This essay asks the following question: Are insects and plants organic machines? It does so in the contexts of Robert Kirk’s semi-mechanistic position and Philip Goff’s panpsychism.
The British philosopher Robert Kirk (as found in his paper ‘How is Consciousness Possible?’) uses the term “pure stimulus-response system” to refer to the behaviour of a fruit fly. The panpsychist Philip Goff, on the other hand, doesn’t even see the behaviour of plants in such mechanistic terms. Indeed, his position on trees particularly seems to be obviously (at least to me) anthropomorphic.
The position of the mathematical physicist Roger Penrose (on the complex behaviour of paramecium) is also discussed. Whether Penrose’s position is another example of panpsychism is open to debate. (Penrose himself throws various spanners into the works.)
Weighing Machines and Plants
Robert Kirk argues that a weighing machine “can do nothing with the information” it receives from the inputs — i.e., things placed on the scale. However, the machine does react differentially to different weights. Thus, “it gives us information we can use”. Yet, more relevantly, this machine “cannot assess its situation, and it cannot initiate or control its behaviour”. It is, according to Kirk, a “pure stimulus-response system”.
Is a weighing machine pretty much like a plant in these respects?
The panpsychist philosopher Philip Goff thinks not.
Although a plant can be seen as a “pure stimulus-response system” (even if biological), Goff chooses to see things differently. He writes:
“[W]e now know that plants communicate, learn and remember. I can see no reason other than anthropic prejudice not to ascribe to them a conscious life of their own.”
It’s important to note here that Goff doesn’t use the words “communicate”, “learn” and “remember” metaphorically (or loosely). He really believes that plants have a “conscious life of their own”. Yet plants may be similar to weighing machines in at least the respects so far discussed.
In Kirk’s own terms: does a plant “asses its situation” or “initiate or control its behaviour”? A plant certainly behaves differentially to different external conditions — as does a weighing machine. But does it initiate or control its behaviour? Yes, but only in the strict and limited sense that every plant of the same species does so in the same way. And if every plant responds in the same way to the same external conditions (or stimuli), then is it correct to say that it initiates or controls its behaviour? Semantically, or in terms of stipulation, perhaps it is.
Similarly, does a plant “asses its situation”?
Again, yes, but only in the same way that every other plant of the same species does so. So, in identical conditions or with identical stimuli, all plants of a given species (to use scare quotes) “behave” or “respond” in the same way. However, if there are any slight differences, then that will be because there are slight differences in the environment which haven’t necessarily been noted.
Computers, garden sensors, piano strings, weighing machines, etc. respond to stimuli is specific ways. So too do plants.
So does biology make a difference here?
Next comes the possibility of interpreting the behaviour of plants in human-like terms. And that’s precisely what Philip Goff does. He writes:
“The mycorrhiza structures [between tree roots and fungi] allow for a complex system of egalitarian redistribution.”
We’ve already seen that Goff believes that plants “communicate, learn and remember”. And it can be concluded that all his interpretations must surely be based on the physical behaviour of plants, not on any access to their (to use Rudy Rucker’s terms) “inner lives”.
Monica Gagliano on Pea Plants
Philip Goff then cites an experiment by Professor Monica Gagliano. He writes:
“In order to set up a similar scenario with her pea seedlings, Gagliano put a pea plant at one end of a Y-shaped tube, so that it could grow in either of two directions, left or right. In one direction was the seedling’s ‘food,’ in the form of blue light. In normal circumstances, the pea seedlings will instinctively grow toward where the light was last present. However, Gagliano tested whether the seedlings could associate the sound of a computer fan with the presence of the blue light, by repeatedly placing the noise at the end of the tube where the blue light was located. Upon repeated trials, she found that just as Pavlov’s dogs had salivated at the sound of the bell, so the pea seedlings grew toward the noise of the computer fan. In both cases, a sound that was initially meaningless to the organisms had come to represent dinnertime.”
Plants don’t need to hear sounds or see light. Despite that, they can still be causally affected by both sound and light.
More particularly, isn’t it the case that the seedlings in this experiment would have also been causally affected by the sound of a computer fan? So rather than the seedlings “associat[ing] the sound of a computer fan with the presence of the blue light”, they might have simply been causally changed by the sound of the fan instead of the blue light.
So where does Goff’s supposition of association come from?
In more detail. Light is a wave and sound is also a wave — both with very determinate physical natures. Thus, the seedlings might have moved toward the sounds of the computer fan because — in many respects — they were like the waves of blue light. This means that the sound waves of the fan must have causally impacted on the seedlings, just as the light waves had done so previously.
So there’s no (immediate?) need to talk of “meaning”, “association”, “value”, etc. — as both Goff and Gagliano do.
To repeat: might the sound waves (from the fan) have had a similar causal impact on the seedlings as the waves of (blue) light had previously done?
[See the BBC’s ‘Light and sound — reflection and refraction’.]
Goff must also know that even non-biological (i.e., artificial) objects display “movement” in response to their environments.
Take computers and other electronic devices.
