HUME'S REALITY: A LESSON IN CAUSALITY Stefanie Rocknak Hartwick College, Oneonta NY 13820 In Book I, III §9 of the Treatise, Hume makes the claim that "[all general] belief arises only from causation" (T 107). Following, he makes the even stronger claim that all general beliefs are to be thought of as beliefs in reality, and thus, all belief in reality is dependent on pre-established beliefs in both specific causal relations and the causal relation in general1 (T 108). In the first part of this paper, I explain Hume's motivation behind both claims, while in the second part, I argue that to some extent, Hume is correct; our belief in "reality"-a notion to be defined-is fundamentally dependent on a preestablished belief in the general notion of cause and effect and a cache of specific causal relations. Thus, epistemologically speaking, we must conclude that our notion of "reality" is intrinsically causal. Part I. A Sketch of Hume's Position § 1 Cause and Effect and Reality: A General Account To explain the pivotal role that causality plays in our belief in reality, Hume provides an example that would serve us well to review; "'tis evident," he writes, that: one of the best relicks a devotee cou'd procure, wou'd be the handiwork of a saint; and if his cloaths and furniture are ever to be consider'd in this light, 'tis because they were once at his disposal, and were mov'd and affected by him; in which respect they are to be consider'd as imperfect effects, and as connected with him by a shorter chain of consequences then any of those, from which we learn the reality of his existence. (T 101; emphasis added). 1 However, due to length considerations, I will not explain here how Hume thinks we initially establish this foundation of causal beliefs. See my book (in progress) for more detail: Imagined Causes: An Account of Hume's Objects in Book I of the Treatise. 2 In other words, according to Hume, if a devotee has an impression or impressions2 of a Saint's personal items, [s]he is more inclined to believe in the existence of the Saint, but only in light of his/her belief that the Saint's items are the caused and "imperfect effects" of his actually being alive. In more abstract terms, this means that according to this example, belief in the existence of some thing , is a function of our belief in specific causal relationships, where in this case, the given consequent (e.g. the Saint's personal items, or what we can refer to as Y) is present as an impression. Yet Hume's thoughts are not specific to just this example. Rather, they square with his more general conception of belief; note one of his earlier remarks that makes this clear: "belief may be most accurately defin'd a LIVELY IDEA RELATED TO OR ASSOCIATED WITH A PRESENT IMPRESSION" (T 96; boldness added). In other words, the impression of the consequent (Y) leads to belief in the idea of the antecedent (e.g. the idea of the Saint actually existing, namely, the idea of X, or what we may refer to as X`).3 In still other words, with the presence of the given impression, in this case, as a consequent Y, one is led to conclude that there must be a cause, X,4 which leads one to believe in the idea of X. Moreover, it would seem that Hume thinks that wherever there is a belief in a certain causal relationship and the antecedent is present as an impression, then the idea of the consequent will immediately be thought of in a lively fashion, and thus, believed in. For 2 Generally speaking, according to Hume an "impression" is any information that we receive from our five senses. Impressions may also be "reflexions" (T 7), but we need not take them into account here. 3 That is, Hume clearly defines belief here and elsewhere as an "enlivened" idea, and thus, belief is not an impression (also see T 101, 103, 116, 119). 4 Where X is, evidently, believed to be a necessary and sufficient cause of Y, that is, without X, there would be no Y and if there is X, there must be Y. In still other words, Hume seems to be assuming here that causal relationships are biconditionals (e.g.[ (X  Y) & (Y  X)]). Clearly this is problematic. For instance, although we may believe that rain causes the road to get wet, seeing a wet road does not necessarily imply that it rained (e.g. a fire hydrant could have burst nearby). However, we need not pursue the implications of this problem here. Moreover, as suggested in my opening remarks, in order for this to work, the given causal relationships must already be believed in. That is, one could not come to believe in X' in the presence of Y if one did not already believe in the relation of [ (X  Y) & (Y  X)]). This means that the account of belief given above must be characterized as general belief, which, as such, is dependent on a set of a more particular kind of belief, namely, beliefs in specific causal relations. 3 instance, if I see food on the table, which I believe will cause me to no longer be hungry, I will believe that in the near future I will no longer be hungry. Thus in short, the formula is as follows: if one experiences a given impression p, where p may serve either as an antecedent or consequent (or trivially, both), p will produce a lively idea of q, namely, q,` where q` is the idea of the antecedent if p is a consequent, present as an impression. and alternatively, q` is the idea of a consequent where p is the antecedent, present as an impression. And thus, Hume announces: "This phaenomenon clearly proves, that a present impression with a relation of causation may enliven any idea, and consequently, produce belief or assent, according to the present definition of it." (T 101; emphasis added). As such, Hume concludes that all general belief is a function of our already-established beliefs in causal relations,5 and thus, concomitantly, a belief in the relation of causation in general. Accordingly, the visual illustration of this phenomenon may be characterized as follows: 5 See footnote 2. 