all related to his various philosophical interests—notably causation and his view of science as process.
2. Kuhn on Russell and Causality
Kuhn’s first published papers—apart from those on solid-state physics, a direct outcome of his dissertation—date from 1951, and are mainly historical studies of science. Until 1959, Kuhn’s work is clearly historical, and included the history of chemistry in the seventeenth-century scientific revolution, the history of thermodynamics, and, of course, the Copernican Revolution. With the exception of The Copernican Revolution (Kuhn 1957), there are as yet no explicit references to the kinds of ideas that he would eventually explore in The Structure of Scientific Revolutions. In other words, until 1959 there is no explicit account of science from a philosophical (or rather, perhaps, a “metahistorical”) point of view. So we will not find any mention of the philosophical questions which mostly interested him at the outset in those publications. To study those questions we must turn to his unpublished papers. And there we find how Whitehead’s exposition of the philosophical principles of scientific knowledge influenced him.
To understand that influence it is advisable to begin by describing an early philosophical view of Kuhn in which Whitehead’s shadow is still not visible. It corresponds to Kuhn’s undergraduate studies at Harvard (1940-43). By that time, Kuhn’s philosophical image of science included some ingredients seemingly close to the empirical tradition in philosophy. I say “seemingly” because he does not follow any philosophical current at all. Kuhn shows his viewpoint in a 1941 term paper whose title was “The Metaphysical Possibilities of Physics.” In that essay, Kuhn holds an instrumentalist idea of scientific concepts together with an empirical conception of the ultimate origin andjustification of scientific theories in raw data. His perspective regarding the relation of scientific theories to absolute truth was that of a fallibilist and sceptic. The thinker who better represents his image of the nature of scientific knowledge was Hume rather than Kant. Thus Kuhn writes:
Do the fictions of physics approach nearer and nearer to the truth, and will the ultimate fiction thus correspond to the truth? […] This has been the dilemma of the physicist: he searches for a truth which, though found, cannot be proved. We can only be glad that he has not been so discouraged by it as to give up the attempt, for further investigations shows possibilities of a less discouraging nature (1941, 6).
His paper evaluates these possibilities, and his conclusions help us to see that Kuhn is rather a pessimistic scientific realist. That is, he does not take skepticism to the extreme. He finds it difficult to affirm that science articulates absolute truths about nature, but this is not in itself an impossible task. His essay is a sketch of a philosophical program leading to the removal of uncertainty.
For Kuhn physical science is a metaphysically meaningful enterprise that might give very good results (1941, 1), and philosophers would do better if they studied it properly. To that effect, the philosophical study of physics does not consist of the mere study of the a priori, such as Kant argued (1941, 3-4). Scientific assumptions are more than the mere application of permanent categories of the mind. Concepts of physics, Kuhn says, “are not the concepts of Kant’s Critique of Pure Reason” (1941, 3). Incidentally, this position links Kuhn with a naturalistic current of thought to which Whitehead is not alien.
I must re-emphasize that this small piece of work is still not the outcome of a thorough study of philosophy. Kuhn copes with the specific relation of theory to data very intuitively. He says that data are the elementary pieces of scientific theories and concepts their glue. Concepts are the way we express the loose unity we grasp in raw data. They are “fictions” (1941, 3 ff.) that we adopt as long as they successfully express the facts represented by the data. “[T]ime,” Kuhn writes, “is derived from endurance and change;” in the same vein, “cause and effect [are derived] from repeated interaction” (1941, 3). In this intuitive philosophical research Kuhn does not seek any account of the way concepts, unity, and data produce a proper scientific theory. He refers this matter to a practical attitude on the part of the researcher, who looks for unity and order. But how a specific arrangement of data gives rise to the concepts of space and time, and where that arrangement comes from, is not explained at all. What mostly interests him in this work is the relation between concepts and data, so as to answer questions about the “metaphysical possibilities of physics;” his own answers are guided by the intuitions of a student of physics relatively new to philosophy.
