[English Title] Is Hume a Causal Realist? An Analysis of the New Hume Debate
[Author] Luo Changjie, Lecturer of Institute of European and American Culture and Philosophy, Tianjin Foreign Studies University.
[Abstract] Hume's theory of causality has always been one of the focuses for researches on Hume. In recent years, the "New Hume Debate" has arisen between British-American scholars in the process of studying this theory. One side believes that Hume is a causal realist while the other side argues against this realist perspective. Analyzing and studying the "New Hume Debate" can not only enable us to understand the latest trends in international academic researches on Hume, but also help us to understand Hume's theory of causality more deeply.
[Keywords] New Hume Debate / Causality / Causal Realism / Anti-realism
In the past 30 years, there has been a long and bitter controversy about how to interpret Hume's theory of causality among British-American academic researchers. Most of the early researchers hold that Hume eventually reduces the causality to regular continuity between similar objects based on an empirical standpoint and empirical meaning theory. However, the new Humeans argue that Hume actually recognizes and believes in realistic causal necessity or causal force, which is not contrary to Hume's skeptical position. This view is called the skeptical causal realism ①, which has been refuted by some scholars and thus formed the continual "new Hume debate". This paper attempts to introduce the viewpoints of the pros and cons about the "new Hume debate", and comment on this whole debate.
I. New Hume Perspective: Skeptical Causal Realism
In the 1980s, G. Strawson (Galen Strawson) and J. Wright (John Wright) et al. were opposed to the traditional interpretation of Hume's theory of causality and raised a new interpretation for causal realism that Hume does not consider the causal relation equal to the constant conjunction between similar objects; instead, Hume actually holds causal necessity or causal force exists in the external world, and they are the root cause of this constant conjunction.
Strawson criticizes the traditional regularity theory has confused Hume's epistemological and ontological position in the issue of causality. According to this regularity theory, there has been an external world independent of the mind, and all of the casual relations are just a continuation of regularity. However, the regularity itself requires further reasons while the regularity theory has excluded any reason, thus it cannot explain why such regularity has existed in the world, rather than complete confusion. If the regularity is believed to exist in the world, we should also assume that there should be a real thing to provide a basis for the existence of this regularity, which is the inherent nature of the presentation of regularity. Hume's skepticism does not deny such supposition, and what it precisely rejects is the dogmatism of denying the existence of causal force in the external world. ②
Strawson further explains that Hume does believe in the inevitable conjunction of causality and the existence of causal force. He proves his points in two ways: 1) pointing out the limitations of Hume's theory; 2) raising the evidence mentioned in this paper to prove Hume has explicitly recognized the existence of causality.
In terms of causality, Hume holds that we do not have the impression of objective causality. Therefore, we cannot admit there should a causal force or inevitable conjunction in the real world. But what Strawson tries to prove is that Hume believes in such objective inevitable conjunction or the existence of causal force. Therefore, while defending this view of point, Strawson puts forward a new interpretation for Hume's theory of ideas. His arguments include the following aspects.
First, Hume's "relations of ideas" are beyond the scope of the theory of ideas.
Strawson notes that Hume has referred to a "relation of ideas" in his A Treatise of Human Nature Hume ③. In his opinion, although a relation of ideas has neither content nor real source of impression according to Hume, it can be referred to an external object. Of course, Hume also allows it to refer to real external objects or external causal forces. This opinion is completely incompatible with the rules of Hume's "theory of ideas", which has also explained Hume's many theories are beyond the scope of the strict theory of ideas.
Second, the differences between the concepts of "supposition" and "conception" mentioned in Hume's book have revealed the limitations of his theory of ideas.
When it comes to external objects, Hume says that: "We may suppose, but can never conceive a specific difference between an object and impression." ④ Pursuant to this, Strawson makes clear the differences between the concepts of "supposition" and "conception". According to Hume's argument, conceiving of anything must be formed with an idea that has content, which is very clear and has a source of impression, while supposing the existence of something does not need to form a clear idea. Strawson points out that we can obviously suppose the real existence of an object without having an impression or idea of this object. From the basic principles of Hume's theory of ideas, this argument seems ridiculous, but it just shows the limitations of Hume's theory of ideas. In addition to the theory of ideas, Hume's philosophy also contains other more important elements ⑤.
