The Journal of Value Inquiry 25: 81-87, 1991. �9 1991 Kluwer Academic Publishers. Printed in the Netherlands.

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The Principle of Relevant Similarity*

GARY W. LEVVIS Department of Philosophy, The University of Tennessee at Knoxville, Knoxville, TN 37996-0480

In "Why We Do Not Have to ~I)~eat Like Cases Alike ''1 Michael Lavin argues that the Principle of Relevant Similarity is false. This principle, which plays a prominent role in ethical and legal reasoning, may be stated in the following way:

If x and y are relevantly similar, then the same moral judgments apply to x as to y and vice versa. (p. 313)

Suppose, for example, that I a m x and y is my next-door neighbor and that the homes we own are connected to the municipal sewer line. If I am entitled to use the sewer line, and if my neigbor is similar to me in relevant ways (suppose that the relevant similarity in this context is that we are both homeowners and taxpayers and that our respective families put roughly the same strain on the system), then if the Principle of Relevant Similarity is true, we ought to infer that my neighbor is entitled to use the sewer line as well. Now, we might think it is possible to replace moral arguments which appeal to this meta-ethical principle with a similar form of argumentation in which we employ a moral rule that is applicable to both x and y. For example, wouldn't it be simpler (and more effective) to argue before a magistrate that all homeowners who pay their taxes are entitled to use the sewer line, y is a homeowner who pays her taxes, and, therefore, she is entitled to use the sewer line? We might criticize those who treat the Principle of Relevant Similarity as an adequate desideratum in moral matters on the grounds that appealing to a general moral principle is always preferable to appealing to an analogy; after all, when faced with such an analogy can we not ask why the similarities between x and y are relevant? Don't we require something in the nature of a moral principle in order to answer this question? Indeed, wouldn't our capability to even specify the

* I would like to thank Meg Levvis, Michael Lavin, and Robert Ginsberg for their helpful suggestions concerning this essay.

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relevant similarity between x and y presuppose knowledge of some such principle? But those who advocate the Principle of Relevant Similarity in moral debate might object that while it may be preferable to appeal to a general moral principle when possible, this is not possible all the time. There may be occasions when no moral principle is available, or there may be occasions when a moral principle seems available but no way exists to determine whether x or y fall within the relevant categories. For example, I might accept the general moral principle that killing persons is wrong, but because I lack identity conditions for persons, I may not be able to deter- mine whether my crazy uncle Mortimer should be considered a person or not. How else but by noting similarities and differences between Mortimer and other individuals who I regard as typical persons could I determine which conclusion to draw? I may not know what about such individuals makes them persons, but I might know that they are persons, and I might be able to know when other individuals are enough like them to warrant their treatment as persons too. In such cases the Principle of Relevant Similarity appears unavoidable. 2 Lavin, however, thinks that the principle of Relevant Similarity is false and so should never play a role in the formation or justification of moral judgments. In the remainder of tliis essay I argue that Lavin is mistaken and that the Principle of Relevant Similarity is immune to counter-example.

Lavin presents two cases in support of his claim that the Principle of Relevant Similarity is false. Before turning to these cases, however, let us get quite clear on what is required of any suitable counter-example. Such a counter-example must satisfy four conditions. Condition (I) is that some entity x must exist with respect to which we would be willing to form a moral judgment. Condition (II) is that some other entity y must exist which we would be willing to regard as a relevantly similar to x. If there is any morally relevant dissimilarity between x and y, then Condition (II) cannot be considered satisfied. Condition (III), obviously enough, is that in spite of (I) and (II) being satisfied we would not be willing to form the same judgement regarding y as we are of x. The fourth condition is less apparent than the first three. Condition (IV) is that there must not be some general moral principle effectively decidable for x and y in virtue of which we would form a particular judgment of x but not of y. This condition is entailed by the others and functions as a constraint upon Condition (II). If x and y are deemed relevantly similar by virtue of the fact that some moral principle exists under which they may both be subsumed, then it will be impossible for Conditions (I) and (III) to be simultaneously satisfied. If, on the other hand, a moral principle exists under which one but not the other may be subsumed, so that Conditions (I) and (IID are met, then for Condi- tion (II) to be satisfied is impossible; x and y would fail to be relevantly

