Saturday, August 19, 2006

Stimulus Meaning, Ducks, and Rabbits

this was a paper i was stressed over last week. the whole time writing it, something didn't feel right, but i couldn't figure out what it was... or maybe i was to a point where i didn't want to know what it was because i couldn't go back and do another topic. so for any of you quine fans out there, throw me some criticisms.

Stimulus Meaning, Ducks, and Rabbits

In the second chapter of Word and Object,[1] Willard Quine argues that through a thought experiment of radical translation, meaning can be understood as a synonomy of stimululus meanings. This occurs when different terms are utilized by subjects to describe the same experience of stimuli. In this paper, I will argue that Quine’s notion of stimulus meaning is problematic when an image, such as Wittgenstein’s duck-rabbit, is used that may prompt very different stimulatory responses. I will also counter the objections that may arise to this criticism.

Following his example of a linguist trying to confirm a native’s exclamation of ‘Gavagai’ to a nearby scurrying rabbit, Quine points out that “[i]t is important to think of what prompts the native’s assent to ‘Gavagai?’ as stimulations and not rabbits.”[2] This is primarily because our experience and interaction with “external things” does not occur directly with those things, but is rather the subjectively “only through impacts at our nerve endings.”[3] Rather than ‘directly’ experiencing the table and laptop computer in front of me, my subjective experience is rather merely stimulations of nerve endings in my body. I experience the table and laptop in front of me as a combination of certain stimulations of nerve endings in the skin of my fingers, hands, elbows; as well as a pattern of stimulated cornea in my eyes as light is reflected off the table and laptop, through the lenses of my eyes, and into the light-responsive nerve endings deep within my eye sockets.

That we are not directly experiencing the external things is easily recognized when it is noted that the stimulation which led to the native’s exclamation of ‘Gavagai’ “remain[s] the same though the rabbit be supplanted by a counterfeit.” A native may exclaim ‘Gavagai!’ or assent to ‘Gavagai?’ if the object in question was not a rabbit at all, but a misshaped German chocolate cake with coconut frosting, which just happened to result in the same reflected light and coordination of stimulated nerves that a rabbit would cause.

Quine calls these stimulations “pattern[s] of chromatic irradiation of the eye,”[4] and it is here that Quine’s notion of stimulation meaning becomes problematic. Not only does he want to say that two different external objects can create identical linguistic responses (as in the case of the native assenting to ‘Gavagai?’ to both a rabbit and a counterfeit), but Quine wants to also insist that identical stimulations will result in identical linguistic responses from the subject. Quine says:

In taking the visual stimulations as irradiation patterns we invest them with a fineness of detail beyond anything that our linguist can be called upon to check for. . . . He can reasonably conjecture that the native would be prompted to assent to ‘Gavagai’ by the microscopically same irradiations that would prompt him, the linguist, to assent to ‘Rabbit,’ even though this conjecture rests wholly on samples where the irradiations concerned can at best be hazarded merely to be pretty much alike.[5]

Quine continues to argue that when linguistic responses of two subjects are given for a particular setting for stimulation or class of stimuli (perhaps bound by “properly timed blindfoldings”), then they have the same “stimulus meaning.”[6] For example, the linguist could observe an English-speaking subject affirmatively responding to ‘Rabbit’ after having been shown a photo, and compare that to the native’s affirmative response to ‘Gavagai’ using the same photo. ‘Gavagai’ and ‘Rabbit’ would arguably have the same stimulus meaning.

The problem with Quine’s argument is that it assumes an individual subject will give the same linguistic response to indistinguishable sensory stimuli. In his Philosophical Investigations, Ludwig Wittgenstein brings up the example of Joseph Jastro’s ‘duck-rabbit’ image to discuss his notion of ‘seeing-as.’ This is an image that can be seen either as a rabbit’s head or a duck’s head.

Wittgenstein says:

I may, then, have seen the duck-rabbit simply as a picture-rabbit from the first. That is to say, if asked “What’s that?” or “What do you see here?” I should have replied: “A picture-rabbit”. . . .

I should not have answered the question “What do you see here?” by saying: “Now I am seeing it as a picture-rabbit”. I should simply have described my perception: just as if I had said “I see a red circle over there.”[7]

Wittgenstein could have just as easily responded to the question “What’s that?” with “A picture-duck.” Likewise, a native may equally respond to this image with “Gavagai!” or “Tarkot!” To bring it closer to Quine’s thought experiment, it can easily be imagined that either positive assents or negative dissents are acquired from the subjects by the linguist asking “Rabbit?”, “Duck?”, “Gavagai?”, or “Tarkot?”.

One of the first noticeable problems is that with the image of the duck-rabbit (of which there are even more detailed and ambiguous images available), the results are possible that the linguist could have ‘Duck’ and ‘Gavagai’ (or ‘Rabbit’ and ‘Tarkot’) as having the same stimulus meaning due to different responses between the English and native subjects to the exact same setting for sensory stimuli. Alternately, the linguist could have ‘Rabbit’ and ‘Gavagai’ (or ‘Duck’ and ‘Tarkot’) as having the same stimulus meaning.

The problem is two-fold. First, Wittgenstein (in response to possibly seeing it as a rabbit) notes, “If I had further been asked what it was, I should have explained by pointing to all sorts of pictures of rabbits, should perhaps have pointed to real rabbits, talked about their habits, or given an imitation of them.”[8] Similarly the native assenting to “Tarkot?” could point to pictures of ducks or real ducks. Here you have two subjects with the same sensory stimuli, using two different responses, but being attributed of having the same stimulus meaning in their responses, even though they meant two very different things (as indicated by possibly pointing to other rabbits and ducks).

