The Concept of Identity
Hirsch (Eli)
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  1. My main concern in this book is identity through time, first with respect to ordinary bodies, then underlying matter, and eventually persons. These issues link up at various points with other aspects of identity, such as the spatial unity1 of things, the unity2 of kinds, and the unity3 of groups. One of my concerns is to understand how our identity concept ordinarily operates in these various respects; but I also try to understand, especially in later chapters of the book, why this concept is so central to our thinking, and whether we can justify seeing the world in terms of such a concept.
  2. Part One, with a few minor differences (mainly in footnotes), was published several years ago as a monograph on the persistence of objects. That work, though its circulation was quite limited, did generate some interest, and this has encouraged me to present it again in a more accessible form. The views expressed in Part One are augmented, and in certain respects qualified, by the treatment in Part Two of various related themes of identity. Though both parts of this book may be said to form a single extended discussion, the chapters in Part Two can also be read as relatively self-contained essays, which is in fact the spirit in which they were written.
  3. Acknowledgements to Munitz, Chisholm, Kripke, Shoemaker, etc.
      Introduction to Part One – 3
    1. Continuity – 7
    2. Sortals4 – 34
    3. The Basic Idea of Persistence – 72
    4. The Persistence of Matter – 113
    5. The Metaphysics of Persistence – 138
      Introduction to Part Two 177
    1. Foundations of Identity – 181
    2. Matter, Causality5, and Stereotypes of Identity – 211
    3. A Sense of Unity6 – 236
    4. Natural Kinds7 and Natural Units – 264
    5. Constraints on Self-Identity – 286


Oxford University Press, 1982

"Hirsch (Eli) - The Persistence of Objects: Introduction"

Source: Hirsch - The Concept of Identity, 1982, Introduction to Part 1

Full Text
  1. Our concept of a physical object's persistence through time seems so fundamental and primitive that it requires a special effort to appreciate what philosophers might be after when they ask for an analysis of this concept. Traditionally the request for such an analysis might take the form of such questions as;
    → What does the identity through time of a physical object consist in?
    → What is it for a physical object which exists at one time to be the same object as a physical object which exists at another time?
    In more recent literature one typically finds philosophers asking for an account of our "identity criteria1" for objects. This new terminology, at least as I intend to employ it, still expresses very much the same traditional request for an analysis of our identity concept, except perhaps that to talk about "identity criteria2" is to signal more clearly one's quite reasonable willingness to settle for an analysis which may be less than airtight and which may allow for many borderline cases3.
  2. When we ask with regard to physical objects what their identity through time consists in, we are asking for an account of the unity4 of a physical object's career. Any physical object has a career which stretches over a period of time, a career which we can think of as comprised of a temporal succession of momentary stages. The successive parts, or stages, of an object's career must hang together in some distinctive way; otherwise there would be nothing to prevent us from arbitrarily combining into a single career the early stages of one object with the later stages of a different object. Evidently not just any succession of object-stages corresponds to a single persisting object; some do and some do not. So in order for object-stages to add up to a single persisting object they must be related in some special way. What I am seeking in Part One is an analysis or definition of what that relationship is.
  3. In a sense, of course, any succession of object-stages, however arbitrary, does add up to something: perhaps to an event, or to a state of affairs or, if nothing else, at least to a "merely arbitrary succession of object-stages." What is important, however, is that not every succession adds up to a persisting object or body (I will use these expressions interchangeably), where this fundamental category is to be understood as loosely comprising items which can straightforwardly be said to occupy space and to persist through time. Clearly only certain privileged successions are accorded the special status of uniting into a single persisting object in this sense, which gives rise to the question as to what the unity-making5 relationship is in virtue of which some successions enjoy this special status.
  4. Our question, I want to stress, is primarily conceptual rather than epistemological. We are not, that is, to be thinking primarily of a situation in which someone has not seen an object for some time and a question arises as to how he can know that he has really come across the same object again. Rather we are to be thinking primarily of a situation in which someone continuously observes an object for a stretch of time, and, as I shall often put it, traces the object's career for that period. Our question is what criteria of identity6 enter into this tracing operation. How can we analyze what it means to judge in those optimal circumstances that it was a single persisting object that was being followed?
  5. It must be emphasized, furthermore, that this is a question about our most ordinary notion of physical persistence. We want an account of what goes into our thought about the identity through time of tables, trees, and other objects that we ordinarily talk about. A philosopher may of course hold that the ordinary notion of physical persistence is not ultimately important, perhaps because ordinary physical objects are not among the "ultimate constituents of reality." Whatever might be the cogency of this sort of claim (and I shall have something to say about it in the course of what follows), the fact remains that we certainly do have an ordinary way of thinking about the physical world, and it must be of some philosophical interest to provide an analysis of that way of thinking.
  6. Our question, then, is about as clear as the notion of giving an "analysis" (or a "definition"), which means, I think, that it is not luminously clear at all. One important difficulty with this notion has to do with deciding when an analysis is "circular,'" when, that is, the concepts in terms of which it is couched depend, in some sense, on the concept being analyzed. This difficulty may seem potentially devastating when the concept to be analyzed is as fundamental to our overall thought as the concept of physical persistence. But perhaps we may provisionally adopt a fairly tolerant attitude about this. If we can provide an account of our identity criteria7 which strikes us as at least not patently circular then we may feel that we have the kind of analytic illumination that we sought. It may turn out, of course, that granted even a reasonable measure of tolerance our concept of physical persistence, or some application of that concept, will seem to resist the sort of analysis that we are seeking. In this case we will have to say that the concept, or some application of it, is, in some important sense, ultimate and unanalyzable. Later, in Chapter 4 ("Hirsch (Eli) - The Persistence of Matter"), I will in fact defend the position that our concept of the persistence of material substance is in a sense unanalyzable. And in Chapter 5 ("Hirsch (Eli) - The Metaphysics of Persistence"), the final chapter of this part, I will consider a bit more forthrightly some of the metaphysical issues that may revolve around the idea of giving an analysis of physical persistence. These issues in their full generality, however, will not be dealt with until Part Two8.
  7. The topic that I intend to focus upon in this first part is rather severely circumscribed. I want to examine our concept of persistence as it pertains to the seemingly most central and unexceptionable instances of physical objects or bodies. These would include, I assume, such things as tables and cars, mountains and stones, trees and flowers, cats and dogs, chunks of clay and bits of wood. But I shall have nothing to say in this part about the identity conditions for such nonsubstantial items as events and properties, or such corporate items as groups and forests; nor will I enter into the very special problems which seem to affect our concept of the persistence of persons9. Some of these additional issues will be discussed in Part Two.
  8. An object's unity10 through time is by no means the only philosophically challenging mode of object-unity11. In particular one can raise questions about an object's unity12 through space which parallel in many ways questions about its unity13 through time. The spatial question would have to do with our basis for treating some, but not all, aggregates of matter as unitary objects. This question will eventually be addressed in Chapter 3 ("Hirsch (Eli) - The Basic Idea of Persistence"). But in order to focus properly on the immediate question, a question essentially about identity through time, the perspective to adopt is one in which an aggregate of matter has (on whatever basis) already been delineated as a unitary object and our primary concern is to understand what it means to trace that object's career through time.