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similar with respect to their moral properties. So, Conditions (I)-(III) can be simultaneously satisfied, only if Condition (IV) likewise holds. This last condition is consistent with the idea that the Principle of Relevant Similarity primarily fulfills a function in contexts for which no effectively decidable moral principle exists. Since advocates of the Principle of Relevant Similarity might concede that under some circumstances a better way may exist to justify our moral beliefs than by appealing to relevant similarity, observance of Condition (IV) functions as a safeguard against attacks upon this sort of straw man.

Turning now to Lavin's two counter-examples, I first consider his second and less developed case. We are asked to imagine the kinds of preferential treatment we typically afford the members of our family:

[M]uch favoritism is morally easy to justify. I help my nephew more than I help a stranger's son because I love my nephew. And that kind of love seems important if many important beneficial institutions are to survive. It is also true, probably, that that favoritism is compatible with [the Principle of Relevant Similarity]. Justin evokes my love because he stands in family relations to me that a stranger 'sson does not. These relations, in turn, play a role in justifying Justin's special treatment. In at least some cases, however, I like many people extend favoritism even when I judge x and y to be relevantly similar. (p. 315)

We should not misconstrue Lavin's remark that favoritism is compatible with the Principle of Relevant Similarity, for his intention is to provide a counter-example to that principle; instead, we should interpret his remark as indicating his belief that Condition (II) has been satisfied by his nephew and the neighbor's son being relevantly similar in all moral respects. But Condition (II) has not been satisfied, and Lavin provides us with the clue as to why this is so. Lavin is prepared to extend preferential treatment to Justin, he says, because Justin is his nephew; the fact that Justin is his nephew while the stranger' son is not is a relevant dissimilarity between them - a dissimilarity which must be regarded as relevant to Lavin's judgment regarding, for example, to whom he ought to bequeath his vast wealth. Lest it be denied that the difference in relation (between being a nephew and being a stranger's son) constitutes a moral difference, bear in mind that the preferential treatment we extend to close relations serves, as Lavin points out, to reinforce valuable social structures and institutions. So, if Lavin's relation to his nephew (and the behavior consonant with that relation) in some way serves the interests of, say, justice or fairness within society, then a morally relevant difference surely exists between his relation to his nephew and his relation to some stranger's son. This means that, relative to Michael Lavin and the context in which he must form his judgment, Justin and the stanger's son cannot be regarded as relevantly

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similar. Since Condition (II) has not been met, we can hardly regard this as a counter-example to the Principle of Relevant Similarity.

The only way Lavin could respond to this objection is to somehow restrict what ought to count as a morally relevant similarity, that is, to restrict what counts as a moral property. Lavin only briefly discusses how moral judgments are to be individuated and what moral ontology is required by their individuation. He suggests at one point that a transparent individua- tion of moral judgments is consistent with our "ordinary moral thinking" (p. 314). Consequently, our mere preferences or emotions toward an object should not be considered a part of the content of a moral judgment. In other words, that an object is capable of evoking emotions in us should not be counted among its morally relevant features, unless the emotions elicited are connected to our recognition of some morally relevant feature. So we find Lavin claiming, "that for different emotions to count as a relevant difference, they should be evoked by a morally relevant property of x or y" (p. 314, emphasis his). Presumably, though, in the case under consideration, the love he feels for his nephew is elicited by such a property, that is, if being somebody's nephew (in a society which utilizes social institutions like the family to maintain elements of fairness or justice, and which, consequently, imputes value to family relations) may be regarded as such a property.