After this short essay, Kuhn did not abandon such questions, but he soon realized that it was necessary to understand scientific concepts and scientific explanation before providing an account of the nature of scientific truth. Already in 1943, Kuhn had revealed to his aunt Emma Fisher his interest in psychological epistemology. From 1943-45, he pursued such studies on his own and in a somewhat leisurely fashion. His study became more systematic in the Fall semester of 1945, when he took his first two graduate courses in philosophy. At this point, Kuhn began to adopt a recognizable philosophical language. This language derives partially from C. I. Lewis’ epistemology and modal logic, and partially from Russell’s and Whitehead’s ways of dealing with scientific concepts. It is worth mentioning that, although Russell is extensively discussed in Kuhn’s writings of 1945, it is Whitehead’s language that survives Kuhn’s penetrating criticism. Moreover, Whitehead’s language, along with Lewis’ work, are the bases on which Kuhn builds his early philosophical view about science, or more precisely, the views that preceded his first contact with the history of science.
Let us take as a case study Kuhn’s term paper for Donald C. Williams on “causal connexity.” In this paper, “An Analysis of Causal Connexity” (1945), Kuhn deals with causality, thereby focusing on a classic Humean theme in the philosophy and psychology of science. He examines Bertrand Russell’s definition of the law of causality (Russell 1929), and shows how that definition does not deal with all the meanings involved in the ordinary scientific usage of that notion. In other words, Russell’s definition is not as general as he intends it to be, and therefore is not a definition at all.
Russell’s definition is as follows: “Given any event e1, there is an event e2, and a time-interval t such that, whenever e1 occurs, e2 follows after an interval t” (1929, 183). Clearly, we must know what is meant by “event,” and why an interval t is necessary. In respect to this latter, Russell argues that cause and effect cannot be contiguous in time, or rather the separation itself between cause and effect cannot be explained at all (1929, 184-85). Furthermore, since infinitesimal time-intervals do not exist, any time-interval must be finite (Russell 1929, 187). Concerning what the term “event” refers to, Russell says that it is usually a universal, not a particular, and that it is something that recurs (1929, 186). But, Russell adds, we must be careful not to make a universal excessively “dense.” The more features we add to its definition, the more difficult it will be that the event occurs more than once. However, we cannot rely on a simple criterion of sameness such as that usually put forward in support of so trivial a definition of the law of causality as the principle “the same causes produce the same effects.” This only works, according to Russell, “in daily life and in the infancy of a science” (1929, 194), whereas modern physics relies on more strict criteria. Russell takes the law of gravitation as an example. This law is concerned with the relation between the configurations and velocities of a given (extensionless) particle at different instants. Causal connections thus take the form of a relation between two configurations separated by a time-interval, something properly described in terms of differential equations. It leads Russell to write that “sameness of relations […] is too simple a phrase” (1929, 195) and that it can be better reworded as “sameness of differential equations.”
For Kuhn, Russell is right to point to spatial and temporal coordinates as sufficient elements in establishing relations that science often takes as the foundations of a physical law. In so doing, Russell tightly links causal connexity to mathematical continuity. But Kuhn also shows that this conception is too simplistic. Sameness criteria, he says, also include restrictions that affect the use of differential equations, or, broadly speaking, restrictions concerning the way any sort of relation between quantities is admissible at all. “Restriction” means here that together with the predictability we expect of a causal connection—which is often provided by mathematical continuity—there is another essential feature of causal connexity without which that former cannot do. Kuhn thus writes:
[W]hatever the nature of the spatio-temporal field there are two portions to the notion of cause. One is the notion of predictability expressed in the quotation from Russel [sic]. It has been observed that under certain circumstances the validity of this notion may be analytically demonstrable. The other notion is simply that of the removal from the ontologically meaningful space-time field of certain types of event-particles which are conceivable and describable and therefore subsistent but which, if this analysis is correct, can never be existent (TSKP, “Analysis,” 12).
Kuhn summarizes this second feature with the phrase “excluded events,” something which refers to those events that, on principle, will never satisfy the proposed causal behavior (TSKP, 12-13). Causal connexity, as used in science, Kuhn emphasizes, employs both features.
