The second lecture began by looking at the strength of our essentialist intuitions, and the bad press that essentialism suffers from at the same time. Indeed, if we all have the impression that things could have been otherwise than they are, and that not all the properties of things are essential to them, we find it difficult to distinguish between the essential and the purely accidental (Mackie [1]): no doubt it seems more essential to this person in front of me that he belongs to the human species, and more accidental that he has blond hair. I also find it hard to imagine that my substance could turn into a poached egg, and I naturally believe that I have more in common with a human being than with a donkey or a cauliflower. But after all, what do I know? And, more importantly, how do I account for it? Such is the challenge posed to essentialism. For while it's true that our intuitions lead us to find that, in reality, certain articulations are more natural than others, we've also learned to be wary of our impressions and imagination, which we know can, without a moment's hesitation, send us waltzing off on the side of illusions and prejudices. What's more, when it's not purely and simply suspected of "speciesism" or the most conservative naturalism, essentialism finds itself associated with the bygone era when metaphysics was the queen of the sciences, and when some imagined that by giving the "essential" definition of a stone, by exhibiting both its formal and final cause (the nature of a thing being its end), we would know, from the outset, why the said stone fell: it's because it wants to return to its natural place, which is the Earth (Aristotle). This rejection by scientists and philosophers alike, heirs to the linguistic turn and logical empiricism (see Quine), is not unfounded. Who would still dream of essences, if by that we mean mysterious, anhistorical entities fixed once and for all? Hasn't essentialism been refuted by scientific discoveries such as Darwinism? Isn't all reality subject to the laws of evolution? As John Locke once said: if we want to talk about essences, that's fine: but only on condition that we see in them "nominal" definitions, not "real" ones, and above all that we don't seek in them any knowledge of things [2]. But, as we've seen, Leibniz's ambition was quite different. A certain revival of essentialism in contemporary metaphysics, which in the 1970s went hand in hand with a renewed interest in metaphysics (see last year's lecture), particularly in the forms it took in the analyses of Kripke [3] and Putnam [4], less linked to the "substantialist" conception that Quine was aiming for [5], would rather go in his direction. Since then, discussions on essentialism have been in full swing: attacks by some (Fine [6]) on the modal conception of essence (Kripke and Putnam), but also the development of new forms: scientific essentialism (Ellis [7]), four-dimensional, neo-Aristotelian ontology (Lowe [8]).
Should essentialism be relegated, once and for all, to the storehouse of antiquities and horrors? Can one or other of its new variants meet the challenge? If not, can and should we envisage another model? These are the questions we need to address, starting with a few elements of conceptual analysis. "Essential" is not reducible to "necessary"; it is what defines identity, the full "nature" of the object, what cannot be lost without ceasing to exist (Aristotle). We distinguish between "superficial" essentialism (or essentialism relative to context) and "profound" essentialism (context-independent, absolute); essentialism relative to individuals versus essentialism relative to species; and we note that different epistemological questions arise depending on whether statements concern individuals or species. Some stages in the history of contemporary philosophy were recalled: the rejection of essentialism in metaphysics in various forms: Quinian naturalism, its heirs, the advocates of a "naturalized" metaphysics (Ladyman & al. [9]); but also in the (deflationary) form of "modal" approaches to essence, or reflections carried out in "metametaphysics". In response, two major approaches to contemporary essentialism were presented. For the first (the Kripke-Putnam approach), the distinction between nominal and real essence (Locke) is accepted, but essences, far from being unknowable, are discovered by science. Where, for Locke, all species are the product of understanding, and thus of arbitrary human classifications, Kripke and Putnam make a realistic "semantic" turn: there is overlap between semantic and metaphysical categories; classifications