Copy Principle Research Articles

An Appraisal of Hume’s Theory of Causation: Is Hume a Causal Realist?

Hume’s construal of causation historically lays out a philosophical puzzle towards realism and anti-realism; in fact, this scholarship deliberately offers a bit of thoughts for causal realism - in virtue of the Old Hume and New Hume debate, as well as its contextual language. Nevertheless, this dialectic is significantly underestimated by plenty of counterexamples such as empiricism, liberty and necessity, the immateriality of the soul, and copy principle. In response to these brainstorming facets, this research article intends to determine that Hume is a causal anti-realist; I have, in turn, explored three supporting arguments to defend the compelling idea: conventional manifestation of causality - Hume’s advocacy of necessary connection - the idea of liberty and necessity. However, this critical study is restricted to examine other substantial reflections on those which are included in the compositions of Treatise and Enquiry. 

Hume's Missing Shade of Blue: A New Solution

What to do with the missing shade of blue (MSB)? Some have argued that Hume's famous thought experiment undermines his central doctrine – the ‘copy principle’ – such that he should have revised his whole theory in light of it. Others contend that the MSB is not a true or actual counterexample to the copy principle, but merely an apparent or conceivable one, so that he had no such obligation to revise. In this essay, I argue that even if the MSB is a true counterexample, Hume would not have been obligated to revise his theory, given methodological resources he makes available to himself elsewhere in his work and his overarching empiricist aims. And I offer a new suggestion for why he might have included and even highlighted the MSB in his writings despite its being so very vexing and peculiar.

Character and Causation: Hume's Philosophy of Action by Constantine Sandis

Reviewed by: Character and Causation: Hume's Philosophy of Action by Constantine Sandis David Landy Constantine Sandis. Character and Causation: Hume's Philosophy of Action. London and New York: Routledge, 2019. Pp. xiii +148. Cloth, $140.00. Constantine Sandis's suggestive new book consists of a series of discrete studies of aspects of Hume's philosophical system that culminate in an argument for the conclusion that "on Hume's view . . . we are only morally responsible for that subset of actions that have been motivated by our character traits" (90). That final conclusion is the end of a wide-ranging and systematic argument that feels too compressed in the scant one-hundred and twenty-three pages in which it is presented, especially since the philosophical and exegetical theses that Sandis presents along the way are intriguing and receive just enough support to make the reader long for a more robust consideration of them. Sandis's grand argument begins with the familiar approach of understanding Hume's Copy Principle as placing strict limits on the possible contents of our mental representations, thereby requiring Hume to revise our understanding of our own ideas. Sandis dubs this "soft conceptual revisionism" (2). In the early chapters of the book, the most important result that this approach yields is Hume's revision of our concept of necessary connection [End Page 406] to comprise only constant conjunction and temporal priority. The upshot of Sandis's discussion is to earn Hume a sense of 'necessity' and 'causation' that meets his criterion of meaningfulness and grounds the aforementioned account of action. Actions turn out to be those bodily movements with certain causes, properly construed, as either acts of will or character traits. Another important piece of Sandis's argument is his provocative claim that "a belief just is the feeling or sentiment accompanying an idea" (23), which "firm conception consists in feeling that something is the case" (24). At first blush, Sandis appears to make the radically heterodox claim that Hume holds that there is a distinct impression that is annexed to, accompanies, all believed ideas, despite the fact that Hume explicitly argues against that thesis (App 3–9/SBN 624–27). Upon closer inspection, however, Sandis denies the radical heterodoxy (24), and his actual claim is more anodyne. Despite his continued reference to belief as a sentiment or feeling, which terms Hume uses to denote distinct impressions (e.g. T 2.1.11.7/SBN 318–19 and T 1.1.1.1/SBN 1–2.), Sandis's actual claim appears to be that we should understand Hume's use of 'belief' to refer to the liveliness of these enlivened ideas, rather than the ideas themselves. What Sandis takes that nominalization to earn him is that beliefs, including moral beliefs, can produce action alone because they "are all sentiments" (99), and Hume is free to hold that we can be motivated directly by at least some of our beliefs, without the need for an additional conative perception. (In this sense, Sandis takes Hume to be non-Humean about motivation.) That is, Sandis holds that the liveliness of some of our ideas can itself be the cause (in the proper Humean sense) of some of our actions. That thesis is significant for Sandis insofar as discovering the cause of our actions brings to bear the question of the disappearing agent (78): if our actions have causes outside of our control, even if these causes are literally parts of us, then in what sense are we responsible for those actions? Sandis's answer on Hume's behalf is that while some actions are bodily movements caused by particular volitional perceptions (acts of will), we are only responsible for those actions that are also caused by manifestations of the long-term dispositions that constitute a person's character. In support of this answer, Sandis also advocates for a revisionist understanding of Hume's account of the self as a bundle of perceptions (chapter 4), an interpretation of Hume's notion of character as long-term behavioral dispositions (chapter 5), a rejection on Hume's behalf of what Sandis calls the Conflating View of Motivating Reasons—the thesis that the reasons for...