Lavin's other example pertains to a woman who, like many individuals in American society, prefers not to eat dog meat but has few qualms, if any, about eating pork:

My sister...would never dream of eating a dog, but relishes pork. A pig, though, is at least as smart and at least as sentient as a dog. Nor does my sister think that her abhorrence for dog on the menu a mere whim. She thinks that people ought not to eat dogs, that eating dogs is wrong. But how can she be right if [the Principle of Relevant Similarity] is true? Dogs and pigs are, so far as I can tell, relevantly similar... So, either some relevant difference between pigs and dogs exists or my sister needs to rethink her diet or [the Principle of Relevant Similarity] is false. (p. 313)

Let us first consider how Conditions (I) and (III) are to be satisfied. Lavin's account is ambiguous enough to accommodate several possibilities: his most exphcit statement of what his sister believes ("that people ought not to eat dogs, that eating dogs is wrong" [p. 313]) suggests that x and y ought to range over some kinds of actions (the eating of dog meat and the eating of pork), yet the morally relevant properties to which he adverts (namely, sentience and intelligence [p. 313] and "the capacity for thought, feeling and volition" [p. 314] are properties of individuals, rather than actions, which suggest that x and y ought to range over particular dogs and pigs.

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Finally, that his sister's beliefs are represented as about dogs and pigs in general suggests that x and y might even be interpreted as ranging over whole classes of objects (perhaps species). The three possible interpreta- tions are not necessarily incompatible. In order to accommodate the different facets of the example, I suggest we let x and y range over actions which are individuated, in part, in terms of the objects toward which they are directed which, in turn, may be individuated in terms of individualistic or non-individualistic properties that are morally relevant. So, if "Fido" designates some arbitrarily selected dog, and "Phideaux" designates some arbitrarily selected pig, then Condition (I) would be satisfied by his sister's judgment that to eat Fido is wrong, and Condition (III) would be satisfied by her judgment that to eat Phideaux is not wrong.

Consider, now, Condition (II). This second condition Lavin takes to be satisfied by virtue of the fact that individual dogs and pigs share the kinds of properties mentioned earlier - sentience, intelligence, etc. Let us grant that dogs and pigs are similar in these ways, so that it is safe to assume that actions directed toward dogs and pigs are, to this extent, relevantly similar. The important question to ask at this point is: why should we assume that an object's individualistic properties alone are relevant to (or constitutive of) the moral facts? In determining whether Fido and Phideaux are relevantly similar, why should we disregard non-individualistic properties they might possess by virtue, say, of the roles which they (and the other members of their species) typically play relative to the family, the pork industry and those who have a stake in it, or even the general condition of the economy? Why should we assume that the morally relevant properties of a thing supervene upon its individualistic properties alone? We can easily imagine a pig farmer explaining to Lavin's sister how each time she and her family eat road-kill instead of buying a ham at the grocery store the farmer's own family is adversely affected. The sort of argument into which this might be developed is exactly analogous to the kinds of argument often heard given in support of the claim that Americans ought to buy American products rather than those produced elsewhere - even though the products in question are in every way relevantly similar in terms of their individualis- tic properties. Those individuals who raise hogs for a living, like those who have a stake in the production and consumption of American products, seem to regard non-individualistic properties of objects as relevant to, if not constitutive of, the moral facts. Since Lavin intends to provide an account at least consistent with our "ordinary moral thinking" (p. 314), and since ordinary moral thinking does not discriminate against non-individualistic properties, we must wonder why Lavin discriminates against such properties. His only discussion of this issue (cf. pp. 314-5; p. 317, n4) wavers between a discussion of the meta-ethical issues and a discussion of

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normative ethical issues irrelevant to the topic at hand. We saw the same discrimination in the earlier example: the property of being a nephew of such-and-such was regarded as irrelevant to the moral facts. So in this case, like the earlier one, Condition (II) has not been met.

