Rock/Hard Place

Not to be too maudlin about it, the comments to my previous post have been much appreciated, and, even, touching. Talk about your rock and your hard place: there's been a lot to write about lately, some of it even less repetitive than most. So it's been hard to hold my tongue/fingers. On the other hand, I still find tension and frustration welling up whenever I read my former usual sources; and, so far, I've managed to click away before it boils all the way to the surface.

Were I still blogging, surely I'd have posted this. Probably I'd have expressed amazement at Roberts' vote, and amusement, with links, to the right wing reaction. Noted that it's sure to galvanize the generally misinformed Obamacare-haters, and wondered the effect on the election.

I guess I'd have mentioned the perfect symbolism of tweeters saying they're moving to Canada to avoid socialism. Teabagger transcendence. Perhaps, for those old enough to get it, I'd have connected to this, too.

And, if I'm worth a shit at all as a blogger, I'd damn well have asked readers to read this.

Given the blatant and revelatory politicking of the vote to hold Holder in contempt over "Fast and Furious," it'd have been hard not to have written about this. Pointed out, I assume, that the program was Bush-birthed. Bad idea then, bad idea now. But conspiracists will have their day, won't they?

So who knows? Fact is, I've been feeling a little less stressed since the high-ate-us, and have found time to read for the pure pleasure of reading, non-political things. Which is very nice. But, given that I've considered this blog mostly an outlet for personal decompression, it's been quite something to read those aforementioned comments....

Sentient plants? Part II

Gene Callahan responds to my recent criticisms of his view that plants are sentient.  (Some plants or all?  Gene seems to think all of them are, though the evidence he appeals to would show at most only that some of them are.)  Recall that I had noted three reasons Aristotelians deny that any plants possess conscious awareness.  The first is that plants lack the specialized sense organs we find in animals.  The second is that plants lack the variability of response to stimuli that animals possess.  And the third is that sensation together with appetite and locomotion form a natural package of capacities, so that since plants lack locomotion they must lack sentience as well.

Gene focuses on the issue of locomotion, and claims that plants can indeed move in something like the way animals do.  In response to the example I gave of dry grass, which cannot move away from sources of heat or seek out water in the way animals can, Gene writes:

Plants can and do do things about circumstances like these.  For instance, the rhododendrons in my yard, in extreme heat, curl up their leaves, lessening water loss.  Plants that undergo periodic dry spells develop deeper root systems than those that do not.

and

[I]t is simply empirically false that plants do not move towards or away from aspects of their environments. They merely do so at a much slower rate than do animals, so it is not readily apparent that they are doing so.  But it has been found that plants "recognize" others of their own species, actively work to drive off plants of other species, and respond to insect attacks with counter-attacks of their own.

In a comment below my previous post, Gene adds:

"[F]linching" is about "moving away from bad conditions."  Plants do that.

The first thing to say in response to all of this is that to establish that something is capable of locomotion (which is what Aristotelians attribute to animals and deny to plants), it is not enough to show that there is some sense in which it “moves.”  Consider: A magnet will either push away from another magnet or draw toward it depending on which of the other magnet’s poles it is facing.  To take an example of “motion” in the broad Aristotelian sense of “change,” a pH test strip will change color when exposed to alkaline.  A wet kitchen sponge will return to its original size and shape after you squeeze it in your hand.  Or consider an instance cited by Bertrand Russell in his essay “Mind and Matter” of “the principle of the conditioned reflex, [which] though characteristic of what is living, finds some exemplification in other spheres.  For example: if you unroll a roll of paper, it will roll itself up again as soon as it can” (in Portraits from Memory and Other Essays, at p. 143).  And then there are examples of artifacts like smoke detectors and outdoor security lamps, which will activate in response to specific external stimuli.

Needless to say, none of these cases is plausibly regarded as involving sentience even though they all involve movement or change of some sort in response to the environment.  And this is so even though in some cases the response is vaguely analogous to the activity of living things -- specifically, to smelling or seeing (in the case of the smoke detector and security lamp), to self-preservation (in the case of the sponge), and to learned behavior (in the case of the rolled up paper).  So, to the extent that the plant movements cited by Gene are comparable to these, they cannot by themselves be indicative of sentience.

