Monday, June 25, 2012

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 immanent as opposed to merely transeunt causation.  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 sentient creatures.  

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 that sense.  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 here and 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.”

37 comments:

equesatrum said...

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

What's frustrating is that Dr. Feser "played the card" and then went into great detail to show what you actually meant, in a way that is accessible to everyone, twice now.

That seems to be the way these conversations go, and I have to admit, it can be very discouraging.

equesatrum said...

you = Dr. Feser

Anonymous said...

I just have to say that these comic book illustrations that accompany the posts are extremely hilarious! :-)

~ Mark

James said...

“I just have to say that these comic book illustrations that accompany the posts are extremely hilarious! :-)”

Agreed; I’m baffled how he’s able to find just the perfect illustration. Have a grad student do this sort of thing?

Anonymous said...

Hello Dr Feser

I've really enjoyed your blog, it's both interesting and stimulating. Seeing that you have been defending A-T metaphysics and Aqunais' theology from the mechanistic view of nature, will you be putting some posts defending the same view from what is apprently an attack by Eastern Orthodoxy? I myself am not orthodox (but high church Anglican), but reading on this (A-T) subject, it seems that Orthodxy's practice of hesychasm is somehow at odds with A-T metaphysics. Why would they say that and what is Western Christianity's response to it?

I'm sorry for being off topic, but seeing that this is the most recent post, you'll probably pay more attention to it.

Mr. Green said...

Mark: I just have to say that these comic book illustrations that accompany the posts are extremely hilarious! :-)

The question is, does the Profeser search the web for these images and manage to come up with appropriate panels every time, or is he pulling these from his own extensive, and apparently thoroughly cross-indexed and/or fully memorised, personal collection?

Ismael said...

I am not sure how Callahan can conclude that response to a stimulus or even movement constitutes as sentience.

At least in my opinion it does not follow that such properties and capabilities entail sentience.

A mechanical machine (with gears and no electronics) could do that.

Or a dead animal, for that matter.
Dead frogs respond to electrical stimuli to their nerves (think of Galvani's experiment)... and they have no sentience since they are dead.

A piezo-crystal moves (contracts and expands) under the influence of an electric field.

What I mean is that, clearly, sentience is more than just mere response to a stimulus, since even non-living beings can respond to stimuli and move, etc...

Perhaps I am misunderstanding Callahan’s argument...?
--
Dr. Feser, you state:

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.


Could one argue that these properties (although perhaps I am intepreting the properties in a modern sense, which I admit might be mistaken) are in themselved not enough to indicate sentience?

Such properties and capabilites could apply, except for "appetite" of course (which is not meant in the modern sense, that's for sure), to machines, even meccanical machines, without 'artificial computer brain' or other fancy parts.

Vincent Torley said...

Hi Ed,

I've been following this discussion with some interest. You see, I did my Ph.D. thesis a few years ago on animal minds - more specifically, on the most basic kind of mind that an animal could possibly possess. Here's the link:

http://www.angelfire.com/linux/vjtorley/Anatomy.pdf

I discuss various definitions of consciousness on pages 77 to 111. The long and the short of it is that I give short shrift to most of the various definitions of consciousness put forward by recent philosophers, as they do not carve nature at the joints. I also critique behavioral criteria for the possession of consciousness, arguing that they don't work. If you define consciousness as possession of senses, then you could say most animals have it (see below). If you're talking about phenomenal consciousness (which si roughly the same as what neurologists call primary consciousness), then the only reliable criteria for its occurrence in non-human animals are neurological, and the available evidence suggests that only mammals and birds possess it (and just possibly, reptiles and cephalopods). As for fish and amphibians, forget it.

My discussion of senses in various organisms (including bacteria and plants) can be found on pages 158 to 173. A short summary:

"Definition - 'sense'

(a) On a broad definition of 'sense', any organism possessing (i) sensors that can encode and store information relating to a stimulus, and (ii) a built-in capacity to measure the degree of change in the sensor's state when it encounters the stimulus, can be said to sense the stimulus.