Let us examine the examples Kuhn sets out in support of his own point of view. As Russell argued, it can be predicted where a given moving body (say, an extensionless particle) is going to be after a time-interval t (i.e., provided that its starting point is known beforehand). Velocity and acceleration of that moving body in a Newtonian framework can be reckoned by means of differential equations which involve time derivatives of position, with the restriction that any time derivative beyond the first two (i.e. the third derivative, expressing the rate of change of acceleration) must be equal to zero. But, in this case, it can also be said what that body is not going to do (i.e., where it is not going to be after t). That would be the “excluded event.” On the face of it, this is a trivial corollary. But it is not in fact trivial, as one recognizes if one explores the example in greater depth, as Kuhn did. It is mathematically admissible that the motion of two bodies that share an identical starting position and velocity comes finally to different end points, and, accordingly, that they follow divergent trajectories. This divergence is mathematically determinable in terms of the differences between the higher derivatives of the function assigned to each body. Without further restrictions, this is mathematically acceptable. But the phenomenon itself, Kuhn says, is not allowed in a Newtonian framework. Predictions within that framework must incorporate the previously mentioned restrictions on derivatives, so that the end point is the same in both cases. This potential divergence is the sort of “excluded event” Kuhn wanted to emphasize. In brief, Kuhn’s reference to the corollary mentioned above is not as trivial as it initially seemed. The essential conditions for laying down a scientific causal connexity include restrictionsconcerning the sort of formal predictive scheme that is permitted by our acquaintance with the phenomenal behavior we want to explain. Generally speaking, every form of scientific causal connexity involves taking the possibilities and impossibilities concerning the events we theorize about into account. A statement of the law of causation must pay attention to both features, predictability and restrictions, to be the alleged definition of causal connexity (TSKP, 13).
Kuhn also commented on another kind of causal relation by taking an example from the theory of gases (TSKP, 14-16). Gas theory employs expressions such as Boyle-Mariotte’s and Charles’ laws (or the gas equation) that are not time-dependent. For instance, by Boyle-Mariotte’s Law, at constant temperature, the volume of a gas sample is inversely proportional to its pressure. If we double the volume of that sample, the pressure will shrink to half its original pressure, but we are not allowed to say that the increase of volume is the cause and the reduction in pressure its effect, nor that the latter comes after the former. The organization of the causal relation is here quite different from that of Russell. It does not involve any time span, and the causal relation does not resemble the Newtonian case.
In conclusion, for Kuhn there is more to causal connexity as employed in science than Russell’s conception involves. The mathematical structure of prediction that Russell describes is certainly an essential ingredient of causality as employed in science. Yet, the specification of the sort of event involved in the causal behavior—i.e., of its necessary and sufficient features according to the causal behavior itself—is identically essential. As we will see below, Whitehead’s philosophy will be a stepping-stone to this criticism of Kuhn to Russell.
3. Kuhn, Scientific Objects,
and the Process of Physical Science
Whitehead’s philosophy helped Kuhn to build a convincing alternative to Russell regarding the nature of scientific concepts, and especially about causality as used in science. It is worth mentioning, however, that Whitehead himself preferred to neglect the issue about causality because, he said, it “raise[d] the memory of discussions based upon theories of nature which are alien to my own” (CN 146). All the same, his view about the role of objects and events in science was for Kuhn a useful philosophical perspective.
Whitehead relies on a “continuity of events” (CN 52, 76). For Whitehead an “event” is “the specific character [we discern] of a place through a period of time” (CN 52). Events have a passing nature, and, although sometimes exhibit a sharp edge, they often do not. In other words, an event overlaps a number of other events, so that they are all usually coextensive. The relation of extension between events (CN 58) leads to what Whitehead calls the “continuity of events,” which in turn constitutes the “continuity of nature” (CN 76). When events do not have a passing nature they are called “objects.” Thus, for example, given a certain place (such as a European capital’s main square), then a rainy afternoon, or the collective behavior of a mass of people in that place would be considered an event, whereas the City Hall or a cathedral located on the same square would be “objects.” For Whitehead this distinction is arbitrary. It is the outcome of an analysis in terms of a “materialistic theory of nature” and its three factors, time, space, and matter. But he warns that, even though this analysis is useful “for the purpose of expressing important laws of nature,” none of “these factors is posited for us in sense-awareness in concrete independence.” And he adds: “We perceive one unit factor in nature; and this factor is that something is going on then—there” (CN 75).
