René Descartes is famous for distinguishing between “the moral mode of knowing which suffices for the regulation of life,” and “that Metaphysical mode of knowing,” which is beyond all rational doubt. The kind of knowledge that suffices for practical affairs is of little concern to Descartes's philosopher, who seeks knowledge that can be grasped with absolute certainty. Although the ideal of Cartesian certainty largely has been abandoned, many philosophers retain a two-tiered conception of knowledge: According to this conception, the knowledge pertaining to the “practical needs of life” is, at best, a kind of second-class truth that must either be validated by science or relegated to the dustbin of the merely heuristic.

Among philosophers who take “all traits of reality worthy of the name” to be exclusively in the hands of the sciences or, more generally, in the hands of a metaphysics that aspires to be scientific, there is disagreement about the extent of scientific knowledge: Are the physical sciences the only source of genuine knowledge, as Quine holds, or should sciences that appeal to generalizations not translatable into the austere notation of theoretical physics also be recognized as sources of first-class truth, as so-called nonreductive materialists hold? Either way, according to the received two-tiered view, putative truths that resist integration into scientific theory must be understood “with a grain of salt.” As Wilfrid Sellars put the received view so vividly, “In the dimension of describing and explaining the world, science is the measure of all things, of what is that it is, and of what is not that it is not.”

The Standard View seems to many to be so obviously correct that mere criticism may not dislodge it. Although I argue in Part I that both eliminativist and noneliminativist versions of the Standard View are beset with difficulties, I want to push farther. In Part II, I want to undercut a central motivation for the Standard View, namely, that the role of beliefs in causal explanation requires that beliefs be brain states. As is pointed out in Chapter 2, noneliminativists typically are concerned to vindicate the causal-explanatory role of belief. Even eliminativists, who deny that there are any beliefs at all, agree that belief explanations purport (albeit wrongly, they contend) to be causal explanations. If we rule out appeal to “immaterial” causes, it may seem that if beliefs have a causal-explanatory role in behavior, then they must of necessity be physically realized internal states of believers – in short, they must be brain states.

This claim – that the causal explanatoriness of belief requires that beliefs be brain states – and, with it, the motivation for the Standard View rest on a hopelessly anemic conception of causal explanation. In this chapter, I want to expose the shortcomings of the conception of causal explanation that underlies the claim. Why does the claim seem plausible? The answer, I think, is that philosophers impose certain constraints on causally explanatory properties.

There are both defensive and constructive reasons to try to extend my account of deliberation of ends to explicitly interpersonal contexts. To begin with the obvious positive reasons, the nature of interpersonal deliberation is of interest in its own right, both philosophically and practically. Much actual deliberation is interpersonal. Even when a single individual is deciding what to do with his or her life, he or she may seek advice from others and deliberate with them about some personal choice. More strictly interpersonal are the discussions within groups and institutions of various kinds about what that body will do. As a practical matter, we would like to know to what extent the theory of individual deliberation developed in the last chapters can apply to the setting of ends in these interpersonal settings. Whether the general account of rational deliberation of ends I have developed can extend to interpersonal settings is not the same question as whether it can be objective. Philosophically, however, interpersonal deliberation is of interest not only because of the structural problems posed by interpersonal settings, but also because as we try to extend the theory of individual deliberation to the interpersonal setting, additional scope for objectivity will enter. I do not mean to imply that intersubjectivity is equivalent to objectivity; but if there is some correlation between the two, then the attempt to work out an intersubjectively acceptable understanding of final ends would require attaining a greater degree of objectivity than does an individual's deliberation of ends.