Strawson holds that since Hume admits the formation of a relation of ideas for external objects or the dispensability of forming a clear idea when an object is supposed to exist, then why not to understand Hume's theory of causality based on this point? We can also form a relation of ideas concerning causal force or causality. What this idea refers to is a substance by means of which the fact can present kind of regularity in a particular way, and it is also the substance that Hume called as the causal force actuating the operations of the whole universe.
Third, the meaning tension in Hume's philosophy has again revealed the limitations of the theory of ideas.
On one hand, Hume admits that we can use a relation of ideas to refer to an external object that really exists, or can intelligibly suppose the existence of external object; on the other hand, according to his theory of ideas, the mind can not conceive of a real external object. The mind has no real source of impression for the supposition of such objects. Therefore, it will be unintelligible to use the concept of causality to refer to an unknown causal force. Strawson regards this contradiction as the meaning tension in Hume's philosophy ⑦. But he believes that this tension is only a surface phenomenon. According to his explanation, in the era of Hume, the term "unintelligibility" does not refer to something that is internally contradictory or cannot exist, but simply meaning that there might be something that we cannot understand. Thus, although it will be unintelligible to use the concept of causality to refer to an unknown causal force in accordance with the theory of ideas, it does not deny the existence of the causal force but simply indicates that it is impossible for us to form an idea with particular contents. The argument of unintelligibility reflects Hume's skepticism, but not contradictory to his position in causal realism. ⑧
Strawson further explains Hume's position in causal realism by means of the evidence in this paper.
First, Hume's direct reference to causal force has shown his position in realism.
According to Hume's theory of ideas, we do not have an idea of "force" or "power" that can be used for referring to a substance existing in the external world. But he repeatedly talked about the causal force or causality existing in the external world, which seems that he has supposed the existence of the causal force. For example, Hume said: "Hence we may discover the reason, why no philosopher, who is rational and modest, has ever pretended to assign the ultimate cause of any natural operation, or to show distinctly the action of that power, which produces any single effect in the universe." ⑨ "Nature keeps us away from her secret, but only allows us to know a little external essence of the objects; For those forces and principles that the role of the objects is based on, the nature has hidden them from us." ⑩ Strawson believed that these expressions show no intention for Hume to deny causality, but suppose and believe in its existence.
Second, Hume's criticism on occasionalism has shown his position in realism.
As we know nothing about causal forces existing in external objects, some philosophers have attributed such forces existing in nature to God's will. Hume had raised his criticism on the viewpoints of these philosophers in his book. Thus, Strawson believed Hume's criticism on occasionalism indicates he does not deny the real existence of causal force. (11)
Third, Hume's discontent with the two definitions of the causes has hinted about his position in causal realism.
Hume defines the causes from two aspects: the first is to see the causal relation as constant conjunction or regular continuation; and the second is to interpret the causal relation as the mind habitually transferring from one object to another object. But Hume thinks his two definitions for causes are not perfect as such definitions can only be made from external and different substances, rather than give any proper definition for causes. (12) Strawson pointed out that the reason for these two definitions being imperfect is because they fully comply with Hume's idea of theories, "They cannot capture the true essence of causality" (13). Although there is a matter linking cause and effect in the external world, but due to limitations of the theory of ideas, we cannot conceive them with content. These two definitions have only conveyed the causality that we have known about, rather than the causality that really exists. Although Hume points out the ignorance of human, he never denied the real existence of the causality.
Just like Strawson, Wright attempts to limit the scope of theory of ideas while defending the causal realism, except that Wright attaches more importance to proving his position in realism in terms of the theory of nature belief.