But, in actual fact, we need objects to arrange the continuity of events. The origin of scientific knowledge takes root at this point, says Whitehead (CN 158). Objects mark those passing entities (events) with an unmistakable stamp, themselves, and make events recognizable and comparable—otherwise events conserve their passing and subjective nature. Objects, for instance, acquire temporal and spatial features (i.e., they take shape, so to speak) with reference to certain events, and, in turn, make events recognizable and, frequently, intersubjective as well. As we go more deeply into the relations among objects and events, we discover that they can be investigated more precisely than they generally are in everyday intuition. We can select, for instance, what relations are more permanent and objective. The resulting objects and events are thus akin to a system of description, such as that usually presented in science. Whitehead calls these resulting objects scientific objects. They are the outcome of a thorough classification of physical objects in terms of other component objects; this classification seeks to provide a simple and uniform description of events by incorporating the most permanent and objective relations of events. It is important to underline that neither objects nor events are reducible to each other. In Whitehead’s words:
In fact the whole point of the search for scientific objects is the endeavour to obtain [a] simple expression of the characters of events. These scientific objects are not themselves merely formulae for calculation; because formulae must refer to things in nature, and the scientific objects are the things in nature to which formulae refers (CN 158).
In any case, Whitehead’s overall point of view is that science (and knowledge generally) provides the continuity of events—the continuity of nature—with order, classification, and stability. Science and its scientific objects are a sort of quintessence of this process. But if we try to understand a basic activity in that process, this is the progressive differentiation of events, which is marked by their gradual isolation, specification and classification. Exclusion plays a key role in this activity. Whitehead states that “every event is known as being related to other events which it does not include. This fact […] shows that exclusion is as positive a relation as inclusion” (CN 186). In other words, every complex state of nature is understood by including some events from among the set of events relevant to the state, while excluding others (CN 53). In science this process is merely more strict, specialized and permanent than in common sense.
As shown in the previous section, this general point of view is also evident in Kuhn’s “Analysis.” Let us turn again to his main examples. First of all, in the case of the gas sample, the causal behavior described by the gas equation or by gas laws—non-temporal laws, Kuhn recalls—relies directly on the notion of excluded events. Gas laws are laid down in such a way that they exclude the possibility of, e.g., a reduction of the volume of a gas sample without a simultaneous increase in pressure, when temperature is held constant (TSKP, “Analysis,” 16-17). Secondly, in the case of the moving body in a Newtonian framework we exclude some “event-particles,” as Kuhn calls them, following Whitehead. In Whitehead’s terms, an event-particle is an “ideally simple event […] indefinitely restricted both in spatial and in temporal extension, namely the instantaneous point” (PNK 33). Event-particles represent the possibilities of motion for an extensionless particle in any framework under conditions of mathematical continuity. Kuhn points out that, in this case, the use of differential equations is necessarily subject to the specification of excluded events. It is in terms of that specification that we will adjust the mathematical description to the expected causal behavior. In short, for Kuhn causal connexity, as used in science, is a sort of recurrent complex event whose variety of cases (involving time or not) finds a more general pattern in the Whiteheadian pair inclusion/exclusion than in Russell’s reduction to mathematical continuity.
In his “Analysis” (p. 8, n.), Kuhn names Whitehead’s The Concept of Nature (especially Chapters II-III) as a source of great inspiration for him, particularly with regard to the notion of the abstractive process by which event-particles are posited. In addition, Kuhn’s use of the notions of “event-particle” and “excluded event” clearly echoes Whitehead’s philosophical nomenclature. Nevertheless, Kuhn’s application of Whiteheadian notions was more complete later. In that respect, two further moments must be highlighted. The application is more definite in the first moment, when Kuhn employs a clearly Whiteheadian vocabulary, as for instance in his reference to “scientific objects.” This first moment was in 1947, when Kuhn was invited to participate in an experimental program of general education in science designed by the President of Harvard University, James B. Conant. This was Kuhn’s first contact with the history of science, and also the very beginning of his professional career as a historian (and later philosopher) of science. For the first meeting of the group, Kuhn wrote a summary of the “Objectives of a General Education Course in the Physical Sciences.” It was a sketch of the nature of physical science such as he saw it at that time. It must be emphasized that here Kuhn brands physical science as a “process” (TSKP, “Objectives,” 1, §I).