(b) On a narrower definition, the verb 'sense' can be restricted to organisms satisfying the conditions in (a), whose sensors are dedicated receptor cells which trigger a distinctive, built-in, rapid-response motor pattern which is specific to the signal and independent of the organism's internal state.

Conclusion 2.5: On the broad definition used above, all cellular organisms (including bacteria) can be said to possess senses. On the narrower definition, senses are confined to organisms with nervous systems, and appear to exist in two species of jellyfish, as well as all 'higher' phyla of animals."

I late conclude that plants are incapable of internally generated truly flexible behavior (associative learning).

I also discuss the notion of representation on pages 248 to 255. I define a minimal map as follows:

A minimal map is a representation which is capable of showing:
(i) an individual's current state,
(ii) the individual's goal and
(iii) a suitable means for getting to the goal.
A minimal map need not be spatial, but it must represent specific states.

I conclude that fruit flies can indeed be said to have bona fide minimal maps of their surroundings. The funny thing is that they use these maps and navigate their way around, despite lacking phenomenal consciousness. The cognitive feats of honeybees are even more amazing, despite their total lack of phenomenal awareness (see pages 299 to 308 - by the way, the definition of "concept" which I employ in that chapter is a broader one than yours, Ed).

I go on to define four kinds of minimal minds in chapter 9 of my thesis. All of these kinds of minds lack phenomenal consciousness, despite possessing inner representations.

We live in a strange world.

Kvetch said...

"I just have to say that these comic book illustrations that accompany the posts are extremely hilarious! :-)"

Absolutely. Perhaps his next book will be entirely in comics..

By the way, there was an excellent discussion on Dr. Feser's most recent Philosophy of Nature post about how substantial form and evolution are compatible. I think that subject deserves a post to clear things up.

rank sophist said...

I've really enjoyed your blog, it's both interesting and stimulating. Seeing that you have been defending A-T metaphysics and Aqunais' theology from the mechanistic view of nature, will you be putting some posts defending the same view from what is apprently an attack by Eastern Orthodoxy? I myself am not orthodox (but high church Anglican), but reading on this (A-T) subject, it seems that Orthodxy's practice of hesychasm is somehow at odds with A-T metaphysics. Why would they say that and what is Western Christianity's response to it?

At risk of going off-topic, I'd like to respond (briefly) that there have been a historic number of misunderstandings between Eastern Orthodoxy and Thomism. Aquinas's own Contra errores Graecorum attempted to clarify the issue in the 1200s, but, clearly, it didn't work that well. Things were further complicated by the attack of hesychasm in the 1300s by Barlaam of Seminara, who has traditionally been classified as a Thomist. Barlaam was in fact more likely an Ockhamist, given many of his stated theological positions--which is why he took issue with hesychasm.

Anna Ngaire Williams argues in The Ground of Union that Aquinas and Palamas were actually on the same page regarding deification, and that the conflict between Eastern and Western Christianity has been the result of continued misconceptions on both sides. I haven't read the entire book yet, but it seems very promising. You might consider checking it out.

Anonymous said...

Anonymous @ 7:38 said:

>Seeing that you have been defending A-T metaphysics and Aqunais' theology from the mechanistic view of nature...

That was probably a slip of the keyboard. Dr. Feser does not defend A-T metaphysics from the mechanistic view of nature. He explicitly and repeatedly rejects the mechanistic approach.

Gio said...

"The question is, does the Profeser search the web for these images and manage to come up with appropriate panels every time, or is he pulling these from his own extensive, and apparently thoroughly cross-indexed and/or fully memorised, personal collection?"

Well I did a google image search with the panel near here and the only result was... this blog post. ;)

Gene Callahan said...

"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 here and 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..."

With all due respects to Ed, when you first made this remark you claimed that I didn't understand that when Aristotelians talked about sentience in plants, they were referring to qualia and it being something which it is like to be a plant. But I understood that quite well, and that's what I noted!

It's not really playing fair to point out now that there were some other subtleties of the A-T view I *didn't* understand when I made that response, because I was not claiming to be an expert on all aspects of A-T philosophy -- I certainly am not! -- but just claiming that I understood your first points perfectly well.