Of course, plants are, unlike these phenomena, alive.  And part of what it is, from an Aristotelian point of view, to be alive is to be the sort of thing that is the source of its own motions or changes.  (More precisely, it is to be the sort of thing that exhibits immanentas opposed to merely transeuntcausation.  I have discussed this distinction in some previous posts, such as this one and this one.)  But precisely for this reason, mere motion isn’t enough for the locomotion that the Aristotelian tradition regards as characteristic of animals and absent in plants.  As Aristotelian-Thomistic philosopher David Oderberg defines it in his book Real Essentialism, locomotion is “the capacity and tendency for self-movement from place to place in fulfillment of appetition” (p. 184, emphasis added) and it is, he argues “locomotion of the whole organism that gives evidence of sentience, not a mere reflex in one or other part of an organism that is otherwise rooted to the spot” (p. 188, emphasis added).  

Now one way to understand why sentience would be necessary to locomotion but not to other kinds of motion is as follows (where this is my way of stating things, not Oderberg’s, in case he would not want to commit himself to it!)  Because locomotion involves movement from one place to another, creatures capable of it need to be able to form inner representations of the objects and locations toward which they might move, representations that can guide that movement and that are variable enough to reflect alterations in the environment that arise as the creatures make their way from one place to another.  (For example, such representations need to be able to register the sudden appearance of a physical obstacle to further movement.)  Such creatures also need inner impulses that will cause them to initiate and sustain movement toward the objects of these representations, and those impulses also need to vary with alterations to the environment.  (For example, if a rival predator suddenly appears such a creature might have to shift from a desire to pursue a certain prey to a different impulse, either to fight or to flee.)  Now an animal’s ever-changing stream of conscious experiences performs exactly these functions; and that is, of course, precisely why animals have the complex nervous systems and sense organs they do.  Plants, by contrast, because they do not move from place to place, have no need of such inner representations and impulses and, unsurprisingly, lack anything like the neural and sensory structures that underlie such conscious awareness in animals.  Hence there is simply no reason to attribute sensation and appetite to them.

You might say that plants, unlike animals, need to be little more than stimulus-response mechanisms.  For that reason, behaviorism might be a good theory of plant psychology.  But of course, part of the point of behaviorism was that you don’t need to posit inner states in order to identify stimulus-response pairings -- which is why behaviorism is a lousy theory of animal and human psychology, i.e. the psychology of sentientcreatures.  

In another comment Gene replies to the point about the variability of response in sentient creatures, which is absent in plants.  In an exchange with Gene in the combox of my earlier post, reader Daniel Smith noted that “two identical plants would respond identically to the same stimulus.”  Gene responded: 

Daniel, there is no such thing as “two identical plants”… Go out and look at a bunch of maple trees one day, and try to discover two of them that are identical.

But here Gene commits a fallacy of equivocation.  His response assumes that his critic’s point is that two plants that are “identical” in the sense of being perfect twins, each indiscernible from the other, would react to stimuli in the same way.  And as he rightly points out, there aren’t many plants that are identical to each other in thatsense.  But that’s not the sense of “identical” in question here.  The point is rather that if you took two healthy plants of the same type and (say) two healthy dogs of the same type (whether you have “identical twins” in either case is irrelevant), you would never get out of the former the same variability of response to stimuli that you get out of the latter.  And this is evidence that you do not have in the former, as you do in the latter, inner sensory and appetitive states as intermediaries between the stimuli and the responses, the variability of which accounts for the variability of the responses.

Gene also comments:

And let's remember that fungii, which are vastly different to plants, living in an entirely different manner, do not even have a category in A-T [i.e. Aristotelian-Thomistic philosophy]!

(Gene had also made a big deal in his original post of the purportedly problematic status of mushrooms (!) in Aristotelian metaphysics.)

Now this is, of course, completely irrelevant to whether plants are sentient.  But it also reflects a misunderstanding of what Aristotelians mean by “vegetative” life.  Just as the use of “species” and “genus” in logic and metaphysics does not correspond exactly to the way those terms are used in biology, so too does “vegetative” in Aristotelian philosophy not track in a one-to-one way the use of terms like “plant” in biological science or in ordinary language.  It is used as a technical metaphysical term for those forms of life which, whatever their classification in contemporary biology, have capacities like nutrition, growth, and reproduction while lacking capacities like sensation, appetite, locomotion, rationality, or volition.  And in that technical, metaphysical sense both Fungi and Plantae count as “vegetative” even if they differ in various other ways.  (See Oderberg for discussion of this issue.)