The theory of nature belief first came from K. Smith (Kemp Smith), who is opposed to the traditional interpretation of regularity and points out the inappropriateness of this interpretation. (14) He holds that Hume's philosophy contains both negative skepticism and affirmative doctrine - "doctrine of nature belief". There has been a conflict between dogmatism and skepticism in philosophy, but Hume argues both theories will be a dead end, as we can also stand in a third position to recognize the limitations of rationality and take nature belief and common sense as the premise and the foundation for rational understanding. He makes clear the two systems: philosophical system and vulgar system, pointing out that only such vulgar system is feasible and self-consistent in a sense. This vulgar system makes us realize that both philosophers and ordinary people believe in the existence of the external world and the inevitable link between cause and effect. These two beliefs are nature beliefs. In other words, the basic belief cannot be proved but only trace its source from the structure of humanity. (15)
Wright has been deeply influenced by Smith's ideas. He further distinguishes the two theoretical levels in Hume's philosophy: philosophical level and natural level. He notes that from Hume's perspective, philosophical reflection should not be able to deny the natural belief, but will eventually succumb to the nature belief. "Belief in the existence of causality" is a nature belief and Hume's skepticism does not reject such belief; instead, "Our philosophical conclusion should be based on the reflection on the daily life."(16) In this sense, Wright considered the nature belief as the core of Hume's philosophy and advocated skepticism should be compatible with the theory of nature belief. Hume's theory of nature belief suggests that any person is holding his or her position in causal realism in daily life. This belief can withstand the most rigorous skepticism. However, Hume's theory of ideas was suspected and denied since it could not tolerate the theory of nature belief.
II. Defending the "Theory of Regularity": Winkler's Anti-realism Interpretation
Scholars represented by K. Winkler (Kenneth Winkler) objected to the above-mentioned interpretation of causal realism. Winkler pointed out that, although Hume has never denied the real existence of causal force or the inevitable conjunction of cause and effect, but he never asserts the existence of these things, as he does not believe in them. Realists criticized the traditional theory of regularity, and pointed out that denying the existence of mysterious force or mysterious conjunction had violated Hume's skepticism; however, Winkler holds that refusing to assert the existence of these things would have precisely accorded with Hume's skepticism. (17)
Winkler believes that the text evidence that realists used for verifying their views was not reliable. Defenders in favor of causal realism agreed that Hume has evidently admitted or believed in the existence of causal force in his writings, especially in his An Enquiry Concerning Human Understanding. They have cited a lot of Hume's texts to illustrate this point. Winkler points out that every text they cited is characterized by rather vague meanings in terms of admitting the existence of causal force. Therefore, the texts that realists cited are not sufficient to prove their point. (18)
Winkler emphasizes Hume's theory of ideas should be able to cover Hume's entire philosophy. Scholars holding realism believed that the scope of Hume's theory of ideas is very narrow, and cannot be used to understand all of Hume's philosophy. Nevertheless, Winkler stresses that the scope of this theory is universal, and its power cannot be underestimated. He refutes several main arguments of the realists.
First, the so-called differences in “supposition” and “conception” of the realists cannot prove the viewpoints of causal realism.
Winkler examines the true meaning of the term “supposition” used by people in the late 18th century. Richard Price believes that we can suppose something even in the paradoxical situation just as a mathematician tries to disprove something. In Winkler’s opinion, like Price, Hume means even contradiction can be supposed in using the concept of “supposition”. (19) Therefore, even if a certain point of view such as "existence of causal necessity" is absurd and incredible, but we can still make such supposition, which does not mean we do recognize the existence of causal necessity.
Second, "belief in the existence of causal force" is not a nature belief.
Winkler does not deny the existence of a nature belief theory in Hume’s philosophy, but he holds there is no evidence that Hume sees the objective existence of causal necessity as an inevitable belief. (20) Winkler believes that in Hume opinion, there are two ways to make a belief into nature belief: the belief is absolutely irresistible, or essential for human existence. According to this principle, "the belief in the existence of the external world" is a nature belief while "belief in the objective existence of causal conjunction" is not a nature belief.