We have just arrived at the importance of building coherence among norms via considerations about how we may rationally settle conflicts among our norms. Yet the necessity of invoking some sort of coherence standard has been implicit in my argument ever since Chapter II, where I argued that practical reasoning should not be either reduced to deductive reasoning or assimilated to any pattern of necessary validity. These contrasting routes to a coherence account merge smoothly. The last section's argument suggests that our systems of norms are not and should not be pyramidally arrayed, with all value or warrant flowing from one or a few self-evident or self-presenting starting points at the peak. If there are starting points of this status, they are likely to be specific, scattered, and spread throughout our normative commitments. The question then arises how one can gather this dispersed warrant in support of a practical theory. Complementing this bidirectionality, Chapter II's argument implies that even if there were a few central starting points, practical reasoning could not flow of necessity from them alone. Instead, the nondeductive moves that are made from a norm to a conclusion can gain support from other norms in the system. To lay out this support is to build coherence among one's norms. This schematic answer about how to justify nondeductive moves, it will be noted, is also an answer to how to gather dispersed warrant, namely by connecting one's norms into a practical theory of sorts.

STATEMENT AND DEFENSE OF OUR PROJECT

One of the main projects in this book is to conduct a conceptual investigation of the notion of an individual substance as ordinarily understood, paradigm instances of which seem to be particular material objects and persons. In one of its ordinary senses, the term ‘thing’ means individual substance. For example, the term ‘thing’ is being used in this sense in the following sentences:

The task of this chapter is to show via examples how rational deliberation can embrace the dialectical specification and adoption of an ultimate end. Such realism as I can provide will be important, for an additional source of skepticism about deliberation extending to ultimate ends, beyond those mentioned in §28, is pragmatic rather than principled. It holds, not that the normative force of practical reasoning depends upon taking the ultimate end to be nondeliberable, but that people do not bother to extend their deliberation to the level of the ultimate end, which it views as a philosopher's abstract invention rather than a feature of ordinary deliberations. While philosophers may reason about ultimate ends, and while their reasoning may be subject to holistic checks, this does not mean that we can deliberate about ultimate ends. To counter this debunking form of doubt, I need to show how specification of an ultimate end can indeed enter into an individual's deliberation about what to do. Although this effort leads me into some fairly lengthy exercises at writing fiction, in some respects they remain not nearly detailed enough. In neither of my examples will I be able to do more than merely suggest the groping search for equilibrium that would characterize actual deliberations. By and large, all I can do is to trace out a realistic trajectory of deliberation's conclusions.

VIRTUOUS DELIBERATORS

Since my examples of deliberation that extends to ultimate ends involve deliberators who begin with roughly Aristotelian or liberal commitments, I must confront the suspicion of circularity that this raises.

WHAT IS A COLLECTIONIST THEORY OF SUBSTANCE?

A distinction needs to be drawn between two sorts of collectionist theories about substance. The eliminative collectionist theory holds that there are no substances. Instead, there are collections of entities of another sort, which collections are not to be identified with substances. This view usually maintains that what are taken to be substances are really collections of nonsubstances. A proponent of this view seems to be the Hume of the Treatise. Hume is the sort of eliminationist who thinks that there is no intelligible concept of substance, but it is possible to be an eliminationist and also hold that the concept of substance is a coherent one.

A second kind of collectionist theory identifies substances with collections of nonsubstances. Such a theory attempts to provide a philosophical analysis of the concept of an individual substance as ordinarily understood in terms of a collection of this kind.

THE NATURE OF A SOUL

In previous chapters, we have explored the intuitive notion of an individual substance, culminating in our analyses of this notion in Chapter 4.

The aim of avoiding value conflicts (on which more in Chapter VII) provides a strong motivation to systematize and unify our practical and moral concerns. The task for the current chapter is to show that despite this, there is no need for this systematization to take the form of unification around a single commensurating standard. More generally, I will argue that rational choice even within a limited domain does not require a partial commensurability that applies to that domain. By “commensurability,” as applied to values or goods, I will henceforth generally have in mind the sort of deliberative commensurability defined in §16. I will argue that such commensurability is not necessary even if systematization is. In the present chapter I will simply diagnose the narrow-mindedness that leads many to think that commensurating is the only rational way to systematize. It will be the task of Chapters VII–X to develop the alternative mode of systematizing.