Précis of Hume's True Scepticism

Précis of Hume's True Scepticism Donald C. Ainslie (bio) In Hume's True Scepticism (hereafter "HTS"), I offer a new interpretation of David Hume's epistemology and philosophy of mind as presented in A Treatise of Human Nature.1 I approach this task by developing what I take to be the first comprehensive2 investigation of Part 4 of Book 1. The arguments Hume offers there have frequently been addressed by the secondary literature in a piecemeal fashion, especially his account of personal identity and of our belief in the external world. But I argue in HTS that they should be read as a sustained investigation of the human temptation to form philosophical systems. Consider its title: "Of the sceptical and other systems of philosophy" (emphasis added). Hume, I suggest, is interested both in defending his own preferred approach to what he calls the "science of human nature" (T Intro. 9, 1.1.1.12, 1.2.5.19, 1.3.8.2; SBN xviii, 7, 60, 98), and explaining how the mind's structures lead other philosophers to succumb to certain characteristic errors. The outcome is a "true" scepticism (T 1.4.7.14; SBN 273) in which we acknowledge that philosophical beliefs about the mind are not fundamentally different in kind from vulgar beliefs about the world: both depend on the associative tendencies built in to human nature and thus, do not equip us to penetrate into how things are independently of our cognitive capacities—their "real nature and operations" (T 1.2.5.25–26; SBN 63–64). It follows that there is no "obligation" to philosophize (T 1.4.7.10; SBN 270), and it is domesticated into an activity that should be pursued only by those with an inclination for it (T 1.4.7.12; SBN 270–71). A central theme in HTS is the role of reflection in philosophy and in everyday life. I suggest that Hume holds that in everyday life, the "vulgar"—all of us most of the time (T 1.4.2.36; SBN 205)—are fully engaged by our reasoning and sensing. Thus, we are not normally aware of the mental mechanisms that Hume details throughout the Treatise, nor are we even aware of the perceptions that he takes to be the vehicles for our mental lives. Rather, we typically [End Page 95] remain focused solely on that which our reasonings and sensings concern. In calculating a tip at a restaurant, for example, our thoughts concern only the bill. In going about our business in the world, we take ourselves to be moving in the same world of tables and chairs and trees as everyone else. In chapter 2, I argue that even this 'taking' is something we are not normally aware of. Instead, we carry along a mostly unarticulated and unrecognized assumption that we are in touch with the world. I spend a fair amount of time in chapters 2 and 3 showing how Hume understands the mind to produce this assumption. I argue that a proper interpretation of the relevant material (especially T 1.2 and 1.4.2) requires that we see his empiricist theory of representation as being much more flexible than it is often taken to be, where the so-called copy principle—the requirement that every simple idea be derived from a prior simple impression—is treated dogmatically, as if Hume himself does not immediately qualify it, first, with the "missing shade of blue" (T 1.1.1.10; SBN 5–6), and shortly thereafter with his account of general ideas (T 1.1.7; SBN 17–25). In the latter, Hume argues that we are able to think of universals, despite never having impressions of them, because the imagination associates ideas of particular members of the kind in an appropriately structured manner when accompanied by a linguistic token. I take the linguistic dimension of Hume's account to be especially significant, in that it brings in a normative and social dimension (T 3.2.2.10; SBN 490) to his otherwise narrowly naturalistic and individualistic treatment of the mind. I argue that, for Hume, this set of associative and linguistic...