reflect the underlying nature of reality. They are neither arbitrary, nor the reflection of the classifier's pragmatic interests. Indeed, the discovery of real essences is one of the major objectives of scientific inquiry. The second approach is that advocated by Ellis's scientific essentialism: natural species are not limited to things or substances, but relate to events and processes. The essential properties of the most fundamental species are not limited to the primary qualities of classical mechanism; they also include a number of causal powers, capacities, propensities - powers to act, to interact, i.e., properties that are essentially dispositional and imply dispositions to variously act and react according to circumstances: these dispositional properties are fundamental and do not depend on any other property (Aristotle, Leibniz). Thus, a proton will define itself (by means of an actual definition) as any particle behaving as protons do, because no proton could fail to behave in this way, and no particle other than a proton could imitate this behavior. Its identity as a proton is therefore defined by its causal role. As for the laws governing the behavior of protons and their interactions, they cannot be purely accidental. Essentialism appears a more plausible position. It denies the contingency of the laws of nature (the Humian position): laws are metaphysically necessary, and therefore true in all possible worlds. But such a position runs up against three problems: the risk of "pandispositional" idealism, confusion between necessity and identity (yet we must distinguish between: Df1: F is a necessary property of a if a has F in all possible worlds that include aandDf2: F is an essential property of a if the fact of being F is constitutive of theidentity of a), last but not least: essence is then reduced to a pure modality (Kit Fine). Does this mean essentialism has failed? No, and we concluded by beginning to present another possible candidate: narrow essentialism or "aliquidditism", recalling that it constitutes one of the four elements of a convincing dispositional realism (Tiercelin [10]): 1. a causal theory of properties (Shoemaker); 2. a dispositionalist causal analysis of laws; 3. consideration of efficient causality and teleological causality; 4. aliquidditism (narrow essentialism). Essence is understood not as a static "quiddity", or substance, but as a set of properties that are not intrinsic, but relational or dispositional, or groups of causal powers (Shoemaker).
References
[1] Mackie P., How Things Might Have Been: Individuals, Kinds, and Essential Properties, Oxford, Oxford UP, 2009. See also l.a. Paul, "the context of essence", Australasian Journal of Philosophy, 82 (1), 2004, 170-184; republished in Jackson F. and Priest G.(eds.), Lewisian Themes, Oxford UP; "in defense of essentialism", Philosophical Perspectives, 20 (Metaphysics), 2006, 333-372.
[2] See last year's lecture; see also Ayers M., "Locke versus Aristotle on natural kinds", The Journal of Philosophy, 78(5), 1981, 247-272 and Leary N., "How essentialists misunderstand Locke", History of Philosophy Quarterly, 26, 2009, 273-92.
[3] Kripke S., Naming and Necessity, Oxford, Basil Blackwell, 1980; French translation by F. Récanati and P. Jacob, La logique des noms propres, Paris, Minuit, 1984.
[4] Putnam H., "The meaning of 'meaning'", in Gunderson K. (ed.), Language,Mindand Knowledge: Minnesota Studies in the Philosophy of Science, VII, Minneapolis, University of Minnesota Press, 1975, reprinted in Putnam H., Mind, Language and Reality: Philosophical Papers, vol. II, Cambridge, Cambridge University Press, 215-71; "Is water necessarilyH2O?", in Conant J. (ed.), Realism with a Human Face, Cambridge (Mass.), Harvard University Press, 1990, 54-79, French translation by C. Tiercelin, Le Réalisme à visage humain, Paris, Gallimard, 1991.
[5] Quine W. V., "Natural kinds", in Rescher N. (ed.), Essays in Honor of Carl G. Hempel, Dordrecht, D. Reidel, 1969, 5-23.
[6] Fine K. "Essence and modality", Philosophical Perspectives, 8, 1994, 1-16.
[7] Ellis B., Scientific Essentialism, Cambridge, Cambridge University Press, 2001.
[8] Lowe E. J., The Four-Category Ontology: a Metaphysical Foundation for Natural Science, Oxford, Oxford University Press, 2006. See also Oderberg D. S., Real Essentialism, Abingdon and New York, Routledge, 2007.
[9] Ladyman J., Ross D., Spurrett D. & Collier J., Every Thing Must Go: Metaphysics Naturalized, Oxford, Oxford University Press, 2007.
[10] Tiercelin C., Le Ciment des choses. Petit traité de métaphysique scientifique réaliste, Itaque, 2011, 247-359.