In-Page Footnotes ("Hirsch (Eli) - The Persistence of Objects: Introduction")

Footnote 3: On the meaning of "identity criteria" see Footnote 8: See "Hirsch (Eli) - Minds and Bodies: Introduction", and the following Chapters.

"Hirsch (Eli) - Continuity"

Source: Hirsch - The Concept of Identity, 1982, Chapter 1

  1. The Simple Continuity Analysis – 7
  2. Qualitative Continuity – 10
  3. Spatiotemporal Continuity – 15
  4. Is Continuity Necessary? – 22
  5. Is Continuity Sufficient? – 25

"Hirsch (Eli) - Sortals"

Source: Hirsch - The Concept of Identity, 1982, Chapter 2

  1. The Sortal1 Rule – 34
  2. The Making of a Sortal2 – 40
  3. Coming into Existence and Going out of Existence – 47
  4. Identity, Predication, and Constitution – 57
  5. The Compositional Criterion – 64

"Hirsch (Eli) - The Basic Idea of Persistence"

Source: Hirsch - The Concept of Identity, 1982, Chapter 3

  1. A Question about Sortal-Relativity1 – 72
  2. The Basic Rule – 77
  3. Limitations of the Basic Rule – 82
  4. Refining the Basic Rule – 90
  5. Unity2 through Time and Space – 97
  6. Articulation – 105

"Hirsch (Eli) - The Persistence of Matter"

Source: Hirsch - The Concept of Identity, 1982, Chapter 4

  1. A Puzzle about Matter – 113
  2. An "Ultimate" Kind of Persistence – 119
  3. Searching for Identity Criteria1 – 123
  4. Matter and Common Sense – 128

"Hirsch (Eli) - The Metaphysics of Persistence"

Source: Hirsch - The Concept of Identity, 1982, Chapter 5

  1. Do We Need Persisting Objects? – 138
  2. A Question about Spatiotemporal Continuity – 144
  3. Identity Schemes – 149
  4. "Real" and "Fictitious" Persistence – 156
  5. Can We Justify Our Identity Scheme? – 162

