Kripke, Ellis, and Scientific Essentialism

I. Introduction
     Brian Ellis has argued for Scientific Essentialism, a term originally coined by George Bealer in his paper “The Philosophical Limits of Scientific Essentialism.” In that paper, Bealer raises some concerns against the Kripkean position that some essences of natural kinds can be discovered a posteriori. A common natural kind example of water, the essence of water is being composed of H2O. Necessarily, water must be composed of H2O. The essence of water, H2O, was discovered by the natural sciences. Bealer’s concern is about how useful the Kripkean position is for philosophers. Despite Bealer’s concerns, philosophers like Brian Ellis, Caroline Lierse (1992), John Bigelow (1990), and Alexander Bird (2007) have come to embrace Kripke’s insight and make it one of the central themes of Scientific Essentialism.
     This paper will focus on Ellis’s Scientific Essentialism due to the fact that Ellis restricts any discovery of essences to the empirical sciences. However, the Kripkean position only accepts that some essences can be discovered a posteriori. When looking specifically at Kripke’s argument against the mind-brain identity thesis, Kripke presents the example of pain. The essence of pain is its painfulness or the feeling of being in pain. The essence of pain (according to Kripke) can only be discovered a priori. No empirical work can be done to discover the essence of pain. With respect to the pain example, Ellis is silent yet he clearly has to deny the example. The problem for Ellis can be formulated as follows:
(a) Ellis accepts the Kripkean story about natural kinds.
(b) Ellis requires that essences can only be discovered through the
empirical sciences.
(c) If (1), then some essences are discovered a priori.
(d) If (2), then no essence can be discovered a posteriori.
The consequent of (c) and the consequent of (d) contradict so either (a) or (b) has to be rejected.
     First, how Kripke goes from the essence of water is being composed of H2O is an a posteriori discovery to the essence of pain is an a priori discovery will be presented. Second, a few reasons that Ellis (or someone who agrees with Ellis) might be able to give to accept the Kripkean position but reject the story about the essence of pain.

II. Discovering Essences in Kripke
     What makes it the case that some object P has some essence M? An essence M of object P is something the object P must have at every place, time, or possibility in which object P exists. Such an account of essence can be expressed as a biconditional:

(E) M is the essence of P iff (M is with P whenever and wherever P exists
and M is with P whenever and wherever P could exist).

Let us apply (E) to the example of water. There is a glass of ice water near me at the moment and that water has some set of properties, taking the form of the glass, some of the water is in solid form (the ice), and is current at a cold temperature. I wait some amount of time and the water loses some of those properties, the water will become liquid, the water will take the form of my stomach after I drink it, and the temperature of the water will rise, but the water will still exist.
     What could not happen to the water? At first, it seems trivial that what could not happen to the water is that it not be water. It is essential that water is water. Whenever you come across water, you come across water. Such a claim does not seem particularly interesting or informative at first, but what happens when one recognizes that the natural sciences discovered that water is H2O? “Water is H2O” is an identity proposition and with an identity proposition we can substitute an occurrence of one term with the other term in any proposition and preserve the truth of that proposition. From “It is essential that water is water” and “Water is H2O” we get “It is essential that water is H2O.” Combine that last proposition with (E) and we conclude that at any place, time, or possibility, if we come across any water then we will also come across water. Kripke’s argument for H2O as the essence of water can be formalized as follows:

(W1) (Ax)(Ay)(If (x=y) then  (x=y)) (Leibnitz’s Law)
(W2) Water = H2O (Discovery from the empirical
sciences)
Therefore,  Water = H2O (From (W1) and (W2))

     The above argument relies on the authority of science to give us the essence of water and this is where we see the beginnings of Scientific Essentialism. Ellis clearly agrees with the above argument, but this is not the only essence argument which Kripke gives. Next, we need to look at the argument Kripke gives for heat. Kripke acknowledges a distinction between heat and the sensation of heat. The way heat feels to human beings is different from the actual physical phenomena, heat. Kripke claims that science discovered the essence of heat is molecular motion so we can run a similar argument to the water case:

(H1) (Ax)(Ay)(If (x=y) then (x=y)) (Leibnitz’s Law)
(H2) Heat = Molecular Kinetic Energy (Discovery from the empirical
sciences)
Therefore,  Heat = Molecular Kinetic Energy (From (H1) and (H2))

     What about in the case of pain? Is there some divide between the way pain feels and the physical phenomena of pain? Actually, Kripke maintains that pain is the feeling of pain. Consider the claim “Pain is the firing of C-fibers” and if science tells us that such a claim is true do we accept what they say? Kripke’s answer is, no. Why? Because we already know the essence of pain, pain is the feeling of being in pain. Unlike external things like heat and water, pain is something we have immediate epistemic access to and pain is something that cannot be dissociated with the way it feels. One does not have to go to the empirical sciences (according to Kripke) to discover the essence of pain. With that it in mind we get the following argument:

(P1) (x)(y)(If (x=y) then  (x=y)) (Leibnitz’s Law)
(P2) Pain = feeling of being in pain (A proposition any being
who has been in pain knows to be true)
Therefore,  Pain = feeling of being in pain (From (P1) and (P2))

     When we look at Ellis’s work, we see a clear denial of the last argument, “[M]etaphysical necessities have to be discovered by scientific investigation.” For Kripke, scientific investigation will not tell us anything about pain since we already know what is essential or metaphysically necessary for pain. At the same time, Ellis clearly accepts the Kripkean arguments for water and heat.

“Thirty years ago, many Anglo-American philosophers, and probably most Australian philosophers, believed in contingent identities… water is contingently identical with H2O… [heat] is contingently identical with… molecular kinetic energy… Kripke argued, correctly in my view, that the concept of contingent identity is an oxymoron. If a = b, then this relationship holds necessarily, not contingently.”

     Despite this agreement with Kripke, there is no response to Kripke’s pain example and why pain fails to be identical to the feeling of pain. There is no reason from Ellis why we should say that Kripke was wrong with respect to our infallible access to pain. If pain is identical to the feeling of being in pain then scientific investigation cannot tell us anything about pain. Therefore, not all metaphysical necessities have to be discovered by science.

References

To be added soon