4 Figure 1: Ideas Enlivened in Respect to Causal Relationships Case 1: Antecedent Present to the Senses (the causal relationship of p iff q already believed in) cause effect p q q' Case 2: Consequent Present to the Senses (the causal relationship of p iff q already believed in) cause effect p q p' Not present as an impression Production of an enlivened idea that, as such, is believed in Antecedent impression; present to the senses Consequent Impression; present to the senses Production of enlivened idea, that as such, is believed in Antecedent impression; not present to the senses 5 §2 Two Levels of Reality Further on in §9 (T 108-110), Hume claims-in so many words-that: 1. Belief in reality = all general beliefs 2. Belief in reality is based on the relation of cause and effect 3. Therefore, all general beliefs are based on the relation of cause and effect To begin to see how and why he comes to this conclusion, first note that according to Hume, there are certain memories that, if checked against the collection of impressions that are actually available to us, would "resemble [such]...immediate impression[s]." (T 108) As such, these memories are easily distinguishable from "the mere fictions of the imagination" (T 108), which cannot be checked against actual impressions. For instance, I cannot compare my idea of a unicorn with actual impressions of a unicorn, since such impressions are simply not available to me. However, I can compare my idea of a black terrier with actual impressions of a black terrier; to do so, I would simply have to find someone who owns this kind of dog. Immediately after establishing this distinction between what is remembered v. what is merely imagined, Hume explains that we take our various present impressions and those remembered ideas that could, if checked, correspond to actual impressions (such as, say, an idea of a black terrier) and we form a "system" which constitutes our "reality." (T 108) Yet Hume immediately continues after establishing as much: But the mind stops not here. For finding that with this system of perceptions, there is another connected by custom, or if you will, by the relation of cause and effect, it proceeds to the consideration of their ideas; and as it feels that 'tis in a manner necessarily determin'd to view these particular ideas, and that the custom or relation, by which it is determin'd, admits not of the least change, it forms them into a new system, which it likewise dignifies with the title of realities. (T 108; emphasis added). In other words, we must realize that Hume introduces two epistemological levels here, or what he refers to as "systems." The first system, constituted by perceptions (namely, 6 impressions and ideas) emerges on a more immediate level, which, as noted, appeals to our memory and our ability to check it against impressions. At the second level however, the relation of cause and effect is brought to bear, which somehow, in a regular, determined fashion, forms a new system, which invokes "reality" proper. Moreover, and important to note, the first "immediate" system seems to be entirely dependent on the second, "causal," system. To better understand what Hume has in mind here by these two systems, consider the following remark: "'Tis the latter principle [based on cause and effect], which peoples the world, and brings us acquainted with such existences, as by their removal in time and place, lie beyond the reaches of the senses and memory." (T 108) In other words, as noted, the second, reflective level allows us to conceive of and believe in the reality of places that we have never been to, people we have never met, and thus, things that we have never formed actual impressions of. As such, this reality could not possibly belong to the realm of "memory and the senses," for in this case, nothing has been sensed, and thus, nothing has been remembered in terms of impressions either. This means that the system of causal judgments constitutes a projected reality, but, according to Hume, an accurate reality nevertheless. He explains further as follows: By means [of this second system] I paint the universe in my imagination, and fix my attention on any part of it that I please. I form an idea of ROME, which I neither see nor remember; but which is connected with such impressions as I remember to have received from the conversation and books of travelers and historians. (T 108). That is, Hume is somehow able to project, or imagine an idea of Rome although he has never experienced it first hand, and thus, he cannot be said to remember it, much less have had an impression of it. Moreover, important to note, such ideas (e.g. the idea of Rome) are imagined based on the relation of cause and effect. Yet, one might ask, just how does the human being imagine people, places, events, etc. "based on" the relation of 7 cause and effect? Hume answers by claiming that although the idea of Rome is indeed imagined, thanks to the "custom and the relation of cause and effect," it is to be distinguished from the other ideas that are "merely the offspring of the imagination." (T 108). In other words, what is imagined is causally justified, and in fact, contributes to the fabric of reality, but what is "merely" imagined is a function of the fantasy,6 and as a result, does not help constitute reality. For instance, although I may have never been to Prague, and thus, the idea that I have of it is imagined, it nevertheless constitutes what I take to be reality. However, this is not the same as saying: "I have never seen a unicorn, and thus, the idea I have of it is imagined. Nevertheless, this idea constitutes what I take to be reality." Rather, according to Hume, the difference between my imagined idea of Prague vs. my imagined idea of a unicorn would lie in the fact that the former is based on a "present impression" that fits into a pre-established belief in a particular causal relation-as was shown to be the formula in §1-7 while the latter is not. For instance, if in the past I have discovered that certain people are trustworthy, I will tend to believe that the stories that they tell me are true (where the specific causal relation would be: If a person is trustworthy, then one should believe in his/her accounts). As a result, I will tend to believe their assertions that Prague exists, regardless if I hear these stories first hand, or say, read them in a National Geographic magazine. Thus, in this case, the "present impression" so crucial to Hume's conception of belief outlined in §1 of this paper, would be my hearing or reading the stories of Prague, where again, the causal relationship would be: one of the effects of trustworthy people is their true accounts. However, in the case of the unicorn, I have no present impression to lead me to infer the unicorn's true existence in such a (lively) way that I would believe in it. However, it seems that I would be compelled to believe in unicorns if the people that I trust suddenly came home with 6 Recall that the Medievals employed a somewhat similar distinction between the imagination and fantasy (see Brann 1990, p. 21) 7 Recall, in particular, Figure 1. 8 descriptions of unicorns that they claimed they actually saw; in this case, their stories would cause me to believe in the unicorn's existence. Finally, we must realize that according to Hume, without the second, causal system of reality in place, we could never comprehend a reality that existed beyond our immediate impressions and memory-our world, as such, would be severely limited. Moreover, and crucial to note, the very idea of "if I had an impression of  such that this impression corresponds to my memory of , then  exists" is nothing more than a belief in a causal relation. Thus, "immediate reality" is also intrinsically causal in nature, and thus, it seems that Hume may indeed conclude that all beliefs in reality are based on the relation of cause and effect (T 108-110).8 With this account in mind we may once again illustrate his thought be way of a diagram: 8 Keep in mind that to some degree, Hume comes to this conclusion by way of ruling out contiguity and resemblance as being more epistemologically foundational than cause and effect. But we need not take this argument into account here. 9 Figure 2 Two kinds of Reality Immediate Reality Consists of memories that can be verified with impressions Removed (reflected) Reality: Necessarily based on the relation of cause and effect p q q' Present as an impression: believable story about Prague Imagination of enlivened idea of Prague Not present as an impression: the real Prague Example: Causal Relation: If trustworthy people claim that x exists, then x exists 10 Part II. A Brief Defense of Hume Is it actually the case then, that our belief in reality is based on Hume's two fundamental systems? In particular, in order to believe in reality, must we either [A] Actually experience some thing or event  via our five senses and/or [B] Project a reality that is based on pre-established beliefs in causal relations? It seems that we would be hardpressed to say that this is not the case. For although our belief in reality-where, loosely put, "reality" would consist in all that we believe to actually exist-might be based on certain epistemological features in addition to [A] and [B], I do not think that we could argue that any coherent belief system in reality is not in some respect, based on [A] and [B]. In other words, although we might argue that [A] and [B] are not sufficient for a belief system in reality, we could not coherently argue that [A] and [B] are not necessary for a belief system in reality. To begin to see why in the time allowed, simply consider the following thought experiments: Assume that you are now in some place other than your home, say, a lecture hall. Do you believe that your home continues to exist, regardless? Why? Perhaps because you have actually experienced your home by way of your senses, e.g, you have, at least, seen it and touched it. If this is the case then, you would be appealing to [A]. In particular, you would be appealing to certain memories of empirical sensations (namely, Humean "impressions") of your home that, if checked against actual, similar sensations, would assure you that your home really exists. However, as noted earlier, realize that this belief is itself based on a pre-established belief in a causal relation, namely, if one successfully checks certain memories of his/her home against actual impressions of your home, then [s]he may justifiably assume it exists. 11 Now assume that you have never been to Iceland: Do you believe that this place exists? Why? Because you have seen pictures of it and/or television footage, and/or know someone who has actually been to Iceland? But if this the case, then you are simply appealing to system [B]; namely, a set of pre-established beliefs in causal relations, that, when paired with certain "lively impressions" (namely, television footage, pictures, or stories told by friends) cause you to believe in Iceland. For, it seems, we almost unconsciously conclude that if there are genuine (namely, not computer generated) pictures or TV footage of a place, then the place exists. Or, as noted in Part I of this paper, if a trusted friend tells a story about a place existing, then we tend to believe that that place exists. Thus, although I have surely not presented a watertight case in such a short amount of time, I hope that the audience may be more convinced that Hume's account of reality touches on a fundamental aspect of human epistemology, namely, the idea that all our beliefs in reality are, in fact, based on a pre-established belief in the relation of causality and a collection of various causal relations.9 9 Where just what the collection of varying causal relations consist of, would, to some degree, depend on experience. Further, note that at least Carnap (1928) and Quine (1965) would make similar arguments. 12 References Brann, Eva. The World of Imagination: Sum and Substance. Savage, MD: Rowman & Littlefield, 1990. Carnap, Rudolf. The Logical Structure of the World; Pseudo problems in Philosophy. Second edition. Translated by Rolf A. George. 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