"Hirsch (Eli) - Minds and Bodies: Introduction"

Source: Hirsch - The Concept of Identity, 1982, Introduction to Part 2

Full Text
  1. This part attempts, first, to clarify and defend some of the views already presented, and, second, to open up some additional questions about the nature of identity. Each chapter is designed to be an essentially self-complete essay, though there is inevitably a considerable amount of cross-reference.
  2. The first two chapters deal directly with several objections to the previous views. Chapter 6 ("Hirsch (Eli) - Foundations of Identity") addresses in detail the crucial objection that an analysis of our concept of bodily identity is necessarily circular because the concept is more fundamental, both metaphysically and epistemologically, than any concepts in terms of which the analysis might be couched. In Chapter 7 ("Hirsch (Eli) - Matter, Causality, and Stereotypes of Identity") I take up Shoemaker's suggestion that causal connectedness1 is necessary for identity, and the radical suggestion that there are no logically sufficient criteria of identity2. Here I also show how Putnam's notion of a stereotype might be applied to an analysis of identity.
  3. Several times in Part One3, I expressed the conjecture that our concept of bodily identity is innately determined. This is elaborated and defended in Chapter 8 ("Hirsch (Eli) - A Sense of Unity"). The question of innateness leads to a consideration of the essential connection between the issue of "unity4" and the issue of "similarity," a connection which is pursued in Chapter 9 ("Hirsch (Eli) - Natural Kinds and Natural Units"). The notion of a natural kind5 is prominent in recent literature, and in the latter chapter I explore various points of connection between that notion and what I call a "natural unit."
  4. The topic of personal identity, which I studiously avoided in Part One, is now addressed in Chapter 10 ("Hirsch (Eli) - Constraints on Self-Identity"). This chapter extends various issues of relativism, conventionalism, and innatism into the realm of personal identity. In this discussion I adopt the rather extreme device of assessing at length an utterly alien conception of personal identity; the device will not, I hope, overly tax the reader's indulgence for the philosophy of the weird.
  5. Running through a number of these discussions is my preoccupation with the issue already broached in Chapter 5 ("Hirsch (Eli) - The Metaphysics of Persistence") of what the status is of our ordinary identity concept. There I considered the claim that:
    → There are compelling reasons for us to describe the world in terms of ordinary objects.
    And now in Chapter 6 ("Hirsch (Eli) - Foundations of Identity") I go on to consider the claim that;
    → Ordinary objects are basic,
    and in Chapter 9 ("Hirsch (Eli) - Natural Kinds and Natural Units") the claim that:
    → Ordinary objects are natural units.
    These are three ways of conferring upon ordinary objects a special and exalted status.
  6. The three status claims are evidently not unrelated, but they do carry rather different philosophical associations. The first claim suggests that we could cite some ordinary reasons in support of our identity concept, theoretical or practical reasons akin to those – e.g., of probability or efficiency – which we ordinarily give in support of a belief or practice. I have already criticized this position, and will argue against it again in somewhat different contexts in Chapters 8 ("Hirsch (Eli) - A Sense of Unity") and 10 ("Hirsch (Eli) - Constraints on Self-Identity").
  7. The claim that ordinary objects are "basic" can be taken in two senses.
    1. From a metaphysical standpoint the claim suggests that the ordinary concept of an object cannot be analyzed or defined in terms which do not already presuppose the concept.
    2. From an epistemological standpoint the claim suggests that our knowledge of the world depends on our knowledge of ordinary objects.
    The metaphysical claim does not seem to me convincing: some of the central issues here have partially emerged in Chapter 5 ("Hirsch (Eli) - The Metaphysics of Persistence"), and will be clarified and developed in Chapter 6 ("Hirsch (Eli) - Foundations of Identity").
    As regards the epistemological claim it is necessary to distinguish between two questions.
    1. We can compare the status of an ordinary object to the status of the momentary stages of an object; or
    2. We can compare the status of an ordinary object to the status of other successions of stages, successions, that is, which do not correspond to what we ordinarily conceive of as persisting objects.
    Whereas I will suggest in Chapter 6 ("Hirsch (Eli) - Foundations of Identity") that the stages may be epistemologically more basic than the objects, I would certainly hold that the objects are epistemologically more basic than other successions; obviously this is so if, as I think, our minds are innately determined to synthesize the stages into ordinary objects. Note that from the metaphysical standpoint this distinction between the two comparisons seems inconsequential: ordinary objects, it seems, are more basic metaphysically than the other successions if and only if they are more basic metaphysically than the stages.
  8. What is suggested by the claim that ordinary objects are "natural units"? When philosophers talk about "natural kinds" they seem to imply that there is an objective distinction, apart from our human attitudes and practices, between kinds and artificial constructions. The analogous claim with respect to objects is that there is an objective distinction between ordinary persisting objects and other successions of stages, a distinction that can be drawn without reference to our attitudes or practices. But that claim seems almost trivially correct; and certainly it does not confer any special status on the objects. That ordinary objects are objectively distinguishable from the other successions surely does not exalt the objects above the other successions. The objects are, I think, exalted and "natural" only in the psychological sense that it is natural for us to conceive of the world in terms of such objects. If it is held that there is an objective distinction between natural kinds6 and artificial classes – a position which (as I explain in Chapter 9 ("Hirsch (Eli) - Natural Kinds and Natural Units")) is denied by certain nominalists – then it may perhaps also seem plausible to regard the natural kinds7 as metaphysically basic, as presupposed in any adequate conception of the world. But this connection between "naturalness" and "metaphysical basicness" is, I shall maintain, not plausible for "natural units." Though there is an objective enough distinction between the natural units – i.e., the ordinary objects – and other successions, the special status of the ordinary objects seems to be essentially subjective, essentially a function of how we think.
  9. And it is not just physical things that seem to lack an objectively or metaphysically exalted status but persons too; or so I argue in Chapter 10 ("Hirsch (Eli) - Constraints on Self-Identity"). But here especially the psychological centrality of our concept of identity seems strikingly evident. One aspect of my view, then, is that our concept of identity, in its application both to bodies and to persons, suffers from a certain kind of metaphysical arbitrariness. That theme has already been sounded at the end of Part One, and will be amplified in this Part. But in the ensuing chapters I want also to lay stress on the correlative point that our concept of identity is psychologically not arbitrary at all; there are probably deep psychological constraints which determine that just this concept should structure our understanding and knowledge. If our identity concept disappoints us as metaphysicians, it may yet fulfill our expectations as philosophical psychologists and epistemologists.