Such entities change or move in (causal) response to that which is external to them. Yet, oddly enough, Goff himself doesn’t believe that computers are — or even can be — conscious. Indeed, he spends some time in Galileo’s Error saying so — if only implicitly. (At the very least, Goff seems to be sympathetic to John Searle’s well-known Chinese Room argument.)
Despite focussing on Goff’s panpsychist position on Gagliano’s experiment, it seems that Gagliano herself is a panpsychist… of sorts. (Perhaps that’s why Goff noted her experiments in the first place.)
For example, Gagliano states (as quoted by Goff) the following:
“‘If the plant is imagining its dinnertime arriving, based on a simple fan that is associated to the light, then who is doing the imagining? Who is thinking here?’”
It’s clear (even if only from Goff’s own words in Galileo’s Error) that Gagliano already had reasons to believe — or hope — that she’d find the results she found. (See Fudge Factor and Experimenter-Expectancy Effect.) After all, according to Goff himself, she actually set up a “similar scenario” to Ivan Pavlov’s well-known experiments on dogs in order to see if her pea seedlings would behave in the same — or in a similar — manner to dogs.
Roger Penrose on Paramecium
In a similar (though far from identical) vein are the words of the mathematical physicist Roger Penrose. Of all animals, Penrose actually cites the case of the single-celled paramecium. He writes:
“For she [a paramecium] swims about her pod with her numerous tiny hairlike legs — the cilia — darting in the direction of bacterial food which she senses using a variety of mechanisms, or retreating at the prospect of danger, ready to swim off in another direction. She can also negotiate obstructions by swimming around them. Moreover, she can apparently even learn from her past experiences [].”
One can detect certain anthropomorphic words and phrases here too.
For example, “retreating at the prospect of danger”, “negotiate obstructions, and “learn from her past experiences”. That said, these words are probably (or possibly) used because it will have been very hard to think of any alternatives.
In any case, can’t the paramecium “darting in the direction of bacterial food”, “retreating at the prospect of danger”, “negotiat[ing] obstructions” and “learning from her past experiences” all be explained mechanistically? (Penrose himself uses the words “which [the paramecium] senses using a variety of mechanisms” about a paramecium.)
Penrose then discusses the paramecium in the specific context of panpsychism, as well as in the context of the possible lack of importance of neurons when it comes to consciousness. He writes:
“If we are to believe that neurons are the only things that control the sophisticated actions of animals, then the humble paramecium presents us with a profound problem.”
Finally, Penrose asks his readers a question:
“How is all this achieved by an animal without a single neuron or synapse? Indeed, being but a single cell, and not being a neuron herself, she has no place to accommodate such accessories.”
Penrose answers his own question by focussing on the relevance of cytoskeletons and microtubules. He writes:
“It is the cytoskeleton’s role as the cell’s ‘nervous system’ that will have the main importance for us here. For our own neurons are themselves single cells, and each neuron has its own cytoskeleton!”
More relevantly:
“Does this mean that there is a sense in which each individual neuron might itself have something akin to is own ‘personal nervous system’?”
Yet Penrose does indeed qualify his stance with the following words:
“[I]t must also be the case that the detailed neural organization of the brain is fundamentally involved in governing what form that consciousness must take. Moreover, if that organization were not important, then our livers would evoke as much consciousness as do our brains.”
Despite all the above, Penrose is at his most (well) panpsychist when he concludes:
“[S]uch (putative) non-computational processes [i.e., in the brain] would also have to be inherent in the action of inanimate matter, since living human brains are ultimately composed of the same material, satisfying the same physical laws, as are the inanimate objects of the universe.”
Robert Kirk on the Fruit Fly
Let’s now move up a few evolutionary levels and tackle the fruit fly.
Robert Kirk writes:
“Much of the behaviour of many insects seems to conform to that pure stimulus-response pattern.”
However, Kirk immediately qualifies (or questions) this position when he tells us that “since even the fruit-fly is able to find its way home, it is capable of learning”. Thus, to Kirk, a fruit fly “is not a pure stimulus-response system in my sense”.
Some readers may wondering if being “able to find its way home” stops a fruit fly from being a stimulus-response system. After all, even its reactions to new environments may still be “hard-wired”. In other words, different environments elicit differential responses which are also machine-like.
For example, roses “act” differentially in different environments. More specifically and obviously, a plant may flower more in one environment than a plant of the same age and species in a different environment.
Kirk also writes:
“[F]lies are hardwired so that if their feet break contact with a surface, their wings are automatically caused to buzz; and if their feet make contact with a surface, their wings are automatically caused to stop buzzing. Similarly, if their feet are in contact with a surface and that surface emits certain chemicals, the fly’s mouth-parts are caused to go into action. (With luck, the surface will be decaying meat.)”
It can be asked how the experts on flies actually know all this. More relevantly, how does Kirk himself know that the fruit fly’s responses are automatic? Even though there are — obviously — hardwired elements to both a fruit fly’s body and its responses, there still may be a remainder which takes it beyond responding automatically. That said, it can be strongly doubted that this is, in fact, the case.
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