According to J. Wright, Hume points out that people tend to project the inner feelings to the external world, making us believe there is a reason for the non-perceptible causal force to exist in nature in addition to the observed constant continuation. Therefore, the projective tendency that Hume describes on the mind indicates belief in the causality is a nature belief. In this regard, Winkler holds that Hume never says this projective tendency is irresistible, but Hume also mention a little bit of introspection is enough to suppress such tendencies that would only occur among children, poets and philosophers. (21)
Third, “intelligibility” and theory of ideas
In view of Strawson’s explanation on unintelligibility", Winkler reinterprets the “intelligibility” through an overall grasp of Hume's philosophy (22). He points out that there are two incompatible tendencies in Hume’s philosophy. The first tendency is to reject the “intelligibility” being a science idol. For example, Descartes, Malebranche and Leibniz regard a priori concept as the premise and foundation of intelligibility; Locke accepts the notion of substance mechanism, causing him to make a direct distinction between the first nature and the second nature. Hume is skeptical about the standards for "intelligibility" adopted by Descartes and Locke, so refutation of such “intelligibility” is the main topic for Hume’s two major works - A Treatise of Human Nature and An Enquiry Concerning Human Understanding; the second tendency is to advocate an idea would be true only when intelligibly associated with our experience. This means that Hume has resorted to a new standard for “intelligibility" to some extent. This standard is the first principle of Hume's theory of ideas, that is, an appropriate idea must have a source of impression that is similar to its impression.
Winkler holds that Strawson et al. may take their rejection on Hume’s "intelligibility" as an important part of their philosophy while he highlights the recurrence of Hume’s "intelligibility". Ultimately, Hume attempts to include all the arguments into the scope of his theory of ideas, and advocates all the concepts should be consistent with his theory of ideas.
Fourth, nature of Hume's skepticism.
Strawson and Wright et al believe that the traditional theory of regularity has portrayed Hume as a dogmatist, that is, he arbitrarily denies the real existence of causal force or arbitrarily claims that causality is nothing but a constant conjunction. Even in uncertain cases, a skeptic should allow for the real existence of causal force. If the causality that we’ve known is just a constant conjunction, a skeptic with reasonable curiosity will not have drawn the conclusion that “the causality is a constant conjunction”.
Winkler criticizes that this situation seems not to take place for Strawson et al. that Hume’s skepticism is to refuse asserting the real existence of causal force. But this argument has precisely reflected the spirit of Hume's skepticism. The explanation for traditional theory of regularity has well proved it. Hume never has to say the real causal force or causal conjunction does not exist, but just saying that we cannot conceive of it anyway, thus it would be enough for us not to believe in it. Strawson and other causal realists suppose the limitation of Hume’s idea about human rationality is just an epistemological limitation, for which Winkler holds this limitation is fundamentally covering the limitation of the whole idea of various activities such as conception, supposition or understanding. (23)
III. Comments on "New Hume Debate"
Since Hume, causality has become an important philosophical issue. The Scottish School of Common Sense has carried on a series of researches and arguments on Hume’s ideas, which turn out to be almost pointless so that the philosophical meaning of Hume’s causal theory cannot be fully recognized and highly valued until Immanuel Kant. Kant tries to see the concept of causality as a purely integrated concept, where he considers the causality as a priori integration form so as to solve the Hume problem. Modern analytic philosophers refuse to accept this priori form that they consider arbitrary. Instead, from the perspective of experience-based positivism, they identify the causality with the constant continuation between objects that can be observed, and claim Hume is a holder of theory of regularity by tracing the idea back to Hume. For example, Russell holds Hume has irrefutably demonstrated that the principle of induction cannot be inferred from experience or other logic principles. He fully endorses Hume to refuse to recognize the existence of causal necessity or force in the real world. He believes that the law of causality does not exist in reality, and that modern science will not be based on this principle. (24) However, according to K. Smith, more and more people believe that Hume's theory of causality has been unfairly treated, and begin to discover the naturalistic views implied in this doctrine, and recognize the belief of causal necessity is a nature belief. In other words, although rationality cannot prove the absolute reliability of causal reasoning, everyone is able to instinctively believe there is an inevitable connection between the so-called “cause” and “effect”. This naturalistic interpretation and the theory preferences of common sense realism since Moore are well integrated, making people withdraw from the interpretation of skepticism. Hence, it will not be inconceivable to see Hume as a causal realist. It is this new interpretation that has triggered the "new Hume debate" and caused us to review Hume’s theory of causality in the context of contemporary philosophy.
Specifically, there are two important reasons for the long and bitter "new Hume debate": 1) the complexity of Hume's theory of causality; 2) the ambiguity in related expressions in Hume’s papers.