Gene Callahan said...

@equesatrum: 'What's frustrating is that Dr. Feser "played the card" and then went into great detail to show what [he] actually meant..."

No, no, equesatrum: The first time he "played this card" and I protested, he said I hadn't understood that he was talking about qualia. I had understood that perfectly well, which is what I noted. And Ed doesn't now dispute that I understood that: instead, he notes there are *other* aspects of the A-T view of plants I haven't understood. And as no expert in A-T philosophy, I readily grant that that is true. All *I* claimed is that he was wrong in claiming I hadn't understood the matter of qualia!

Gene Callahan said...

"That was probably a slip of the keyboard. Dr. Feser does not defend A-T metaphysics from the mechanistic view of nature."

"To defend from" can be synonymous with "to defend against."

Gene Callahan said...

'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”'

This is merely to beg the question of whether something that has taken up a stationary lifestyle can be sentient!

rank sophist said...

This is merely to beg the question of whether something that has taken up a stationary lifestyle can be sentient!

On the contrary, Oderberg takes great pains to explain why locomotion and sentience are necessarily connected, both in terms of evolutionary biology and metaphysics. It starts around page 184. I can't provide the full excerpt now, but perhaps later on.

Josh said...

Rank,

It is pg. 184(!):

"Sentience at its most basic is the capacity and tendency for awareness of stimuli. Appetition is the capacity and tendency for seeking after and avoiding stimuli consequent upon awareness of them. Locomotion is the capacity and tendency for self-movement from place to place in fulfilment
of appetition.
"

Josh said...

Of course, Ed emphasized the notion of appetition in the original quote, but that seems to have fallen by the wayside in the subsequent critique...

Edward Feser said...

Gene,

First of all, you are putting words in my mouth. I never said that the point about qualia was the only thing you misunderstood.

Second, if you don't claim to be an expert on what the A-T view about plant life actually is, then maybe you shouldn't be making these peremptory statements about how the A-T view about plant life has been refuted.

Third, neither I nor Oderberg has begged the question. I have given reasons why locomotion would require conscious awareness and appetite while mere response to stimuli in a non-locomotive organism would not. I have noted some crucial respects relevant to sensation in which plants and animals differ -- the lack of sense organs and the lack of variability in response to stimuli. You have said nothing in reply to those reasons. Oderberg also gives arguments (as I have said before, his treatment of this subject occupies about ten pages -- you should read them).

Edward Feser said...

I just have to say that these comic book illustrations that accompany the posts are extremely hilarious!

Thanks -- I am gratified to know that I am not the only one getting a few laughs from them!

Sometimes (I am either proud or embarrassed to say) I just know from memory of all the comics I've read over the years some image that will fit a post perfectly. (That was pretty much the case in these last two posts -- Harvey Kurtzman's "The Sounds From Another World" is a classic well-known to EC Comics buffs, and Lee and Kirby's bizarre "Save Me from the Weed!" though not as well known, kind of sticks in the mind once you've read it. Sounds like a public service anti-dope comic, but in fact it's a science fiction story about a weed mutated by radioactivity into a sinister intelligence bent on world domination, or some such thing...!)

Other times I hunt around until I find something I like. Sometimes it seems to take longer than writing up a post!

Anonymous said...

@ Anon 12:17: "That was probably a slip of the keyboard"

It was, otherwise my Q about Orthodoxy would not make sense. My bad. suppose to read : "against the mechanistic view of nature". This is what happens when you go back to change what you've originally typed in haste but you don't read over what you've changed.

@ rank sophist: This is the first time that I hear someone say that its all a big misunderstanding. From all that I've read on both sides (East and West), they seem to be quite certain in their understanding and criticism of the doctrine of the other side. Also, from what I undersatnd, (I stand to correction in this) Contra Errores Graecorum deals mainly with the filioque clause, papal primacy, unleaven bread in the Eucharist and purgatory, not the scholastic approach to theology.