Kuhn’s understanding of the organization of this process relies upon typically Whiteheadian notions. According to Kuhn, the process of scientific research can be summed up in four stages:
1. The “pure classification” of “perceptual objects.”
2. The selection of “essential similarities” in “divergent phenomena.”
3. A “successive abstraction” aimed at isolating “scientific objects” (which differ from perceptual ones). This includes “increasing precision of definition including partial rejection of linguistic distinctions and of immediate sense data.”
4. The setting-up of a theoretical system and of a “conceptual structure.”
The references to “perceptual objects” and “scientific objects,” as well as Kuhn’s understanding of them as resulting from selective classification and abstraction, reveal Whitehead’s influence on Kuhn concerning the basic elements in science and how they are formulated.
The second moment in which Kuhn clearly adopts Whiteheadian notions is when he began his study of the history of science. As mentioned above, Kuhn used Science and the Modern World as a source of suggestive quotations, even as, gradually, he drew less and less on Whitehead’s actual thought. Yet, Kuhn’s first serious philosophical work, the eight Lowell Lectures of 1951 (never published), was still tentatively titled The Creation of Scientific Objects, although he finally changed it to The Quest for Physical Theory: Problems in the Methodology of Scientific Research. But even The Quest shows that Kuhn was still at least partially thinking in terms of Whiteheadian categories. In the second lecture, Kuhn begins by showing the medieval background to Galileo’s revolution in natural philosophy. But in the next two lectures Kuhn’s case studies are significantly different. Here, he deals with atoms and subtle fluids as ontological resources that serve as foundations for an indirect description of nature. In other words, Kuhn presents a study of how two kinds of scientific objects ground the understanding of a given range of natural phenomena (a group of “limiting events,” so to speak).
In summary, in this paper I have tried to show that Kuhn relied on Whitehead, at least in part, to launch his earliest attack on the empiricist view of physical concepts. The very idea of scientific objects was a stepping-stone to reach a different image of science. Since Kuhn’s mature work led to a breakthrough in our conception of science, an additional question seems relevant: Did Kuhn’s Whiteheadian views play any role in that rupture? This paper aims at making it easier to answer this question.
 See, e.g., Lucas 1989, 133.
 See the letter from C. H. Waddington to Thomas S. Kuhn, March 7th, 1963, 2, and Kuhn’s answer, October, 24th, 1963, 1, both of them in 4.16 of the Thomas S. Kuhn Papers in the MIT libraries (hereafter abbreviated as TSKP).
 See, e.g., Kuhn 1957, 123, and 1963, 350.
 For a thought-provoking way to put the difference between Kuhn and Whitehead see Steve Fuller 2000, 12, 302, and 423.
 In this sense, I partly follow Fuller (2000, 302 n. 89, and 423) in signaling Whitehead as a sure source for some of Kuhn’s views. However, I depart from Fuller’s interpretation in exploring Kuhn’s reading of texts other than Science and the Modern World. My reasoning for doing so is that Kuhn’s study of Whitehead is rooted in an earlier interest in the philosophy of science that came before his first contact with the history of science. Accordingly, Kuhn’s main Whiteheadian source was The Concept of Nature rather than Science and the Modern World.
 Letter from Kuhn to Emma K. Fisher, July 27, 1943, TSKP, 12.33.
 See the Harvard University Catalogue 1940/41, microfilmed, Harvard University Archives, Cambridge, Massachusetts, 234-35, for more information regarding their courses.
 On this stage of Kuhn’s intellectual development see Baltas et al. 2000, 262-63, 273.
 On Kuhn’s views of Bridgman see Kuhn’s letter to Edward T. Robinson, March 8th, 1965 (TSKP, 4.4); cf. Kuhn’s 7th (unpublished) Lowell Lecture (TSKP, 11.33, 40-41). Finally, Kuhn’s criticisms of Bridgman appear in his reading card at TSKP, 9.