Sensation, Nominalism, and the Elements of Experience

ABSTRACTCharles Sanders Peirce and Maurice Merleau-Ponty raise the same objection to British empiricism: its foundational tenet—captured in Hume's Copy Principle, that all of our ideas are fainter copies of our impressions—is nominalist. It is not clear what this objection amounts to, however, since the British empiricists are nominalists of one stripe or another. I canvass different ways to construe this objection. Three different construals of it fail. A fourth construal succeeds, but in a way that leaves the foundational tenet of British empiricism intact. The problem is not that the tenet is false (it may be) but that it cannot be adopted as a foundation on which to build a philosophical account of those elements of an experience that are contributed by the world and those that are contributed by the experiencing subject.

Recent Scholarship on Hume's Theory of Mental Representation

AbstractIn a recent paper, Karl Schafer argues that Hume's theory of mental representation has two distinct components, unified by their shared feature of having accuracy conditions. As Schafer sees it, simple and complex ideas represent the intrinsic imagistic features of their objects whereas abstract ideas represent the relations or structures in which multiple objects stand. This distinction, however, is untenable for at least two related reasons. Firstly, complex ideas represent the relations or structures in which the impressions that are the objects of their simple components stand. Secondly, abstract ideas are themselves instances of complex ideas. I draw two important conclusions from these facts. Firstly, contra Schafer and Garrett (to whom Schafer responds), the Copy Principle, properly emended, constitutes the entirety of Hume's theory of mental representation. Secondly, whereas paradigm examples of complex ideas, e.g. ideas of spatial and temporal complexes, are structured by relations of contiguity, abstract ideas are those complex ideas instead structured by relations of resemblance. As such, they represent their objects not as spatially or temporally contiguous but rather as resembling.

Character and Causation: Hume's Philosophy of Action by Constantine Sandis

Reviewed by: Character and Causation: Hume's Philosophy of Action by Constantine Sandis Elizabeth S. Radcliffe Constantine Sandis. Character and Causation: Hume's Philosophy of Action. New York and Abingdon: Routledge, 2019. Pp. 148. Cloth ISBN 9781138283787, $140. In Character and Causation: Hume's Philosophy of Action, Constantine Sandis takes Hume's empiricist tenet that all meaningful ideas copy impressions as the key to understanding his general philosophy. Sandis then applies "the Copy Principle" to Hume's view of persons and their actions. Portraying Hume's approach (at least in the Treatise) as one of conceptual revision, the result, Sandis says, is that our ideas of persons, reasons, causality, agency, free will, and other related concepts have ordinary meanings (not the abstruse philosophical ones) without ontological implications. The author describes his book as a series of connected essays. The chapters work together to present an anti-metaphysical, naturalistic, and nonskeptical picture of Hume's action theory. Each chapter is readable and trim, but the book covers a great deal of territory in a short space. At times, I craved more detailed arguments and help understanding the views in Sandis's original portrait of Hume. However, both Hume scholars and action theorists will surely find this book thought-provoking and worth grappling with. A brief epilogue discusses how Hume's "soft revisionism" bears on contemporary discussions of agency and action. Sandis takes Hume's project to be one of establishing what we ordinarily mean in using the terms that stand for problematic concepts like necessity and self. It is not a project of determining what we can properly mean, since expressions just have meanings; they are neither correct nor incorrect. (There are echoes of Wittgenstein throughout the book, and Sandis invokes him explicitly in Hume's [End Page 139] defense in chapter 3, "Necessity, Power, and Freedom.") Furthermore, Hume's is not a project of investigating the ontology of causation, agency, and so on. Consequently, Sandis suggests, debates, such as the "new Hume" debate, which revolve around questions like whether Hume was a realist, anti-realist, quasi-realist, or skeptical realist, are misguided. Causation involves the idea of necessary connection, of which we have no impression. So, Sandis argues, since we cannot meaningfully say anything about necessary connection, we have no idea to project onto the world and nothing to affrm or to deny. "Hume's conceptual revisionism about necessity thus tempers both skepticism and metaphysical realism in a move made routinely [by Hume] in relation to every major philosophical controversy of his day" (47). In much of the book, Sandis applies this revisionist interpretation of Hume to topics of free will, substance, self, identity, and motivation and morality. At the heart of Sandis's reading of Hume's action theory is the notion of agency, which is rarely emphasized in analyses of Hume. Sandis develops this conception of agency, first, via discussion of necessity and freedom. Necessitation of action and liberty are easily compatible because of the way Hume defines each within his practice of conceptual reform. He describes cause in terms of constant conjunction of experiences, and necessity in terms of human expectation. Liberty, in his terms, is the ability to do as we will (desire), not the capacity to do anything regardless of the will. Thus, I am free when my motives are regularly conjoined with actions such that observers can predict certain behaviors on my part. Second, agency is tied to the self (mind) and personal identity. In the case of self (and substance), we have no idea of it apart from the ideas of varying qualities; the notion of an uninterrupted self or substance over time is a fiction. However, Sandis argues, Hume offers revised ideas of the self, of substance, and of identity, which follow from Hume's own "theory of meaning" (69). I cannot trace all the twists Hume's discussion of personal identity takes, but in the end, Sandis thinks it "allows us to talk of 'self' and 'identity' in a way that requires nothing beyond the sort of casual observations that he allows for across all his works" (69)—simply as qualities we suppose are tightly connected by relations of contiguity and...