The book you mentioned takes an interesting position, will certainly check it out. Although I still hope that Dr Feser could put up a few blog posts to address the issue.

Anonymous said...

Boy, do I feel like a dozy dolt. I thought you pulled the previous picture from an ant-drug campaign.

rank sophist said...

This is the first time that I hear someone say that its all a big misunderstanding. From all that I've read on both sides (East and West), they seem to be quite certain in their understanding and criticism of the doctrine of the other side.

I've done a fair amount of reading on the subject myself, trying to see if there was a way to reconcile Eastern Orthodoxy with Thomism. My conclusion has been "yes", because the disagreements are in large part thanks to misunderstandings. Even the essence-energies distinction of Palamism has a (more subtle) counterpart in Thomism.

Also, from what I undersatnd, (I stand to correction in this) Contra Errores Graecorum deals mainly with the filioque clause, papal primacy, unleaven bread in the Eucharist and purgatory, not the scholastic approach to theology.

Yes, this is true. However, Aquinas's goal was to show that translation errors and so forth had caused miscommunication, and that the two churches were largely the same. I was just using it as an example of the misunderstandings between the groups. The biggest, nastiest misunderstandings were thanks to Barlaam and the hesychasm, which happened later on.

The book you mentioned takes an interesting position, will certainly check it out.

Glad I was helpful. I'm going to stop with the off-topic posts now, though.

Glenn said...

Speaking of equivocation (12:13 AM: "But here [so-and-so] commits a fallacy of equivocation"), I shall present anon Impeccable Proof That A Plant Is One Kind Of Sentient Being.

In order that the presentation may indeed be anon (as opposed to, say, immediate), I first would like to mention that the claim that plants not only are sentient but are sentient in the way that humans are sentient, seems to bear some resemblance to the claim that simulated hurricanes not only are real but are real in the way that real hurricanes are real.

The trick, of course, has not to do with considering things as they may be in and of themselves, but with employing terminology in such a way as to render equivalent that which is not (see, e.g., Why a simulated hurricane might be thought of as a real hurricane).

Now, as had been previously stated would be presented anon:

Impeccable Proof That A Plant Is One Kind Of Sentient Being

1. One kind of sentient being is a human being.

2. A human being may be employed as an operative of the CIA.

3. A CIA operative may be stationed in a given location as a spy or observer.

4. A person stationed in a given location as a spy or observer is a plant.

5. Ergo--and indubitably--a plant is one kind of sentient being.

Josh said...

Glenn lulz

Gene Callahan said...

"First of all, you are putting words in my mouth. I never said that the point about qualia was the only thing you misunderstood."

Huh? You *did* say I misunderstood that. I said I didn't. It's *you* now who is, for the first time, introducing some claim about the *only* thing!

"Second, if you don't claim to be an expert on what the A-T view about plant life actually is, then maybe you shouldn't be making these peremptory statements about how the A-T view about plant life has been refuted."

A theory that says that bacteria are animals and fungi are plants is, I am sorry to say, *not* a theory that I am going to be spending a lot of time studying. I am also not going to devote much time to alchemy this year. I will still attempt to tell my friends it is not something they should endorse, despite my not having devoted much study to it.

Gene Callahan said...

@rank sophist: "On the contrary, Oderberg takes great pains to explain why locomotion and sentience are necessarily connected, both in terms of evolutionary biology and metaphysics."

Well, but *your quote* did not go to great pains to explain this, so *your quote* was merely begging the question. I can only comment on what you actually write, not what is in your memory!

Anonymous said...

Gene Callahan said...A theory that says that bacteria are animals and fungi are plants is, I am sorry to say, *not* a theory that I am going to be spending a lot of time studying.

Oh, you mean you only study theories that you "like"? Personally, I want to study theories that are *true*. Different strokes for different folks, I guess.

I am also not going to devote much time to alchemy this year. I will still attempt to tell my friends it is not something they should endorse, despite my not having devoted much study to it.

That would be pretty irresponsible of you. Unless of course you have different but equally adequate reasons to support such a claim.

rank sophist said...

