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Two Counterexamples to Plantinga's Proper Functionalism

I. Proper function isn't necessary for knowledge: Greco's counterexample
John Greco[1] points out that there are actual cases of people with certain sorts of brain lesions that enhance their memory abilities. If so, then we have cases of knowledge without proper function, in which case proper function isn't necessary for knowledge.

II. Proper Function isn't sufficient for knowledge: Lehrer's counterexample

Keith Lehrer has applied his famous "Truetemp" thought experiment to Plantinga's proper functionalist account of knowledge[2]. According to the thought experiment, physicians anesthetize a patient and implant a device in his head (unbeknownst to the patient) that causes him to reliably form very precise beliefs about the outside temperature. However, Truetemp has no special inner phenomenology associated with the beliefs; nor has he had occasion to check the reliability of his temperature beliefs (say, with a thermometer). Rather, Truetemp just finds himself having these beliefs some time after the operation (and again, he has no idea that the doctors installed the device in his head). So according to the thought experiment, we have a cognitive faculty that, when functioning properly, reliably produces firm and unwavering true beliefs when in epistemically congenial environments. Intuitively, though, Truetemp's beliefs don't count as knowledge. If so, then we have a case of proper function without knowledge, in which case proper function isn't sufficient for knowledge.

[1] Greco, J. 2003. “Virtue and Luck, Epistemic and Otherwise,” Metaphilosophy 34:3, 353-66.

[2] See Lehrer's chapter in Warrant in Contemporary Epistemology, especially pp. 32-33.


Wes said…
I'm not sure I share the intuition that Truetemps beliefs don't count as knowledge. Do you have this intuition? If so, what motivates it?
exapologist said…
Yeah, I share Lehrer's intuition here. Perhaps it's worth emphasizing that Truetemp has no special inner phenomenology associated with the beliefs; nor has he had occasion to corroborate his body temperature beliefs (say, with a thermometer). Rather, Truetemp just finds himself having these beliefs some time after the operation (and again, he has no idea that the doctors installed the device in his head).

By the way: I plan on writing a few more posts on the troubles Truetemp poses for Plantinga's religious epistemology. You've been warned!
exapologist said…
...I should also mention that Plantinga himself shares Lehrer's intuition that Truetemp's beliefs (the one's caused by the device) don't count as knowledge.
exapologist said…
Whoops -- I accidentally deleted Marc's comment when modifying one of my own. Sorry, Marc! Below is Marc's comment:


Just a quick comment regarding Greco's observation.

What if Plantinga suggested that we differentiate between proper function, improper function, and abnormal function? He might then claim, as seems reasonable, that abnormal function doesn't entail improper function (even if there frequently are causal correlations between the two).

Suppose an extraterrestrial pathogen attacked (in some sense) the muscles in my legs, which caused them to become exceptionally strong. Maybe, with my new endowment, I could leap small buildings in a single bound. While I think it's evident that my muscles are functioning well-beyond their normal capacity, which is to say, functioning abnormally, I'm unsure that this constitutes improper function (or malfunction). My muscles, after all, are doing what properly functioning muscles do, just in a rather amplified manner.

Now suppose that another extraterrestrial pathogen attacked (in some sense) the muscles in my legs, which caused them spasm intensely when they were engaged. Like the above, my muscles are functioning abnormally in this situation. But unlike the above, however, my muscles aren't doing what properly functioning muscles do. Muscles are supposed to contract, not spasm intensely, when engaged.

Perhaps the case to which Greco appeals is relevantly similar to the first case above and, consequently, doesn't do significant damage to Plantinga's proper functionalist thesis.


-- Marc
exapologist said…
Hi Marc,

Interesting distinction between abnormal and improper function! But isn't there another sort of case here that's relevant? For besides the categories of:

(i) proper function, outcome achieved
(ii) improper function, outcome diminished
(iii) abnormal function, outcome enhanced

Isn't there also the category of:

(iv) improper function, outcome enhanced

What I have in mind in cases of type (iv) are not cases where the means of achieving the outcome are amplified; rather the means of achieving the outcome are significantly altered for other, at least slightly superior, means. I believe the brain lesion case is supposed to be one of this sort. But in any case, even if such cases weren't actual, they're sufficient to serve as counterexamples if they're merely logically possible, no?

You probably already know this, but for those who don't: this sort of criticism of Plantinga's proper functionalism is typically called the problem of serendipitous malfunction. Papers that raise this criticism include:

(i) Taylor, James. “Plantinga’s Proper Functioning Analysis of Epistemic Warrant", Philosophical Studies 64 (1991)
(ii) Taylor, “Plantinga on Epistemic Warrant,” Philosophy and Phenomenological Research 55 (1995)
(iii) Feldman, Richard. “Proper Functionalism,” Nous 27 (1993)
(iv) Sosa, Ernest. “Proper Functionalism and Virtue Epistemology,” Nous 27 (1993).

TaiChi said…
Ex-Apologist, what are your thoughts on the phenomenon of blindsight? Here too we have proper function in the absence of distinctive phenomenology, or at least, proper function of certain modules which form our visual system. And we can imagine (as Dennett does, in Consciousness Explained) that someone may form beliefs that are very likely to be true with this minimal perception. To my mind, this would count as knowledge, and I imagine that the reason why Truetemp doesn't intuitively produce knowledge is simply that it is too removed from our experiences for the knowledge intuition to kick in.
(If people had the intuition that Truetemp did not produce knowledge, as opposed to the lack of intuition that Truetemp does produce knowledge, then I would be wrong on this. But I don't think anyone has the former.)
exapologist said…
Hi TaiChi,

One might be inclined to invoke Sosa's animal knowledge/reflective knowledge distinction here, and then say that blindsight cases involve animal knowledge, yet not reflective knowledge. However, I'm unable to follow them on this with any conviction, as I'm inclined to think that blindsight cases are not cases of either sort of knowlege. For they seem not to satisfy knowledge's belief condition. As I understand such cases, the blindsighted individuals feel like they're guessing when they make judgements about objects in their "visual" fields.


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