In-Page Footnotes ("Hirsch (Eli) - Minds and Bodies: Introduction")

Footnote 3: See "Hirsch (Eli) - The Persistence of Objects: Introduction" and the following Chapters.

"Hirsch (Eli) - Foundations of Identity"

Source: Hirsch - The Concept of Identity, 1982, Chapter 6

  1. Metaphysical Priorities and Epistemological Priorities – 182
  2. Body-Stages – 184
  3. Temporal Parts – 188
  4. A Question of Priorities – 192
  5. Spatiotemporal Continuity – 196
  6. Analyzing Bodily Identity – 201
  7. Epistemological Priorities – 202

"Hirsch (Eli) - Matter, Causality, and Stereotypes of Identity"

Source: Hirsch - The Concept of Identity, 1982, Chapter 7

  1. Optimal Cases – 211
  2. Compositional and Causal Continuity – 216
  3. Stereotypes of Identity – 227

"Hirsch (Eli) - A Sense of Unity"

Source: Hirsch - The Concept of Identity, 1982, Chapter 8

Philosophers Index Abstract
  1. The author maintains that our most basic criteria of bodily unity1 are innately determined.
  2. Two other positions are considered and rejected.
    1. The 'empiricist' would hold that our criteria of unity2 are derived from previous learning.
    2. The 'conventionalist' would hold that these criteria are arbitrary conventions of language.
  3. The empiricist position is rejected on the grounds that there is no inference that could yield our criteria of unity3.
  4. The conventionalist position is rejected on the basis of empirical evidence that infants experience unity4 in an essentially normal way before acquiring language.

  1. Criteria of Unity5 – 236
  2. Unity6 and Similarity7 – 239
  3. Conventionalism – 244
  4. An "Empiricist" Explanation – 249
  5. Focusing on Objects – 255
  6. Conclusion – 262

"Hirsch (Eli) - Natural Kinds and Natural Units"

Source: Hirsch - The Concept of Identity, 1982, Chapter 9

  1. Kinds and Units – 264
  2. Kinds and Similarity1 Classes – 267
  3. Is the Class of Units a Kind? – 270
  4. Kinds and Individuation2 – 274
  5. The Basis of Kinds and Units – 278

"Hirsch (Eli) - Constraints on Self-Identity"

Source: Hirsch - The Concept of Identity, 1982, Chapter 10

  1. A Strange Identity Concept – 287
  2. Metaphysical Constraints – 293
  3. Pragmatic Constraints – 297
  4. Psychological Constraints – 301
  5. The Sense of Self – 307

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