Plants, as Linnaeus and other biologists observed, have none of these animal powers, only vegatative ones. We do not observe plants exercising such powers. This is a good a posteriori argument for the distinction between plants and animals, but there is a metaphysical one behind it. In the case of plants, it is a modus tollens. Given that the environment of all living things is a constantly changing mix of beneficial and harmful stimuli - one of the factors regularly appealed to by evolutionary biologists to explain phenomena such as extinctions and the non-ubiquity of perfect adaptations - sentience should guarantee the existence of locomotion, in order that an organism should be equipped to move itself towards sources of beneficial sensations and away from sources of harmful ones. Plants do not have such locomotion. Therefore, they cannot have sentience either. To put the argument more bluntly: what is the point of nature's equipping an organism with sentience but not with the means of moving towards the good stimuli and escaping the bad ones, especially the ones whose sources may destroy the organism?

In the case of animals, the argument is a modus ponens of the reverse entailment. Locomotion should guarantee the existence of a power that gives locomotion its point. What point would there be to an organism's being able to move itself from place to place if it had no power that made such movement useful? Again, this would be a potentially destructive situation for the organism, since if it could move without sensing what it had moved to, it could move to a noxious environment and perhaps be destroyed. Yet animals can move themselves from place to place. So they must have a power that makes this useful rather than harmful, and that is sentience - the ability to sense the distinction between good and bad environments.

This sort of argument might be looked at as an inference to the best explanation, and if so it is a strong one. But given the way the world inherently is - a flux of changing environmental conditions - there would seem to be a metaphysical connection between sentience and locomotion: the nature of a non-moving organism requires that it lack a power whose possession in the absence of locomotion would would certainly destroy such an organism. And the nature of a moving organism requires that it possess a power without which locomotion would be harmful at best, destructive at worst. An objector might retort that the argument presupposes the idea that nature does nothing in vain, which is supposedly folk biology or metaphysical obscurantism. The objector might appeal to Stephen Jay Gould and Richard Lewontin's concept of a spandrel, a non-adaptive by-product of some other genuine adaptation (Gould and Lewontin 1979). But sensation without locomotion, or locomotion without sensation, would not merely be non-adaptive; they would be at least maladaptive and at worst contribute to the death of the organism. It is hard to see how biologists could explain (1) why, if the necessary conjunction of sentience and locomotion is in fact absent, any plant or animal is alive right now or ever was, and (2) how and why an organism could ever be or get into such a state of having one power but not the other.


He mounts even more significant arguments after this, but I'm sure you can understand that copying so much text manually is a tremendous pain.

Edward Feser said...

Gene,

You complained earlier that it was not "playing fair" for me now to accuse you of not understanding what A-T means by "vegetative" and "locomotion" when I had originally accused you of not understanding that A-T regards "sentience" as implying qualia. But the complaint of unfairness makes sense only if I was somehow shifting my ground -- that is, if I had originally claimed that you had only misunderstood the latter point and was now suddenly and arbitrarily accusing you of misunderstanding the other points too. Well, I was not shifting my ground. I never claimed in the first place that the point about qualia was the only one you misunderstood. That's what I was saying in my remarks above.

But why do you keep hammering on this trivial stuff instead of engaging the arguments I gave? Indeed, you do worse than failing to engage them -- you seem not even to have read them when you write:

A theory that says that bacteria are animals and fungi are plants is, I am sorry to say, *not* a theory that I am going to be spending a lot of time studying.

I have already explained that when A-T writers classify fungi as "vegetative," they are not claiming that they are "plants" in the sense in which modern biology speaks of plants, but are using the term "vegetative" in a technical sense. And a similar point applies to the question of whether bacteria are "animals." "Animal," like "vegetative," has a technical metaphysical sense in A-T, so that A-T is not in conflict with the way modern biology classifies bacteria (any more than the specialized use of "species" and "genus" in logic is in conflict with modern biology).

And the stuff about "alchemy" is really pathetic and unworthy of you. If you're going to descend to cheap rhetoric, at least have the decency to address the arguments of the other side in the course of doing so.

