Joseph F. LaPorte

According to a doctrine that has been popularized by Kripke and Putnam, a natural kind term like 'bird' rigidly designates the kind with the microstructure of sample birds. This microstructure is the essence of birdhood, so our learning what the relevant microstructure is our discovery of the kind's essence. We have discovered that some statement like 'The bird is the taxon with such and such DNA structure' is true. Further, it is commonly added, the discovered microstructure is essential to each particular bird. ;I argue that this general picture is mistaken. I do accept and defend the view that terms like 'bird' are rigid designators. However, the picture at issue has other difficulties. Individual birds are not essentially birds. And the view that biologists have discovered or will discover that the bird kind is identical to some DNA structure or other type of structure seems wrong. We don't discover just what particular characteristic a kind is to be identified with. Rather, the meaning of natural kind terms changes; as science advances, more sophisticated concepts attending kind terms replace older ones. So the Kripke-Putnam account of our discovering the truth of theoretical identity statements seems wrong. ;Fortunately, the account retains some interest despite its falsity, because of its association with the claim that statements like 'The bird is the taxon with such and such DNA structure' are necessary but a posteriori. The above sentence does not express a truth, much less a necessary truth, but the idea that it could have expressed the sort of necessary a posteriori truth it is supposed to express is epistemologically interesting. The very possibility of such necessary a posteriori knowledge deserves some account. I offer an account, arguing that this sort of knowledge is no more impressive from an epistemological standpoint than is knowledge of analytic necessity: indeed, I argue, it is best understood as knowledge of a species of analytic necessity. Independently of this claim, I argue in a concluding discussion that analyticity ought to be accepted by proponents of the necessary theoretical identity statements in question

Here I defend the position that some singular terms for properties are rigid designators, responding to Stephen P. Schwartz’s interesting criticisms of that position. First, I argue that my position does not depend on ontological parsimony with respect to properties – e.g., there is no need to claim that there are only natural properties – to get around the problem of “unusual properties.” Second, I argue that my position does not confuse sameness of meaning across possible worlds with sameness of designation, or rigid designation. Third, I argue that my position does not founder by way of failing to assign rigidity the work of grounding a posteriori necessity.

According to the received tradition, the language used to to refer to natural kinds in scientific discourse remains stable even as theories about these kinds are refined. In this illuminating book, Joseph LaPorte argues that scientists do not discover that sentences about natural kinds, like 'Whales are mammals, not fish', are true rather than false. Instead, scientists find that these sentences were vague in the language of earlier speakers and they refine the meanings of the relevant natural-kind terms to make the sentences true. Hence, scientists change the meaning of these terms, This conclusions prompts LaPorte to examine the consequences of this change in meaning for the issue of incommensurability and for the progress of science. This book will appeal to students and professional in the philosophy of science, the philosophy of biology and the philosophy of language.

In this paper, I address the charge that the category species should be abandoned in biological work. The widespread appeal to species in scientific discourse provides a presumption in favor of the category’s usefulness, but a defeasible presumption. Widely acknowledged troubles attend species: these troubles might render the concept unusable by showing that ‘species’ is equivocal or meaningless or in some similar way fatally flawed. Further, there might be better alternatives to species. I argue that the presumption in favor of species is not defeated on these scores. Troubles attending species, which arise on account of contextual variation attending the use of ‘species’, do not indicate that the concept is unusable. And alternatives to the use of ‘species’, which have been proposed in connection with rank-free systematics and in connection with conservation efforts, fail to provide a proper replacement for species

In this paper, I address the charge that the category species should be abandoned in biological work. The widespread appeal to species in scientific discourse provides a presumption in favor of the category’s usefulness, but a defeasible presumption. Widely acknowledged troubles attend species: these troubles might render the concept unusable by showing that ‘species’ is equivocal or meaningless or in some similar way fatally flawed. Further, there might be better alternatives to species. I argue that the presumption in favor of species is not defeated on these scores. Troubles attending species, which arise on account of contextual variation attending the use of ‘species’, do not indicate that the concept is unusable. And alternatives to the use of ‘species’, which have been proposed in connection with rank-free systematics and in connection with conservation efforts, fail to provide a proper replacement for species.

It is often said that there is just one “objective” tree of life: a single accurate branching hierarchy of species reflecting order of descent. For any two species there is a single correct answer as to whether one is a “daughter” of the other, whether the two are “sister species” by virtue of their descent from a common parental species, whether they belong to a family line that excludes any given third species, and so on. This position is not right. We may whittle a tree of life, paring troublesome branches, in order to portray an ordering that admits of no legitimate dissent. But the history of life can sustain many legitimate arrangements of the same branches of species. The same can be said about other taxonomically relevant groups besides species, such as “Least Inclusive Taxonomic Units” (LITUs), so the basic claim survives even if we abandon traditional species. Similarly, the claim survives even if we distinguish between synchronic and diachronic groups, even if we consider polytomies, even if we distinguish between models and the world modeled, and even if we recognize an objective world. Nor is the claim merely an epistemic one.

In a recent article, Alex Levine raises a paradox. It appears that, given some relatively uncontroversial premises about how a species term comes to refer to its species, a type specimen belongs necessarily and contingently to its species. According to Levine, this problem arises if species are individuals rather than natural kinds. I argue that the problem can be generalized: the problem also arises if species are kinds and type specimens are paradigmatic members used to baptize names for species. Indeed, the same problem arises with respect to kinds like gold and the samples used to ground names for them. After arguing that the paradox arises whether or not species are individuals, I attempt to show how the paradox can be resolved. Levine's argument that a type specimen belongs necessarily to its species is specious. The appeal of the argument stems from a failure to distinguish between two different modal statements concerning type specimens, one de dicto and the other de re. Type specimens belong contingently to their respective species. Even so, they can be known a priori to belong to them: hence, that a particular type specimen belongs to its species is an example of contingent a priori knowledge.

Rigid designators for concrete objects and for properties -- On the coherence of the distinction -- On whether the distinction assigns to rigidity the right role -- A uniform treatment of property designators as singular terms -- Rigid appliers -- Rigidity - associated arguments in support of theoretical identity statements: on their significance and the cost of its philosophical resources -- The skeptical argument impugning psychophysical identity statements: on its significance and the cost of its philosophical resources -- The skeptical argument further examined: on resources, allegedly overlooked, for confirming psychological identities.

It is often said that there is just one “objective” tree of life: a single accurate branching hierarchy of species reflecting order of descent. For any two species, there is a single correct answer as to whether one is a “daughter” of the other, whether the two are “sister species” by virtue of their descent from a common parental species, whether they belong to a family line that excludes any given third species, and so on. The idea is intrinsically interesting. It has consequences for what we should think about the evolutionary origins of Homo sapiens as well as other species.The idea also has important connections to the scientific discipline of systematics, which classifies organisms into related groups. The connection to systematics is what has made objectivity a topic of discussion for biologists and philosophers of biology. Cladism, now the dominant school of systematics, places organisms into groups depending just on their place in the tree of life. That is supposed to render classifica- tion objective. In section i, I recite claims to objectivity. In sections ii–v, I argue that the apparent objectivity is not what it seems to be. In section vi, I briefly revisit systematics

In this paper I take issue with the doctrine that organisms belong of their very essence to the natural kinds (or biological taxa, if these are not kinds) to which they belong. This view holds that any human essentially belongs to the species Homo sapiens, any feline essentially belongs to the cat family, and so on. I survey the various competing views in biological systematics. These offer different explanations for what it is that makes a member of one species, family, etc. a member of that taxon. Unfortunately, none of them offers an explanation that is compatible with the essentialism in question