 Kuhn’s letter to Fisher (TSKP, 12.33).
 TSKP, 9; Baltas et al. 2000, 305.
 TSKP, 7.
 TSKP, 7.
 For a complete list of his publications see Kuhn 2000, 326-35.
 See esp. Kuhn 1959 and 1961.
 TSKP, 1.3.
 TSKP, 5.
 This interpretation of Kuhn’s early view accords with that recently proposed by Peter Godfrey-Smith 2003, 177. However, his interpretation refers to a more advanced stage of Kuhn’s thought. For a thorough study of this issue, see Paul Hoyningen-Huene 1993, 56, 76-77, 262-63.
 On Kuhn’s early attitude toward Kant’s a priori, see his “The Metaphysical Possibilities of Physics,” 3-4. Again, Kuhn’s views are more akin to a Humean conceptions.
 See McHenry 2003, 161.
 Kuhn would later change his mind about this idea of causal connexity.
 There is indirect evidence in support of Hume (especially the Treatise of Human Nature, Bk. I, Pt. I, §I) as the probable source of Kuhn’s point of view in this matter. Kuhn affirms, for instance, that the way a physicist usually differentiates between true and false impressions by relying (among other more objective criteria) on a sort of innate belief that the true impression will have a greater liveliness (See “The Metaphysical Possibilities of Physics,” 2.) My italics call attention to the two words that have a distinctly Humean flavor (see Hume, Treatise on Human Nature, 1). This Humean influence, which can be traced also in Kuhn’s approach to the formation of scientific concepts in this essay, is scarcely surprising, given that he had studied Hume in Demos’ course. See Baltas et al. 2000, 264.
 I deal with Lewis’ influence on the young Kuhn in Mayoral (forthcoming).
 TSKP, 1.3 (Henceforth referred to as “Analysis.”)
 A cause is either a process or a static event. This second option is problematic, for it cannot be explained why a cause suddenly explodes into its effect. But if it is a process, then it must include an instant before the effect begins, or rather only the last part of that process (as well as the earliest part of the effect) would count as the cause itself, and this would no longer be the causal event that was initially considered (see Russell 1929, 184-85).
 However, Whitehead did use the notion of cause to enlighten the role of scientific objects in explaining appearances (PNK 182-89.) He, nevertheless, proceeded with caution in using that notion because causality and the objectionable “theories of the bifurcation of nature” were too closely related (CN 31-32).
 For everything I will say in this paragraph, see CN 144-58.
 On scientific objects see also PNK 93-98 and 186ff.
 See CN, especially 86 and 92ff.; cf. PNK 76, 121-23 and Chapter XIII.
 Kuhn also acknowledges Russell (1993, Chapter IV), but it is clear by now that he does not share his overall point of view. For more details about Kuhn’s criticisms of Russell, see Mayoral (forthcoming).
 TSKP, 1.4, dated May, 1947 (referred to hereafter as “Objectives”).
 TSKP, 1.4. My résumé is based on §I.1 of Kuhn’s outline, p. 1. Words, phrases and sentences into quotation marks are, of course, by Kuhn himself. To his general scheme, Kuhn adds many methodological details, especially concerning the role of generalizations and laws in the process of “successive abstraction” aimed at isolating “scientific objects”.
 Letter from Kuhn to Ralph Lowell, March 19th, 1950 (TSKP, 3.10).
 This was a series of eight lectures, March 3rd-30th, 1951 (TSKP, 11.33). The Structure of Scientific Revolutions would be the most famous by-product of them.
 Here Kuhn follows Alexandre Koyré (1940) very closely, and grounds that revolution in the geometrical treatment of physical situations that reaches back to ancient mathematics.
 In addition, they are good examples of “theories of the bifurcation of nature” (CN, Chapter II).
 I would like to express my thanks to the Institute Archives and Special Collections, Massachusetts Institute of Technology, for permission to quote from Kuhn’s unpublished papers, and to Ángel Faerna, Carlos Solís and Michel Weber for reading and commenting on previous drafts of this paper.
Works Cited and Further Readings
TSKP = Thomas S. Kuhn Papers 1922–1996. MC 240. Institute Archives and Special Collections, MIT Libraries, Cambridge, Massachusetts.