Edward Feser said...

Gene,

To see how you are coming across, consider a critic of the free market who said:

A theory that says that we should let children, widows, the disabled, et al. starve in the streets is, I am sorry to say, *not* a theory that I am going to be spending a lot of time studying. I am also not going to devote much time to alchemy this year. I will still attempt to tell my friends it is not something they should endorse, despite my not having devoted much study to it.

Or consider a critic of idealism who said:

A theory that says that my thermostat is as conscious as I am is, I am sorry to say, *not* a theory that I am going to be spending a lot of time studying. I am also not going to devote much time to alchemy this year. I will still attempt to tell my friends it is not something they should endorse, despite my not having devoted much study to it.

You would, quite rightly, regard such remarks as intellectually frivolous. Well, your remarks are no better.

Daniel Smith said...

Ed: ...the lack of variability in response to stimuli. You have said nothing in reply to those reasons.

Amen to that.

He didn't really address my question (in the first thread) about whether there was evidence that a plant could choose to respond differently to identical stimuli.

He skirted the question by disputing my wording (he objected to my speaking of "two identical plants" but I also gave the example of "the same plant, under identical conditions, subjected to the same stimulus".)

I would like to hear him answer the question scientifically: Is there evidence that the same plant, under identical conditions, when subjected to identical stimulus, will choose to react differently sometimes?

Glenn said...

Dr. Feser above:

- - - - -

Gene Callahan responds to my recent criticisms of his view [informed by a report of research conducted by Dr. Monica Gagliano] that plants are sentient... Recall that I had noted three reasons Aristotelians deny that any plants possess conscious awareness... 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..., Gene writes:

...[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...

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."...

- - - - -

Not that it matters now, but Dr. Monica Gagliano herself asserts that plants "can't move".

Alastair F. Paisley said...

@ Edward Feser

> The first is that plants lack the specialized sense organs we find in animals. <

Darwin proposed that the "radicle" acts like a brain in plants.

Charles Darwin studied the movement of plants and in 1880 published a book The Power of Movement in Plants. In the book he concludes:

It is hardly an exaggeration to say that the tip of the radicle thus endowed [..] acts like the brain of one of the lower animals; the brain being situated within the anterior end of the body, receiving impressions from the sense-organs, and directing the several movements


(source: Wikipedia: Plant intelligence)

Also, experiments have been conducted that seem to indicate that every plant has a nervous system.

Indian scientist Sir Jagdish Chandra Bose began to conduct experiments on plants in the year 1900. He found that every plant and every part of a plant appeared to have a sensitive nervous system and responded to shock by a spasm just as an animal muscle does.[28][29]

(source: Wikipedia: Plant intelligence)

> The second is that plants lack the variability of response to stimuli that animals possess. <

There is empirical evidence that bacteria exhibit this trait.

"Bacteria Are More Capable of Complex Decision-Making Than Thought"

Moreover, there is empirical evidence that even an electron has this capacity.

"Even an electron has at least a rudimentary mental pole, respresented mathematically by the quantum potential."

(source: pg. 387 "The Undivided Universe: An Ontological Interpretation of Quantum Theory" by David Bohm and B.J. Hiley)

The bottom line is that you have the same problem as the materialist - namely, explaining why consciousness was naturally selected and also explaining how sentient matter arises out of insentient matter.

Crude said...

Ed,

I was wondering if you intend to comment on the recent Leah Libresco conversion, and some of the arguments brewing related to that? Since she apparently made her conversion as a result of her belief in virtue ethics, which in turn goes back to natures and Aristotle and, etc.

I'm thinking particularly of here, where an 'atheist virtue ethicist' tries to argue Leah out of catholicism. He seems to be making what I think you've noted before is a common modern mistake - I think his "natures" cash out as "functions", etc.

S.L. Brock said...

Regarding the connection between sentience and locomotion in Aristotelian thought, it might be worth noting that Aquinas, at least, thinks there can be, and are, sentient beings that lack the power of locomotion. He cites oysters. See Summa theologiae, I, q. 78, a. 1.