THE ARGUMENT THAT COMMENSURABILITY IS A PREREQUISITE OF RATIONAL CHOICE

Suppose, to adapt one of Kant's examples, that you have to decide between continuing to listen to an enlightening philosophy lecture and departing to join your family for dinner (Kant 1956, I.I.i.3, Ak. 23). Can you arrive at your decision rationally without finding a way to commensurate the values involved? It seems to be widely assumed, both among philosophers and popularly, that you cannot.

One way to try to make sense of deep disagreement would be to analyze it as resting (also) upon conceptual incommensurability of some kind. Yet as one presses toward complete conceptual incommensurability, it is difficult to hold on to the depth of disagreement that one was trying to explain in the first place. While some will not be surprised that after trying to plumb the murky depths one comes up empty-handed, we will all learn from understanding more explicitly why this is so and how it may be squared with the apparent phenomena of deep disagreement. Accordingly, in the next section I will describe how one gets lost in the alleged depths of disagreement. Section 39 will turn to underlying difficulties with “the very idea” of a framework or “conceptual scheme,” in terms of which conceptual incommensurability is defined. This will pave the way for a less conceptually ambitious but more enduring recasting of the notion of conceptual distance, which will be set out in §40.

THE ELUSIVENESS OF DEPTH

In elaborating the idea of conceptual incommensurability, I cannot pretend simply to be uncovering the idea that unites all of the diverse cases of deep disagreement. Instead, let me simply put forward an initial definition of it intended to capture those aspects of the phenomena that particularly pose a problem for my theory of rational deliberation of ends.

TWO ARISTOTELEAN THEORIES

As we have indicated, the concept of substance has played a prominent role in the history of philosophy. Any attempt to provide an analysis of substance should be informed by an awareness of the efforts of the great philosophers of the past to characterize the ordinary concept of substance, and of the strengths and weaknesses of those efforts. As will become evident, our own analysis of the ordinary concept of substance is rooted firmly in one of the traditional approaches to understanding this concept. In this chapter, we will survey and critically assess several historically important attempts to analyze the ordinary concept of individual substance.

The first historically important attempt to analyze the ordinary concept is due to Aristotle, and states that a substance is that which can persist through change.

This essay is an exploration of the ontological landscape of ordinary discourse and thought. Most philosophers would concede that there is an ordinary, commonsense, or “folk” conceptual scheme, and that this scheme has certain ontological presuppositions. Foremost among these is the idea that there are enduring things, or individual substances, continuants such as people, rocks, flowers, and houses. Other kinds of entities which common sense appears to recognize are events, places, times, properties, and collections, as well as surfaces, edges, shadows, and holes. Any ontologist must begin as a point of reference with a consideration of this folk or commonsense ontology, even if in the end he revises it in some way. At least since the time of Aristotle, philosophers have tried to organize and relate entities of the kinds which belong to the commonsense ontology, kinds which Aristotle called categories.

One of our primary aims is to analyze the ordinary or commonsense concept of an individual substance, and the other is to characterize the possible extension of this concept. These analytical enterprises do not involve any commitment to the existence of an individual substance so conceived. Our analysis of substance will be carried out in terms of a broad theory of ontological categories which covers both commonsense categories of the sort just referred to and categories of a more theoretical sort, which are scientific, mathematical, or philosophical in origin.

We have maintained that point-positions and instants are not parts of space and time, respectively. Rather, we have taken the neo-Aristotelean view that such entities are dependent on places and times of higher dimensionality. Thus, we said that a point-position can be a limit of a line, or the place of a corner of a material object, or a place where two spheres touch, and so forth, but a point-position cannot exist apart from a place of higher than zero-dimensionality. Thus, our view has been an antifoundationalist one when it comes to space and time, one aspect of this antifoundationalism being that space and time are not composed of unextended parts.

However, many philosophers, taking their lead from certain mathematicians and, we believe, from the logicist tradition, hold that extended spaces and temporal intervals have a nondenumerable number of zero-dimensional parts. M. J. White has aptly described the contrast between the two views in question: