Tom Morris, in his book The Logic of God Incarnate, defends the following claim: Jesus coexemplifies all the kind-essential properties of humanity and all the kind-essential properties of divinity. His strategy is to deny that the kind-essential properties of humanity are logical complements of the kind-essential properties of divinity. This will show the coherence of the traditional claim that Jesus is God the Son. A crucial component to his strategy is to distinguish between kind-essential properties of humanity and merely common or universal properties of humanity.
Here�s a problem with Morris�s defense that I posed to several folks in our reading group and I thought I�d pass it along for further input: Take the property omnicompetence (call this property �C�). Let us say that a kind-essential property of divinity is essential omnicompetence (or C). Apply Morris�s strategy. Full-humanity cannot include any property that contradicts essential omnicompetence. So full humanity cannot include the property ~C. But full-humanity cannot include the property C because�alas�you and I do not exemplify omnicompetence but we do exemplify full-humanity. But for any kind K the set of K�s kind-essential properties either includes property p or property ~p. So the set of the kind-essential properties of full-humanity includes either C or ~C. But either way this won�t work for Morris�s defense.
Let me say a bit about the crucial claim: for any kind K the set of K�s kind-essential properties either includes property p or property ~p. The set of K�s kind-essential properties is the set of properties individually necessary and jointly sufficient for an individual to be a member of that kind. (For example, the set of humankind�s kind-essential properties is the set of properties individually necessary and jointly sufficient for an individual to a member of humankind.) Our interest in natural kinds seems to grow out of our interest in an individual�s causal powers, dispositions, and relations. Hence the set of K�s kind-essential properties should inform us about the causal powers, dispositions, and relations of that natural kind. Think for example of Plantinga�s use of world-books. The book on a world is the set of propositions true at the world. Similarly we can think of the book on a natural kind as the set of properties an individual must exemplify to be member of that kind. This book will inform us as to the actual powers and possible powers of any individual that exemplifies kind K. Intuitively, then, the sentences in the book will read as follows: an individual of K is essentially �; an individual of K is not essentially �; etc. If the properties in question are shareable�i.e., not haecceities�then it seems the book on a natural kind K will specify for each shareable property whether K includes essentially p or not-essentially p.
Ted, I think the argument is not convincing yet. Kind K can have essential properties that kind K* lacks without generating a contradiction. Suppose it is essential to being a gun that it can be fired. It is not essential to plastic that it can be fired. Yet, guns can be made out of plastic.
So K can be []C and K* can be ~[]C and yet some individual be an instance of both K and K*. What is prohibited is K being []C and K* being []~C.
Hi Jon, As I understand Morris�s position he denies that an individual can coexemplify the property p and the property ~p. I would have thought that this holds for any substitution instance. Perhaps modal properties pose a problem. An individual clay statue exemplifies the property of [](being a statue) but in virtue of being a lump of clay it exemplifies the property of ~[](being a statue). An individual human person�say, Socrates�exemplifies the property of [](Socrateity) but in virtue of being a human person exemplifies the property of ~[](Socrateity). I�m not sure what to think about this�I tend to deny that the latter are kind-essential properties of clay (in the first case) and human-kind (in the second case). Intuitively no individual can coexemplify []P and ~[]P. If individual b exemplifies []P then in every b-world b exemplifies P. But if individual b exemplifies ~[]P then there�s some b-world in which b exemplifies ~P. Maybe there�s some wiggle room in the difference between an individual essence and a kind-nature, but I don�t see it yet.
The plastic gun case is interesting. An individual exemplifies both GUN and PLASTIC (caps to indicate natural kind). But a kind-essential property of GUN is [](possibly fired), and a kind-essential property of PLASTIC is ~[](possibly fired). But clearly there are plastic guns. If the individual exemplifies both natures then it exemplifies [](possibly fired) and ~[](possibly fired). Given the above I�m tempted to deny that the counterexample is possible. If I took this line I�d probably argue that the existence of plastic guns shows that PLASTIC includes the property [](possibly fired). If an individual p belongs to the kind PLASTIC then in every p-world there�s some accessible p-world where p is fired.
Ted, you don't have to be Morris to see that property p and ~p can't both be exemplified! But the kind examples aren't examples of that sort. The kind HUMAN doesn't include being necessarily Scandinavian, i.e., ~[]S. But the kind SCANDINAVIAN includes being necessarily Scandinavian. And there are Scandinavian humans. This isn't an instance of one thing being both p and ~p; it's rather a question of what a kind term precludes or doesn't preclude.
Jon, I�m glad basic commonsense is not limited to ND grads and former professors! Do you intend the property of being []S as a counterexample to principle I appealed to�for any kind K the set of K�s kind-essential properties either includes property p or property ~p? Human-kind neither includes the property []S nor the property ~[]S. But that doesn�t sound right. Human-kind includes the property ~[]S. Scandinavian humans are not essentially Scandinavian�Sven could have been Swedish.
Also could you explain how your last remark connects with property exemplification: �it's rather a question of what a kind term precludes or doesn't preclude.� If a kind K precludes the property []p then any individual that exemplifies its complement isn�t a member of that kind. Right? Also if a kind K does not preclude the property []p then an individual can exemplify []p and be a member of K. Does it also follow that an individual can exemplify ~[]p and still be a member of K? If so then the principle I appealed to is false. Good! No problem for Morris�s view!
Pah. I would do no such thing. I am an atheist, after all. ;)
The principle you just formulated, Ted, has no bearing on this discussion. It's just excluded middle.
So here's the challenge. I'm a scandinavian human, so the kinds are compatible. But they have different essential properties. From that it follows that p is an essential property of HUMAN that is not an essential property of SCANDINAVIAN. This is all about kinds, not about individuals, so talking about Sven is irrelevant. To get conflict between kinds, you need to find a property essential to one kind the negation of which is essential to the other. I'd say the kind ROCK and HUMAN display that kind of conflict, but not SCANDINAVIAN and HUMAN, nor SCANDINAVIAN PHILOSOPHER and ADMIRER OF MORRIS!
Tom, I hope that's you! If it is, what happened to the days of the fountain pen as the height of technology????
Thomas V. Morris that is.
Jon,
Thanks for the comments�I too exemplify the property of being an admirer of Morris�s work. The challenge I posed is intended to help think more clearly about Morris�s position.
The argument has the form of a dilemma. The main premise is an instance of the general principle I appealed to. Either []C or ~[]C is a kind-essential property of full-humanity. If []C then you and I do not exemplify full-humanity. If ~[]C then Jesus cannot exemplify full-humanity. So either I do not exemplify full-humanity or Jesus cannot exemplify full-humanity.
A weaker principle that drops the modalities does not work. The principle �either p or ~p is a kind-essential property of full-humanity� is false. Counterexample: p=white. One needn�t be white to exemplify full-humanity and one needn�t be non-white to exemplify it. One exemplifies full-humanity just in case one exemplifies every kind-essential property of full-humanity. In my original post I tried to motivate the stronger version with the modalities and restricting the properties to �shareable� ones.
Jon,
It occurred to me that there�s a crucial ambiguity in the principle I appealed to.
We need to hold separate two claims: (a) every individual exemplifies either property P or ~P (i.e., (Vi)(Pi or ~Pi)) and (b) either every individual exemplifies property P or every individual exemplifies the property ~P (i.e., ((Vi)Pi or (Vi)~Pi)). I think that your comment re LEM reads the principle I appealed to along the lines of (a) rather than (b). The principle about natural kinds can (I think) be formulated as follows:
�V� is the universal quantifier; �e� expresses the member-relation.
(1) [](VK)(VP)((Vi)((i e K)--> []Pi) or (Vi)((i e K) --> ~[]Pi)).
(That�s to say: Necessarily for every kind and every property either for every individual if an individual is a member of K then the individual exemplifies []P or for every individual if an individual is a member of K then the individual exemplifies ~[]P) {I hope that�s right. In my previous post I noted that there�s a counterexample for a weaker version of this principle that drops the second and third occurrences of �[]�.}
This is not to claim that:
(2) [](VK)(VP)(Vi)((i e K)--> []Pi) or ((i e K) --> ~[]Pi)).
(That�s to say: Necessarily for every kind, property, and individual then either if the individual is a member of K then it exemplifies []Pi or if the individual is a member of K then it exemplifies ~[]Pi. I think this principle follows from LEM).
Now Morris�s position seems committed to the falsity of (1). The book on a natural kind will not be complete, i.e., there will be some properties that the book will not specify with K includes []p or ~[]p. To see that Morris�s position implies this consider his remarks on the property of contingent existence (�CE�). It seems reasonable that HUMANKIND includes the property []CE. But this precludes the possibility of an incarnation because DIVINITY includes the property ~[]CE. Now Morris tries to accommodate the intuition that []CE is one of our properties by claiming that it�s either a property of MERE-HUMANITY or it�s a property of individual essences. On the other horn, though, HUMANKIND cannot include the property ~[]CE because you and I are members of H and exemplify its complement. I suspect (1) is the offending principle but it seems reasonable that the book on a natural kind would be complete with respect to essential properties.