1. Hume's analysis of causality involves multiple levels. He divides the analysis of causality into four parts: proximity, continuity, constant conjunction and causal necessity; he gives an explanation for the nature of causality that we can believe; in other words, when we have observed the constant conjunction between the two categories of objects in accordance with the customary, the occurrence of any new object similar to either of these two categories of objects will cause the mind to expect and believe in the occurrence of its constant accompaniment, and so on. Processing such a series of issues also involves Hume's entire theoretical background - theory of ideas and its theory of meaning. We refer all the theoretical efforts Hume has made around causality to the theory of causality.
According to Hume's multiple analysis on causality, we believe his theory of causality at least includes the following levels, and the relations between these levels is very complex and interrelated as if they are filled with tension. In terms of a level of the theory, Hume's argument is very clear. There will be trouble when we try to integrate each level and explain Hume's theory of causality on an overall basis - people often complain some explanations have misunderstood Hume or misrepresented his theory. It is different levels of processing and grasp that have led to the differences in overall interpretation, which have also mainly contributed to the continuing new Hume debate.
First, the basic principle of Hume's theory of ideas. Hume's theory of causality is restricted by the basic principle of his theory of ideas. This principle is: all the simple ideas come from a simple impression, which is also their precise reappearance. Thus, if the meaning or idea expressed from the concept or term we use has no original impression, the idea will be false, and the term used for expressing this idea will be incomprehensible.
Second, the skepticism of Hume. Causal necessity can neither be proved by relying on reasoning nor be confirmed with empirical observations; therefore, any idea claiming the concept of causality stems from these two approaches will be wrong and sophistical.
Third, Hume's positivism explanation for causality. Since we cannot find a causal link through rational proofing and empirical observation, then the causality we can understand will simply be regular proximity and continuity between similar objects.
Fourth, Hume's naturalistic explanation for causal necessity. Although what we can observe is only the reappearance of similar objects in similar continuity relations and proximity relations, the repeated observation on such similar relations will produce a tendency or new impression in the mind, which is the source of causal necessity or the idea and belief of the causal necessity.
Fifth, the direct reference approach that Hume has used when talking about the causal necessity. According to Hume, the notion of causal necessity refers to an internal impression of the mind, rather than something existing in the world. However, he often talks about a causal force or causal relation really existing in the external world, which seems that he supposes or believes in the existence of causal force. For example, he says: "Hence we may discover the reason, why no philosopher, who is rational and modest, has ever pretended to assign the ultimate cause of any natural operation, or to show distinctly the action of that power, which produces any single effect in the universe." (25)
Although researchers do not deny Hume's five basic ideas above, they have different understandings and focuses on such ideas. The new Humeans generally emphasize the fourth and fifth points but deny the first point that occupy an important position in Hume's theory of causality; yet regularity theorists emphasize the importance of the first point, and they see the second and third points as the inevitable conclusion of the first point.
2. When Hume argues the issue of causality, some of his expressions have shown certain ambiguity, leading to disagreements among people who learn about the intentions of his theory and triggering a fierce debate. As mentioned above, the new Humeans have made a new interpretation for distinction of the concepts of "supposition" and "conception" in Hume' works, the real meaning of "intelligibility" and the direct reference approach that Hume has used when talking about the causal force based on the idea of realism; on the contrary, the anti-realists represented by Winkler criticize the new interpretation above. These two groups of scholars have made a completely different understanding of a short speech delivered by Hume, even a sentence, and sailed into each other with sharp words, which has been commonly seen in the "new Hume debate". Although this debate concerns the overall situation, it is so trivial that the problem seems more complicated when people are attempting to clarify it.
So how do we view the ideas of realism and anti-realism in the new Hume debate?
To sum up, the new Humeans holding the view of causal realism mostly emphasize Hume's philosophy is a naturalist, while anti-realists holding the view of regularity theory pay more attention to the skepticism in Hume's philosophy; the new Humeans give publicity to the limitations of Hume's theory of ideas while the defenders of regularity theory highlight the importance of theory of ideas; the new Humeans are concerned about the exploration of inner meanings and even implications of some arguments in Hume's texts while the opponents adhere to the traditional understanding of the texts based on the background of the theory of ideas.