Gene complains that:

In a seemingly common move by modern Aristotelians, [Ed] first plays the “but he doesn't really understand what we are saying” card.

Well, if the move is common, that is for good reason, as I have shown time and again (e.g. here, here, here, here, and here-- and the diligent reader with too much time on his hands can no doubt find many other examples in the blog archives -- not to mention hereand here).  And in his latest remarks Gene only provides a further instance of the phenomenon insofar as (with all due respect to Gene) his arguments rest on a misunderstanding of what Aristotelians mean by “vegetative” and “locomotion.”

Sentient plants?

Economist Gene Callahan (a friend of this blog) calls my attention to this article, which claims that plants are capable of “sensory” responses to their environments, and even that they “talk and listen to one another.”  Gene concludes that “contrary to Aristotle, plants are active and communicate to each other, with sounds among other methods” so that “neo-Aristotelians ought to drop the idea that plants lack sensations.”  And while Gene allows that “this certainly does not invalidate all of Aristotle's metaphysics,” it does in his view show that Aristotelians should be wary of once again “ma[king] the mistake of tying Aristotelian metaphysics to Aristotelian natural science.”

But (no disrespect to Gene intended) as usual with these breathless journalistic “Science has shown that…!” stories, the actual facts are far less exciting than the sensationalistic packaging would suggest.

  

What the article describes when it gets down to the details is the following:

Using powerful loudspeakers, researchers at The University of Western Australia were able to hear clicking sounds coming from the roots of corn saplings.

Researchers at Bristol University also found that when they suspended the young roots in water and played a continuous noise at 220Hz, a similar frequency to the plant clicks, they found that the plants grew towards the source of the sound…

[P]revious research from Exeter University found cabbage plants emitted methyl jasmonate gas when their surfaces are cut or pierced to warn its neighbors of danger such as caterpillars or garden shears.

Researchers from the earlier study also found that the when the volatile gas was emitted, the nearly cabbage plants appeared to receive the urgent message that [sic] and protected themselves by producing toxic chemicals on their leaves to fend off predators like caterpillars.

What has been shown, in other words -- if these claims are correct, anyway -- is that plants are sensitive to sounds (or at least to the vibrations associated with sounds) and to gases.  But so what?  Aristotelians, like everyone else, have long known that plants are in various ways sensitive to their environments -- that they will grow toward light, sink their roots in the direction of water, etc.  They have long known how a Venus fly trap will react to the presence of an insect and how the Mimosa pudica will respond to touch.  And they have long had a response to those who falsely suppose that these sorts of phenomena imply sentience.  Gene seems to think the article in question provides cutting-edge scientific evidence that “whether anything at all has a ‘vegetative soul’… it ain't plants.”  Yet the objection he raises is explicitly dealt with in books like George Klubertanz’s 1953 volume The Philosophy of Human Nature and Henry Koren’s An Introduction to the Philosophy of Animate Nature, published in 1955.  The subject is also treated at some length in David Oderberg’s recent Real Essentialism (at pp. 183-93).  What we have here, in the case of criticism of the Aristotelian conception of vegetative life (and with all due respect to Gene), is something often seen in criticism of Aristotelian ideas in natural theology, philosophy of mind, and ethics -- namely a failure to understand what Aristotelian writers actually mean by the technical terms they use, or to bother to read what they’ve written so as to find out what they mean.  

What Aristotelians do mean when they deny sentience to plants is not that plants are incapable of receiving information from their environments in ways that are in some respects analogous to sensation, but rather that in plants, unlike animals, there is no conscious awareness associated with the reception of this information.  In other words, what they mean is that there are nothing like qualia in plants, as there are in animals.  There’s something it’s like to be a bat, a dog, or a bird; but there’s nothing it’s like to be a tree, a blade of grass, or even a Venus fly trap.  That roots grow toward water doesn’t entail that plants feel thirst, and that plants grow toward light doesn’t entail that they feel heat or see the sunshine.  Similarly, if some plants are sensitive to vibrations and gases, it doesn’t follow that they hear or smell.

