The most common objection against wave theory, which I call the spatial misrepresentation objection, concerns the spatial representation of sounds.
S1. Compression waves propagate from their sources in the sur-rounding medium.
S2. We never hear sounds as moving in the way compression waves propagate.
S3. Therefore, sounds are not compression waves.
(i.e. Wave theory is false)
S1 should be an indisputable scientific fact. S2 also seems to be quite plau-sible. I have never heard anything as moving like a giant balloon inflating rapidly from a sound source, or like an arrow flying from a sound source to me.
It is obvious that the veridicality of our auditory experiences of sounds is assumed, and this is, as I said previously, a questionable assumption. Nonetheless, I will accept it for the moment and see if we can satisfactorily respond to the objec-tion.
If wave theorists accept both premises, then they can only challenge the in-ference. Let us consider two possible ways to do so.
6.3.1 First Response: Not Hearing Sounds
There is one radical response, that is, we deny that we hear sounds. If we do not hear sounds, then, of course, we do not hear them as propagating in the way compression waves do. But then S2 will become irrelevant to what sounds are, and hence S3 does not follow.
This idea may seem too radical, but perhaps wave theorists may motivate it by considering a parallel argument against the identity between light and electro-magnetic waves:
L1. Electromagnetic waves propagate from light sources to the surroundings.
L2. We never see light as moving in the way electromagnetic waves propagate.
L3. Therefore, light is not electromagnetic waves.
To be consistent, wave theorists should reject this argument, and I believe many people would be reluctant to accept L3.
In this case, if we challenge the inference by denying that we see light, the consequence does not seem to be very devastating. Hilbert (2005, pp. 150-151), for instance, holds on phenomenological grounds that we see how an object is illumi-nated but not the illumination itself. Perhaps all we see are objects including light sources and reflective objects. Such objects might look bright, but we do not see light in addition to seeing them. Light as electromagnetic waves can cause visual experiences, but it is not itself experienced.
So, wave theorists might suggest that all we hear are objects such as sound sources. Sounds as compression waves are causes of auditory experiences, but they are not themselves experienced.
Is there any other reason for wave theorists to deny that sounds are experi-enced? The eliminativism of Young (2016) is one suggestion. Recall that the weaker interpretation of his view is to deny the role of sounds merely in auditory perception. Accordingly, no matter what sounds are, we need not to incur them in explaining our auditory experiences. Therefore, we should simplify our theory of auditory perception by denying that sounds are experienced.
Young’s view is based on a theoretical consideration, that is, the simplicity of his theory of auditory experience. It thus relies on the presumption that his theory is correct. Strictly speaking, wave theory is consistent with Young’s view, since it is possible that sounds are compression waves but do not figure in our auditory experiences. Nonetheless, wave theorists probably would not want to add a further commitment to this theory of auditory experience.
Besides, I do not think that a description of auditory experiences can be complete without mentioning compression waves. As I have argued in §4.2.1, Young’s sound-less account cannot explain some aspect of our auditory
experiences. The example I used is our echo experiences, a more detailed discussion of which can be found in §5.2.6 in connection with distal event theories in general.
Here is a quick review. If wave theory is true, not hearing sounds means not hearing compression waves. However, when I hear an echo one second after I hear an explosion, the most reasonable thing to say is that I hear the delay between the arrival of the primary wave and the arrival of the reflected wave. This experience is impossible unless it can represent compression waves. Therefore, wave theorists cannot accept a sound-less account of our echo experiences, and hence they cannot employ the first response that we do not hear sounds.
6.3.2 Second Response: Not Hearing the Propagation of Sounds
The more plausible way to challenge the inference in the spatial misrepre-sentation objection is to say that although sounds as compression waves are expe-rienced, we fail to hear their propagation. Let us consider this argument:
W1. Water flows in the river.
W2. If we look at the river from afar, we cannot see anything as moving in the way water flows.
W3. Therefore, if we look at the river from afar, we cannot see the water in the river.
This argument obviously fails because it is more reasonable to say that we simply fail to see the flow of the water. Although this argument is not exactly par-allel to the spatial misrepresentation objection, it seems the latter can also only war-rant the conclusion that we fail to hear the propagation of compression waves.
I think this is the best response to the spatial misrepresentation objection.
Wave theorists should hold that whatever it is like to hear compression waves, it is not to hear them as propagating. This negative claim immediately prompts us to ask for a positive characterisation of what it is like to hear sounds. Indeed, the lack of such a positive characterisation leaves open a way to strengthen the spatial misrep-resentation objection, which shall be examined before we move on.
6.3.3 Not Hearing Sounds as Distally Located
Here is the strengthened version of the spatial misrepresentation objection:
S1. Compression waves propagate from sound sources to the surroundings.
S2′. We hear sounds as located at where their sources are.
S3. Therefore, sounds are not compression waves.
S2′ positively asserts what it is like to hear sounds, that is, to hear them as located at where their sources are. My response to this strengthened objection is that S2′ is an inaccurate characterisation of our auditory experiences.
There are two possible interpretations of S2′. The first interpretation says that we hear a sound as sharing the same location with its source. We hear the rela-tion of co-locarela-tion. To do so, both the sound and its source should appear in my auditory experience, and they need to appear at the same location. However, this does not seem to be phenomenologically accurate.
Suppose I close my eyes and tap the table. This event causes me to have an auditory experience. Within this experience, there appears to be only one individual at a certain distance away from me. According to the identification problem of au-ditory objects, it may be the event of my tapping the table or the sound of this event.
However, whatever the auditory object is, there does not appear to be two things sharing the same location.
The second interpretation says that we simply hear a sound as located at a certain location. As a matter of fact, this location is the location of the sound source, but this fact does not enter the content of my auditory experience. Instead, we learn it in some other ways.
This interpretation fits better with the phenomenal character of my experi-ence, as it requires only one thing to appear in my experiexperi-ence, namely, the sound.
But then it seems we have changed the question of what it is like to hear a sound to the question of what it is like to hear a sound source. If only one thing appears in my experience, and it is a sound, then it seems sound sources are not experienced.
However, in Chapter 2, we have seen no good reason to think that that thing we hear is not the sound source itself, and hence this does not show that what we hear is a sound rather than the sound source.
Since the two interpretations of S2′ are both implausible, we can reject the strengthened objection by rejecting S2′. In contrast, S2 in the original objection
seems to be a more accurate characterisation of our auditory phenomenology. That said, we might wonder why S2′ would seem to be plausible for the opponents of wave theory. The main reason, I suppose, is that our auditory experiences do repre-sent some entities as located at where the sound sources are. If S2′ is implausible, then wave theorists should tell us what those entities are. The answer is simple:
those are the sound sources themselves, and our auditory experiences correctly rep-resent them as being at where they are. This answer, of course, leaves unexplained what it is like to hear sounds. More specifically, it says nothing about whether and how sounds are represented spatially. I return to this issue in §6.6.