Now, it is one thing to show that particular alleged counter-examples to the Principle of Relevant Similarity are inadequate; it is quite another thing to show that any case alleged to be a counter-example to the Principle of Relevant Similarity is doomed to failure. But the fact of the matter is that Conditions (I)-(IV) cannot be simultaneously satisfied. If Condition (II) (which was problematic in the above examples) can be met, then either Conditions (I) and (III) or Condition (IV) cannot be met. We might attempt to satisfy Condition (II) in three different ways.

First, x and y could be considered relevantly similar because they may both be subsumed under some particular moral principle or rule. Obviously, this would constitute a violation of Condition (IV).

Second, we might find or invent a case from which the problematic, non- individualistic properties have been eliminated. As Lavin suggests (cf. p. 317, n4), we might imagine a world in which Fido and other members of her species are not assigned their traditional roles as pets in human families and in which Phideaux and other members of her species do not function as the products of a particular food industry. If the non-individualistic properties which were earlier regarded as constitutive of the moral facts are eliminated from the case, Fido and Phideaux may be regarded as relevantly similar. The problem with this strategy is that if the non-individualistic properties are just those which are constitutive of the moral facts, then by removing these properties, we, in effect, remove the moral facts. In this case, Conditions (I) and (III) would not be satisfied, because the judgments in question could no longer be considered moral judgments. Whether to eat dog meat or pork would not be a moral dilemma; instead, it would be akin to the choice we face when we select ingredients from our garden for a salad. That is, our judgment would pertain to what is prudential rather than moral.

A final strategy exists, one which Lavin would probably find appealing. It requires that only i~adividualistic properties be considered morally relevant. Hence, x and y would be morally similar if, and only if, they possess the same kinds of relevant individualistic properties. On this view, a thing's moral properties are regarded as emergent or second-order properties which supervene upon more basic properties which are capable of being individualistically construed. Consider, for example, the property of being a person (which is a moral property par excellence). Someone who contends that being a person is an individualistic property would presumably argue against those who contend that personhood is, as it were,

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conferred upon us by providing an account of the way personhood super- venes upon more basic properties - say, upon biological, psychological, and behavioral characteristics - which may be individualistically construed. Anyhow, we would adopt this strategy if we wanted to preserve moral facts but eliminate non-individualistic properties from such facts.

It may be objected, though, that the kinds of properties which have (correctly or incorrectly) been regarded as emergent in this way (for example, being a person, having intrinsic value, having inalienable rights) are just the kinds of properties which always figure into moral principles and rules. These are the properties which function as the building blocks for sophisticated moral theories as well as ordinary moral thinking. To think of something as being a person (rather than a non-person), or as having intrinsic (rather than extrinsic) value, or as possessing certain inalienable (as opposed to contingent) rights just is to think of it as the kind of thing with respect to which certain principles hold. Someone who does not acknowledge that a person is the kind of thing with respect to which we observe certain rules and principles lacks any conception of what being a person means. Someone who does not believe that persons should not be indiscriminately murdered does not simply misunderstand or misapply the concept of a person; instead, we would say that someone like this is (to use Wittgenstein's phrase) meaning-blind or conceptually deficient. My point is that the nomological character of a moral property (or concept) appears to grow in direct proportion to its susceptibility for individualistic analysis. Consequently, if Condition (II) is satisfied by adopting this third strategy, then Condition (IV) could not be satisfied.

Since Conditions (I)-(IV) cannot possibly be satisfied simultaneously, we must conclude that the Principle of Relevant Similarity is incapable of being disproven by way of counter-example. Like cases must, indeed, be treated alike.

Notes

1. The Journal of Value Inquiry 22.4 (1988): 313-318. All page numbers in the text refer to this article.

2. For a recent survey of the literature concerning similarity judgments and categorization see G. Lakoff, Women, Fire, and Dangerous Things: What Categories Reveal about the Mind (Chicago: The University of Chicago Press, 1987).