Nor is the reason Aristotelians would deny awareness to plants a matter of dogmatic a priori metaphysics (though metaphysical considerations have something to do with it).  As always when determining the natures of things, we must, for the Aristotelian, stick to the empirical evidence.  Koren writes:

It would be irrational to admit potencies implying awareness in plants if they do not show any signs of awareness, for one does not admit anything for which there is no evidence.  But in plants there are no signs of activity involving awareness.  Therefore, we cannot admit that plants have any potencies implying awareness, such as sensation and intellection.

The minor premise of this argument is attacked by opponents who point to so-called tropisms in plants, i.e. to the way they respond to physical stimuli… (p. 72)

Examples of the sort already mentioned follow, after which Koren says:

These facts would settle the argument in favor of sensation if they could be explained only as responses following upon the awareness of the physical stimulus by which they are provoked. But if these facts can be explained equally well without awareness, as purely physical and mechanical responses to physical stimuli, this explanation has to be preferred, because it would be unreasonable to assume the working of a higher cause for effects which can be explained equally well by a lower cause.  (Ibid.)

Yet there is simply nothing in the phenomena in question that requires attributing awareness to plants as opposed to mere unconscious sensitivity to certain specific environmental triggers (of the sort evident in, say, a smoke alarm or an outdoor security lamp).  Moreover, as Aristotelian writers emphasize, there are at least three key aspects of sensation in animals that are absent in the case of plants.  First of all, there are in animals specialized sense organs associated with their various forms of awareness -- eyes with visual awareness, ears with hearing, and so forth.  There is nothing like that in the case of plants.

Second, sensation in animals is associated with a variability of response that is not present in plants.  Unless it is in some way damaged, a plant will, say, simply grow toward the light or sink its roots downward in response to the relevant stimuli.  A properly functioning animal, by contrast, may respond in a number of different ways to stimuli presented to it.  For example, an animal might immediately leap toward the prey it sees, or sneak up toward it slowly, or refrain from acting at all if it sees another, stronger predator in the vicinity or some barrier it is afraid to cross.  A conscious perception functions as a kind of intermediarybetween external stimuli and different possible behavioral responses, an intermediary that makes this variability of response possible.  That plants lack such variability is thus a reason to think they lack anything like such intermediary, conscious states.

A third point -- one that combines specifically Aristotelian metaphysical considerations with empirical considerations -- is that for the Aristotelian, sensation naturally goes together with the other traditional characteristics of distinctively animal life, namely appetite and locomotion.  The three features are not, in the Aristotelian view, merely accidentally associated in animals, but form a kind of package.  An animal is aware of various aspects of its environment for the sake of the motions toward or away from those aspects that that awareness makes possible, and feels drawn toward or repelled by those aspects as a consequence.  Thus the absence of locomotive and appetitive powers in plants is evidence that awareness is absent as well, for awareness would be pointless in that case.  Indeed, it might even be harmful.  As Klubertanz writes:

For example, grass lacks the organic structure necessary for any form of sensation.  Moreover, it would be an evil for grass to have either sensation or appetite.  These activities would be useless, for grass has no power of external action which could be modified (controlled) by knowledge.  The activities would be directly an evil, for they would be a source of great suffering without any compensating advantage.  Nature is the source of operations for the good of the being; a nature which by supposition would be the source of operations for its own evil would be a contradiction.  (p. 58)

Hence, imagine that dry grass could feel the oppressive heat of the sun or experience thirst and the craving for water.  What would be the point?  It would not be able to do anything about its circumstances and would thus, unlike an animal, suffer without being able even in principleto remedy the circumstances leading to that suffering.   And this would violate the Aristotelian principle that nature does nothing in vain.  (But what about animals with disordered appetites or wounded or deformed organs?  Aren’t they counterexamples to the claim that nature does nothing in vain?  They are not, precisely because such animals are not in their natural state, precisely because they are in various ways deformed.)

Nor need one accept the general Aristotelian philosophy of nature to see the force of this consideration.  For how could conscious awareness evolve in a creature that was not capable of locomotion, given that the way such awareness typically manifests itself is via behavior and given that it is such behavior which would, presumably, be either adaptive or maladaptive?  Of course, the critic might respond that awareness might have developed as a “spandrel” in the Gould/Lewontin sense of being a non-adaptive byproduct of some other trait which was adaptive.  But there’s no point in suggesting that some trait is a spandrel until we know it exists, and whether awareness really exists in plants is precisely what is in question.  Furthermore, it is hard to see what mechanism there could be for awareness in plants even as a spandrel, given that they lack sense organs.  