Simple Ideas and Hume’s Missing Shade of Blue

This paper provides support for the unorthodox view that Hume’s simple ideas are most fruitfully understood as theoretical posits by showing that adopting this interpretation solves a lingering interpretive difficulty, the missing shade of blue. The missing shade of blue is thought to pose a serious challenge to the legitimacy of Hume’s copy principle (the thesis that all simple ideas are copied from simple impressions). Thinking of Humean simple ideas as theoretical posits reveals a dialectical mismatch between Hume and his envisioned reader that, once understood, makes it clear that the case holds little sway against the copy principle. The solution developed and defended has some significant advantages over extant solutions.

Hume's (Berkeleyan) Language of Representation

Although Hume appeals to the representational features of perceptions in many arguments in the Treatise , his theory of representation has traditionally been regarded as a weak link in his epistemology. In particular, it has proven difficult to reconcile Hume's use of representation as causal derivation and resemblance (the Copy Principle) with his use of representation in the context of impressions and abstract ideas. This paper offers a unified interpretation of representation in Hume that draws on the resources of Berkeley's doctrine of signs. On this account, while the Copy Principle still occupies the core of Hume's content the manner in which any perception represents is understood as involving a relation of sign to thing signified. A sign/signified interpretation has the virtue of allowing Hume to remain within the strictures of his empiricism, while underwriting the various senses in which an impression or idea could possess content. Such an interpretation is not only adequate to account for the role that mental representations play in everyday behavior, but also for the purposes of elaborating the foundations of civil society that are Hume's concern in Book 3 of the Treatise .

Hume's Theory of Mental Representation

Hume's arguments in the Treatise require him to employ not only the copy principle, which explains the intrinsic properties of perceptions, but also a thesis that explains the representational content of a perception. I propose that Hume holds the semantic copy principle, which states that a perception represents that of which it is a copy. Hume employs this thesis in a number of his most important arguments, and his doing so enables him to answer an important objection concerning the status of the copy principle. I further argue that the semantic copy principle is necessary, a priori, and discovered through an analysis of our general idea of representational content.

Hume’s nominalism and the Copy Principle

I consider some ways in which the Copy Principle (CP) and Hume's nominalism impinge on one another, arguing for the following claims. First, Hume's argument against indeterminate ideas isn't cogent even if the CP is accepted. But this does not vindicate Locke: the imagistic conception of ideas, presupposed by the CP, will force Locke to accept something like Hume's view of the way general terms function, the availability of abstract ideas notwithstanding. Second, Hume's discussion of nominalism provides support for the “old Hume” interpretation, that which takes the CP to be a criterion of meaningfulness, as against the “new Hume” reading, according to which it constrains what we can know. Finally, nominalism forces Hume to adopt a more complicated theory of ideas.

Hume’s Argument for the Ontological Independence of Simple Properties

In this paper, I will reconstruct Hume's argument for the ontological (in the sense of rigid existential) independence of simple properties in A Treatise of Human Nature, Book 1 (1739). According to my reconstruction, the main premises of the argument are the real distinctness of every perception of a simple property, Hume's Separability Principle and his Conceivability Principle. In my view, Hume grounds the real distinctness of every perception of a simple property in his atomistic theory of sense perception and his Copy Principle. I will also show why Hume's argument should be seen as relevant nowadays. David Lewis and his followers in metaphysics continue Hume's line of thinking in this respect, which is opposed by power ontologists (Brian Ellis, Stephen Mumford), for example.

Of Liberty and Necessity: The Free Will Debate in Eighteenth-Century British Philosophy (review)

Reviewed by: Of Liberty and Necessity: The Free Will Debate in Eighteenth-Century British Philosophy Benjamin Hill James A. Harris. Of Liberty and Necessity: The Free Will Debate in Eighteenth-Century British Philosophy. Oxford: Clarendon Press, 2005. Pp. xi + 264. Cloth, $99.00. Early modern historians and philosophers interested in human freedom can profitably read this book, which provides a synoptic view of the eighteenth-century British free will debate from Locke through Dugald Stewart. Scholars have not ignored the debate, but as they have tended to focus on canonical figures (Locke, Hume, and Reid), the author’s inclusion of lesser-known yet significant thinkers such as Lord Kames, Jonathan Edwards, and James Beattie is especially welcome. The main thesis of James Harris’s book is that the eighteenth-century British debate was animated by a general commitment to “experimentalism,” i.e., the view that we should be faithful to the data of our experiences of willing. Locke initiated the turn to experimentalism, but in Harris’s judgment it was Hume who first fully adopted it. Of course, Hume’s deflationary moves did nothing to slow the debate, let alone settle it, and necessitarians (Kames, Edwards, Joseph Priestley, and Alexander Crombie) continued to battle libertarians (Beattie, Reid, James Gregory, and Stewart). An equally important theme in the book is the changing fortunes of the contrary notions of moral and physical necessity. In the beginning, only libertarians (Bramhall and Clarke) ascribed moral necessity to the motives underlying human behavior, over the objections of necessitarians (Hobbes and Collins) that physical necessity is the only sort of necessity. Later, however, necessitarians such as Edwards began utilizing the distinction between moral and physical necessity. The book seems to imply a connection between these two themes and the idea that somehow the commitment to experimentalism, which is lacking in the Hobbes-Bramhall and Collins-Clarke debates, pushed necessitarians toward the distinction between moral and physical necessity, but the nature of that connection remains obscure. In any case, the story is fundamentally one of philosophical failure because the commitment to experimentalism provided these thinkers with no leverage against questions about [End Page 646] our freedom. Despite their new orientation, the debate remained stalled because, Harris suggests, there was “profound disagreement about what exactly it meant . . . ‘to introduce the experimental method of reasoning into moral subjects’.” What makes this a good book are its interesting and provocative discussions of Hume and Reid. Harris sees Hume’s treatment as more revolutionary than most, arguing that it rests on a “contentious” understanding of the copy principle that all simple ideas are copies of impressions—it does not follow from my being unable to identify an idea’s aboriginal impression that the resulting idea is incoherent. And regarding Reid, Harris finds parallels between his common-sense commitments to libertarianism and the possibility of knowledge that suggest his critique of the way of ideas is inadequate without a full defense of libertarianism. To have made this a great book, however, Harris should have engaged the secondary literature more and shown why his interpretations are preferable to the alternatives. He clearly knows the literature and has something to say about it, but his comments are buried in footnotes and tend to be passing notices of differences rather efforts to engage the contrary arguments. The biggest flaw, however, is the book’s failure to demonstrate the impact of the rise of experimentalism, a thesis that looks strained when applied to thinkers after Reid. James Gregory, for example, rejects the experimentalist’s “direct appeals to [our] consciousness” of willing for deciding the issue in favor of a priori arguments, and against the necessitarian’s conception of human agency and causation as constant conjunction. So too, Alexander Crombie defends necessitarianism by postulating that many of our motives are unconscious, contrary to Reid’s experimentalist appeals to motiveless activity. Moreover, there are several thinkers, often though not always necessaritarian (e.g., Richard Price and James Oswald in their arguments from moral responsibility), who utilize speculative theses in their analyses of the experience of willing, which makes one wonder about their commitment to experimentalism. Part of the problem is the way Harris focuses on simply laying out...