Second, this problem is just as easily witnessed without the difficulties associated with multiple languages. It could be quickly shown or imagined that two English speakers given the same image and sensory stimuli (or pattern of chromatic irradiation of the eye) could respond differently; with one affirming a ‘Rabbit’ response and the other affirming a ‘Duck’ response. Here you would have ‘Rabbit’ and ‘Duck’ as having the same stimulus meaning. This would be quickly understood by the observer and the subjects as being absurd. “Surely,” the subject might say, “I did not mean the same thing as ‘Duck’ when I said ‘Rabbit’!”

This problem is further problematized by the possibility of the same individual subject affirmatively responding to the duck-rabbit image as ‘Rabbit’ at one moment and ‘Duck’ at another moment. While the pattern of chromatic irradiation has remained exactly the same, the subject has given two very different stimulus meaning responses. However, according to Quine’s notion of stimulus meaning, ‘Duck’ and ‘Rabbit’ would both have the same stimulus meaning.

One could argue that the different responses to the duck-rabbit are results from the boundaries of the sensory stimuli being too bounded, when they are in fact much more broad and encompass more stimuli than what has been considered. Quine acknowledges that other factors can affect how a subject may respond. This is because “an informant’s assent or dissent. . . can depend excessively on prior collateral information as a supplement to the present prompting stimulus.”[9] This need not only apply to multiple subjects because a “stimulus meaning is the stimulus meaning of a sentence for a speaker at a date; for we must allow our speaker to change his ways.”[10] Collateral information or additional stimuli can greatly affect the stimulatory response, and thus stimulatory meaning of a sentence, both between subjects, and between a single subject at two different points in time.

Even Wittgenstein acknowledges the effect that extra stimuli can have in affecting the response offered by the subject:

I see two pictures, with the duck-rabbit surrounded by rabbits in one, by ducks in the other. I do not notice that they are the same. Does it follow from this that I see something different in the two cases? It gives us a reason for using this expression here.

“I see it quite differently, I should have never have recognized it!” Now, that is an exclamation. And there is justification for it.[11]

Here Wittgenstein illustrates how additional collateral information (in this case, extra images of ducks or rabbits) can affect how the stimuli is understood and responded to.

While this may account for some of the differing responses to the duck-rabbit image, it still does not account for all of them. Even after all collateral and sensory stimulation has been accounted for, there can still be variations of responses to the duck-rabbit, even by the same subject. For example, without any additional or changing sensory stimuli, a subject may look at the duck-rabbit image, affirm ‘Rabbit’ in response to seeing it as a rabbit, and then suddenly dissent from that claim and affirm ‘Duck’ in response to seeing it as a duck – without the subject ever moving her eyes away from the image. This transition from one to the other can continue endlessly without any conclusive decision as to which response should be accepted for an understanding of stimulus meaning.

One could also argue that the possibility for different ‘Duck’ and “Rabbit’ responses should be understood as the terms conjoining to make up a single term or sentence. Or in other words, that ‘Duck’ and “Rabbit’ should not be held exclusive to the other, but should be understood together as a larger sentence: ‘‘Duck’ and ‘Rabbit’’. There are two problems with this approach. The first is that the duck-rabbit image is not seen simultaneously as a duck and a rabbit, but is rather seen as one, then the other alternatingly.[12] The second problem is that even if one were to take an approach of utilizing an extended amount of time so that the stimulatory response was a sentence like, “It is a rabbit at one moment and a duck at another,” this would also fail because it is possible that a subject might not ever see it as both. One can easily imagine a person only seeing it and responding affirmatively ‘Rabbit’ or ‘Duck,’ but not both. This would then fall to the original argument that two very different stimulatory response sentences were accepting as having the same stimulus meaning. Like incompatibility of the different ‘Duck’ and ‘Rabbit’ responses, the responses ‘Duck and Rabbit’ and ‘Only duck’ are likewise incompatible.

In conclusion, Quine’s notion of stimulus meaning is problematic because a single image may provide a single set of sensory stimulation to a subject or subjects, and yet prompt very different stimulatory responses. This results in the assertion that these very different responses are said to have the same stimulus meaning. This is true for subjects with different languages, subjects using the same language, and a single subject speaking only one language.

[1] Willard Van Orman Quine, Word and Object (Cambridge: MIT Press, 1960).

[2] Ibid., 31.

[3] Ibid., 2.

[4] Ibid., 31.

[5] Ibid.

[6] Ibid., 32-33.

[7] Ludwig Wittgenstein, Philosophical Investigations, trans. G.E.M. Anscombe (New York: Macmillan Publishing Co., Inc., 1958), 194e-195e.

[8] Ibid., 194e.

[9] Quine, Word and Object, 37.

[10] Ibid., 33.

[11] Wittgenstein, Philosophical Investigations, 195e.

[12] I realize that the claim could be made that it is possible that someone could see both a rabbit and duck simultaneously. However, because I have yet to see anyone claim this, nor can I imagine how it might be possibly seen as both simultaneously, I have not acknowledged it as a possible criticism. Furthermore, this claim is still problematic because of the second response to this criticism.


  1. I like ducks and rabbits.

  2. I like my duck medium rare with a nice lingdonberry sauce and a fruity zinfindal wine.

  3. Don't forget Quine support the idea of Physical World, but not in the same meaning of Einstein. W.V. Quine is speaking about cosmic world, meaning, the touchable world. He said there are this world which is imposible to be translated where he hold the inscrutability of reference. Quine overtook the Mind-Body dualistic approach by Descartes.


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