(Note also that Michael Tye, arguing from a naturalistic rather than Aristotelian point of view, has given similar reasons for denying that plants have qualia.)

Those who claim that plants possess conscious awareness might at this point respond by saying that the notion of a “zombie” (in the philosophical sense) shows that conscious awareness has no adaptive value in any case, not just where plants are concerned but even where animals and human beings are concerned.  But there are two problems with such a response.  First, the Aristotelian will not agree that zombies really are metaphysically possible; as I have argued in several places (e.g. chapter 8 of Philosophy of Mind and chapter 4 of Aquinas), the notion of a zombie makes sense only against the background of a post-Cartesian, mechanistic conception of matter and not on an Aristotelian conception.  Hence to appeal to zombies would just be to beg the question against the Aristotelian.

Second, for the defender of plant sentience to appeal to zombies would only undermine his own case, for it would rob him even of the slender evidence on which that case rests.  For if there is no essential connection between an animal’s locomotive behavior and conscious awareness, then there is certainly no essential connection between the less dramatic, non-locomotive responses of plants to their environments (growing toward the sunlight, etc.) and conscious awareness.

So, there is simply no good argument for awareness in plants.  Those who claim otherwise are, I submit, not thinking about the matter very carefully.  They ignore crucial differences between plants and animals while magnifying superficial similarities.  In this respect their arguments are like those purporting to show that some apes have linguistic abilities comparable to those of small children -- about which Noam Chomsky once aptly said: “That's about like saying that Olympic high jumpers fly better than young birds who've just come out of the egg -- or than most chickens.  These are not serious comparisons.”  

Bottom line: If that weed seems to be “communicating,” that could just be ‘cause you’ve been smokin’ it…

Done

Nope, I can't take it any more. I could post twenty items a day, as the outrages keep adding up; but several things are clear, and it's not as if they never were: It'll never stop, and there's nothing I can do about it. Americans have become stupid and selfish and more than willing to accept lies to justify it all. Reading about it drives me nuts, I run to this blog to say something, but writing about it only helps for a moment or two. And it makes not a dime's difference, especially since we've happily turned our politics over to a handful of billionaires, who've made people look away from what they're doing by creating, very successfully, a phony image of President Obama. (Who's far from perfect, anyway. But, unlike teabaggRs, at least he's trying.)

It's like what a friend said about the lottery: it's the only game where the odds of winning are the same whether you play it or not. Only in this instance, it's losing. Except for those who rigged the game and need it the least.

Judy says I shouldn't delete this blog, so I won't. For now. I like writing, for its own sake, and I need to find an avenue for it. It'll be hard to keep my fingers shut, because the urge to vent is strong. Maybe I'll post an essay once in a while, about stuff unrelated to politics. I might have a couple of letters to the editor left in me. As November approaches, I'd like to implore readers of local papers to look into their hearts before voting to deny marriage rights to same-sex couples; ask them to ask themselves how it hurts their own marriages, to place the humanity of their fellow men and women above their own prejudices. Or something. I'll try to make it inoffensive. Do-unto-othersy.

Perhaps at some point I'll risk having my point missed and write a sarcastic letter, saying "I got mine. I'm old, my kid got his public, then Ivy-League education, I got my Medicare and Social Security, my wife's about to. Since my elders in Portland have died off, I don't drive there as much as I used to, so I don't mind a few potholes. I have fire insurance, and my house is paid for. So's my car. There'll be enough oil to last my lifetime and I'm too old to care if the air becomes unbreathable or the water causes cancer. I've always thought I'd rather die of cancer, anyway: give me a little prep time. I fought my war, did my part, I figure I deserve everything I have and if there's nothing left for you, so the fuck what. So, yeah, who cares if the Romney/Ryan budget eliminates our ability to pay for what we need? Let me keep my money and let the country rot. But not before we fling a few nukes into the Middle East. I got mine, so go to hell, USA, USA, USA."

[Meanwhile, since I took down an earlier uplifting post, I've heard some people liked it. It was just a link to this. Wish it were that simple.]

Pick Up, PT: It's Cato Calling

Read it, PT. Someone else did.