Two Definitions of ‘cause,’ Newton, and The Significance of the Humean Distinction Between Natural and Philosophical Relations

The main aim of this paper is to explore why it is so important for Hume to defi ne ‘cause’ as he does. This will shed light on the signifi cance of the natural/philosophical relation (hereafter NPR) distinction in the Treatise. Hume's use of the NPR distinction allows him to dismiss on general grounds conceptions of causation at odds with his own. In particular, it allows him to avoid having to engage in detailed re-interpretation of potentially confl icting theories formulated by natural philosophers. Moreover, it provides an instance of the normative nature of Hume's “science of man.” The paper argues that the NPR distinction - in conjunction with the so-called copy principle - is meant to undercut appeals to the authority of theories not founded on Hume's “principles.” In order to illustrate its claims about Hume, this essay explores some aspects of Newton's natural philosophy. Finally, this paper resolves a long-standing interpretive problem: how to reconcile Hume's two “defi nitions” of causation in the Treatise.

Hume's Impression/Idea Distinction

Understanding the distinction between impressions and ideas that Hume draws in the opening paragraphs of his A Treatise on Human Nature is essential for understanding much of Hume's philosophy. This, however, is a task that has been the cause of a good deal of controversy in the literature on Hume. I here argue that the significant philosophical and exegetical issues previous treatments of this distinction (such as the force and vivacity reading and the external-world reading) encounter are extremely problematic. I propose an alternative reading of this distinction as being between original mental entities and copied mental entities. I argue that Hume takes himself to discover this distinction as that which underlies our pre-theoretical sorting of mental entities. Thus, while the Copy Principle is initially treated by Hume as a mere empirical fact, it later comes to play a more substantial explanatory role in his account of human nature. This reading makes Hume's distinction a more philosophically robust one, and avoids many of the exegetical difficulties of previous interpretations.

A Humean Conundrum

Hume's Copy Principle, which accords precedence to impressions over ideas, is restricted to simple perceptions. Yet in all the conceptual analyses Hume conducts by attempting to fit an impression to a (putative) idea, he never checks for simplicity. And this seems to vitiate the analyses: we cannot conclude from the lack of a preceding impression that a putative idea is bogus, unless it is simple. In this paper I criticise several attempts to account for Hume's seemingly cavalier attitude, and offer one of my own.

Reason and Commitment

Don Garrett's strategy, in Cognition and Commitment in Hume's Philosophy, is to reconcile apparent contradictions in Hume's theory. Two examples occur early in Part I of Book I of Treatise. Hume argues that all ideas are derivable impressions (what Garrett calls the Copy Principle). Garrett defends Hume's rigorous attempt to found this principle empirically, taking Hume at his word when he describes it as the first principle I establish in science of human nature. (T 7)1 Notoriously, Hume almost immediately provides a counter-example: suppose a person had experienced all shades of blue except one, and further suppose they were presented with a table of all these shades, with a blank where missing shade ought to be. Clearly, Hume says, such a person could supply from his own relevant idea, without having first experienced corresponding impression. This presents an apparent counter-example to Copy Principle. Another example occurs a little later. Hume claims that Where-ever imagination perceives a difference among ideas, it can easily produce a separation. (T 10) Distinct ideas are separable. Garrett calls this the Separability Principle, and it is almost as important for Hume as Copy Principle. For one thing, it shows that Hume's theory of ideas, though heavily influenced by Locke, is importantly different earlier theory: Locke thought there were some necessary connections between distinct ideas, connections that could not be reduced to identities or partial identities.2 More importantly, separability of distinct ideas is primary ground of Hume's conceivability criterion of demonstration, crucially employed in arguments concerning causation, necessary connection and induction. But Hume seems to present an apparent counter-example to Separability Principle as well. When discussing distinctions of reason, Hume admits that we can distinguish between the