Based on the multi-level analysis on Hume's theory of causality, we will summarize the basic contents of this theory as follows: neither reasoning nor experience can provide us with the idea of causal necessity that independently exists, so when we use the concept of causality to refer to the objective causal necessity that is completely unknowable, and pretend to be aware of it, this concept will be unintelligible. In fact, the concept of causality that we can understand is merely the knowable regularity continuity and sensible inevitability, but it is such inherent feeling of inevitability that facilitates the mind to suppose and believe in a mysterious causal force existing in the external object by means of a completely natural "projection", and talk about it in a direct-reference way; nevertheless, since we have made it clear not to learn about such causal force by any means, then we will hold a completely imperturbable attitude toward the question of "whether it exists". In daily life, we can still rightfully talk about an objective causal force in a direct-reference way as long as its existence is not claimed or asserted.
As explained above, I believe Hume holds a completely agnostic attitude toward the question of "whether an objective causal necessity exists", thus it will be unreasonable to claim Hume is a causal realist. However, the drawbacks of the regularity theory are to merely emphasize Hume's skepticism interpretation for causality while ignoring his naturalistic interpretation for "causal necessity". Although Hume does not advocate the existence of objective causality, he neither refutes the inner necessity produced from the mind as illegal ideas nor argues against to talk about causality in a direct-reference way with daily languages. What he has been sticking to is: when talking about the causality in a direct-reference way, we should never assert that such objective necessity does exist and can be clearly recognized. Any attempt on such assertion will be reduced to fallacy.
NOTES:
①John Wright, The Sceptical Realism of David Hume, Minneapolis: University of Minnesota Press, 1983, introduction.
②Galen Strawson, The Secret Connexion, Oxford: Clarendon Press, 1989, pp. 21-22.
③Hume, A Treatise of Human Nature, Oxford: The Clarendon Press, 1975, p. 68.
④Hume, A Treatise of Human Nature, p. 241.
⑤Galen Strawson, The Secret Connexion, pp. 118-134.
⑥Galen Strawson, "David Hume: Objects and Power", in Read, R. & Richman, A. R. (eds.) The New Hume Debate, London: Routledge, 2000, pp. 36-37.
⑦Galen Strawson, The Secret Connexion, pp. 118-124.
⑧Galen Strawson, "David Hume: Objects and Power", in Read, R. & Richman, A. R. (eds.) The New Hume Debate, London: Routledge, 2000, p. 35.
⑨Hume, Enquiries Concerning Human Understanding and Concerning the Principles of Morals, Selby-Bigge. (ed.), P. H. Nidditch(Rev.), Oxford: Clarendon Press, 1975, p. 30.
⑩Hume, Enquiries Concerning Human Understanding and Concerning the Principles of Morals, p. 33.
(11)Galen Strawson, "David Hume: Objects and Power", p. 44.
(12)Hume, Enquiries Concerning Human Understanding and Concerning the Principles of Morals, p. 76.
(13)Galen Strawson, The Secret Connexion, p. 208.
(14)Kemp Smith, The Philosophy of David Hume, London: Macmillan and Co., 1941, p. 94.
(15)Kemp Smith, The Philosophy of David Hume, pp. 444-458.
(16)John Wright, "Hume's Causal Realism"[J],Read, R. & Richman, A. R. (ed.) The New Hume Debate, London: Routledge, 2000, p. 75.
(17)Kenneth Winkler, "The New Hume", in Read, R. & Richman, A. R. (eds.) The New Hume Debate, London: Routledge, 2000, pp. 52-53.
(18)Kenneth Winkler, "The New Hume", p. 54.
(19)Kenneth Winkler, "The New Hume", p. 64.
(20)Kenneth Winkler, "The New Hume", p. 68.
(21)Hume, A Treatise of Human Nature, Oxford: The Clarendon Press, 1975, p. 244.
(22)Kenneth Winkler, "The New Hume", p. 76.
(23)Kenneth Winkler, "The New Hume", p. 67.
(24)Bertrand Russell, "On the Notion of Cause", Proceedings of the Aristotelian Society, vol. 13, New Series, 1912-1913, pp. 1-26.
(25)Hume, Enquiries Concerning Human Understanding and Concerning the Principles of Morals, p. 30.