Baltas, Aristides, Kostas Gavroglu, Vassiliki Kindi, and Thomas S. Kuhn. 2000. “A Discussion with Thomas S. Kuhn,” in The Road since Structure: Philosophical Essays, 1970-1993, with an Autobiographical Interview, edited by J. Conant and J. Haugeland (Chicago, The University of Chicago Press), 256-323.
Crombie, Alistair, C. (ed.). 1963. Scientific Change (London, Heinemann).
Fuller, Steve. 2000. Thomas Kuhn: A Philosophical History for Our Times (Chicago, The University of Chicago Press).
Godfrey-Smith, Peter. 2003. Theory and Reality: An Introduction to the Philosophy of Science (Chicago, The University of Chicago Press).
Hahn, Lewis E., and Paul A. Schilpp, eds. 1998. The Philosophy of W. V. Quine, Revised Edition. The Library of Living Philosophers, Vol. XVIII (Chicago and La Salle, Open Court).
Hoyningen-Huene, Paul. 1993. Reconstructing Scientific Revolutions: Thomas S. Kuhn’s Philosophy of Science. Translation by Alexander T. Levine. Foreword by Thomas S. Kuhn (Chicago, The University of Chicago Press).
Koyré, Alexandre. 1940. Études galiléennes (París, Hermann).
Kuhn, Thomas S. 1957. The Copernican Revolution: Planetary Astronomy in the Development of Western Thought (Cambridge, Mass., Harvard University Press).
Kuhn, Thomas S. 1959. “The Essential Tension: Tradition and Innovation in Scientific Research,” in The Essential Tension: Selected Studies in Scientific Tradition and Change (Chicago, The University of Chicago Press), 225-39.
Kuhn, Thomas S. 1961. “The Function of Measurement in Modern Physical Science,” in The Essential Tension: Selected Studies in Scientific Tradition and Change (Chicago, The University of Chicago Press), 178-224.
Kuhn, Thomas S. 1962. The Structure of Scientific Revolutions (Chicago, The University of Chicago Press).
Kuhn, Thomas S. 1963. “The Function of Dogma in Scientific Research,” in Scientific Change, edited by A.C. Crombie (London, Heinemann), 347-69.
Kuhn, Thomas S. 1977. The Essential Tension: Selected Studies in Scientific Tradition and Change (Chicago, The University of Chicago Press).
Kuhn, Thomas S. 2000. The Road since Structure: Philosophical Essays, 1970-1993, with an Autobiographical Interview, edited by James Conant and John Haugeland (Chicago, The University of Chicago Press).
Lucas, George R., Jr. 1989. The Rehabilitation of Whitehead: An Analytic and Historical Assessment of Process Philosophy (Albany, State University of New York Press Press).
Mayoral, Juan V. Forthcoming. “Intensions, belief and science: Kuhn’s early philosophical outlook (1940–45)”
McHenry, Leemon. 2003. “Quine and Whitehead: Ontology and Methodology,” in Process and Analysis: Whitehead, Hartshorne, and the Analytic Tradition, edited by George W. Shields (Albany, State University of New York Press Press), 157-69.
Quine, Willard V. 1998. “Autobiography,” in The Philosophy of W. V. Quine, edited by L.E. Hahn and P.A. Schilpp (Chicago and La Salle, Open Court), 1-46.
Russell, Bertrand. 1929. “On the Notion of Cause,” in Mysticism and Logic, and Other Essays (New York, W. W. Norton & Co.).
Russell, Bertrand. 1993 . Our Knowledge of the External World (London, Routledge).
Juan Vicente Mayoral de Lucas
Department of History and Philosophy of Science
University of Cambridge (UK) and Darwin College, Cambridge
How to Cite this Article
Mayoral de Lucas, Juan Vicente, “Kuhn and Whitehead”, last modified 2008, The Whitehead Encyclopedia, Brian G. Henning and Joseph Petek (eds.), originally edited by Michel Weber and Will Desmond, URL = <http://encyclopedia.whiteheadresearch.org/entries/thematic/sociology-of-science/kuhn-and-whitehead/>.