On Garrett's Hume

Hume Studies Volume XXIV, Number 1, April 1998, pp. 131-139 SYMPOSIUM A version of this paper was presented at the symposium on Cognition and Commitment in Hume's Philosophy by Don Garrett, held at the XXIVth International Hume Conference, Monterey, California, July 1997. On Garrett's Hume MARGARET DAULER WILSON Don Garrett's book is impressive for its scholarship; for its friendliness towards Hume (often arguing inventively that rigorous reinterpretation can absolve him from allegations of error or incoherence); and for its emphasis on questions of continuing philosophical worth and interest. As someone who has long found it difficult to enter fully into Hume's system—especially his positions on issues of cognition—I particularly appreciate Don's candid admissions of what one may call (with some pain, in the present context) the serious limitations of Hume's theories in this area. Despite such concessions , of course, Garrett still holds that Hume's achievements in the Treatise and later works continue to reward philosophical study and critical involvement. And he makes clear through detailed analysis the force of Hume's critique of principles central to the positions of major Rationalist philosophers—which indeed may seem often "dogmatic." In the area of cognitive theory specifically, and closely related treatments of such "metaphysical " topics as causality and substance, Garrett explains Hume's systematic opposition to intellectualist doctrines espoused by Descartes and such successors as Spinoza and Leibniz. As Don emphasizes, Hume followed in the steps of Locke and Berkeley in rejecting the Cartesian conception of intellect; but his opposition to this supposed "faculty" was in many ways more systematic and searching than theirs. But, after all, Hume was working in a later period; and yet (I would be inclined to argue) he intensified (rather than overcame) certain central problems in previous empiricist accounts of human mentality. The late Margaret Dauler Wilson (1939-1998) was Stuart Professor of Philosophy at Princeton University, Princeton NJ USA. 132 Margaret Dauler Wilson I'll try to give some color to this perhaps "««friendly" suggestion mainly by sketching out some doubts about Garrett's positive claims about epistemological support for the "Copy Principle"—a principle which, as he says, is fundamental to Hume's philosophy, and derives in large degree from Locke. I'll also raise a couple of questions about Hume's imagist conception of "abstract ideas," derived from Berkeley. Garrett makes some interesting appeals to this conception in arguing that apparent conflicts or incoherences in Hume's position can be resolved, if its pivotal role is recognized. But the conception, as he explains it, seems to present sufficient difficulties of its own that one may well wonder whether its pivotal role (assuming Garrett's interpretations are right) is such a good thing. I'll conclude with some minor queries about certain of Garrett's early remarks about pre-Humean rationalist philosophers. I. As explained by Garrett, the Copy Principle encompasses the claims that every simple "idea" (1) has an exactly resembling simple impression (sensory experience); and (2) is at least partly caused by a simple impression —presumably, the very one that it exactly resembles (CCHP 41).x (Additionally—in the Treatise anyway—Hume holds that every simple impression has a "corresponding" [and I think Don takes this to mean exactly resembling] idea—which is just a fainter copy of itself [CCHP 44]). Critics (most emphatically Antony Flew) have claimed that Hume presents this principle as if it were an empirically-supported psychological law; but then "outrageously" wields it in a normative way to rule out the very existence of "ideas" that might be presented as counterexamples to it. In other words, the "counterexamples" are not even entertained as empirical counter-evidence, but rather doctrinairely ruled out as if inconsistent with a known a priori, necessary truth. Garrett, however, maintains that Hume consistently presents the principle as an empirically grounded, contingent claim. He writes that "[t]he Copy Principle...is a relatively straightforward empirical claim that the presented content of those mental representations that are less 'lively' than (Humean) impressions is copied from the experienced content of these impressions." He stresses that Hume does seriously entertain possible counterexamples —notably the famous "missing shade of blue...

A copy network with shared buffers for large-scale multicast ATM switching

An architecture for the copy network that is an integral part of multicast ATM switches is described. The architecture makes use of the property that the broadcast banyan network (BBN) is nonblocking if the active inputs are cyclically concentrated and the outputs are monotone. In the architecture, by employing a token ring reservation scheme, the outputs of the copy network are reserved before a multicast cell is replicated. By the copy principle, the number of copies requested by a multicast call is not limited by the size of the copy network so that very large multicast switches can be configured in a modular fashion. The sequence of cells is preserved in the structure. Though physically separated, buffers within the copy network are completely shared, so that the throughput can reach 100%, and the cell delay and the cell loss probability can be made to be very small. The cell delay is estimated analytically and by computer simulation, and the results of both are found to agree with each other. The relationship between the cell loss probability under various traffic parameters and buffer sizes is studied by computer simulation. >