Professor Michael Egnor is not only an accomplished neurosurgeon, but also an articulate exponent of Aristotelian philosophy. In his latest article, however, he makes a fantastic claim which is foreign to Aristotle’s thinking: he asserts that whenever you perceive a distant object, your perception of that object occurs outside your body, rather than inside it. In Egnor’s own words:
When you perceive music from your radio, your perception of the music occurs at your radio. When you perceive a tree in your yard, your perception of the tree occurs at the tree. When you perceive the moon, your perception of the moon occurs at the moon. Perceptions occur at the object perceived, regardless of distance, regardless of location. It seems bizarre, but it is logically sound and, when you think it out a bit, it is plainly true.
(Do Perceptions Happen in Your Brain?, Evolution News and Views, December 1, 2015.)
My perception of the moon occurs at the moon? Something sounds very funny here. I should add that since non-human animals, such as wolves, are also capable of perceiving the moon, Egnor must presumably hold that they, too, have extra-bodily perceptions. Bizarre.
Now, it is very easy to show that this account of perception simply cannot be right. First of all, perception is a bodily event, as Egnor’s own illustrations demonstrate. To cite a few examples from his article: you see a tree, hear music and feel a pinprick. Egnor himself acknowledges: “Perception is a wholly material thing — it does have location.” He also remarks that “a subject perceives a sensory stimulus.” In other words, it is you who perceives. Since perception is a material event of which you are the subject, it must be an event involving your body.
Second, regardless of whether your perceptions are (a) actions performed by your body when it encounters external objects, or (b) passive experiences which are undergone by your body when it is affected by those objects, it is impossible for your perceptions to be located at some point which is separate from your body. Your bodily actions cannot be separated from your body, since they originate from within it. Likewise, your bodily experiences necessarily occur within your body. Either way, then, we are forced to conclude that your perceptions are events which may occur either at the surface of your body, or alternatively, inside your body – but never separately from it.
Hence it is nonsensical to claim that when you see the moon, your perception occurs at the moon, or that when you perceive music coming from your radio, your perception occurs at the radio.
Now, if Professor Egnor had contented himself with asserting that the objects of your perceptions are located outside your body, I would have been in perfect agreement with him. But when he claims that the perceptions themselves are located outside the body, then I can only reply: “I don’t know what you mean.”
Do the findings of neurophysiology support Egnor’s claim?
In his article, Professor Egnor also claims that the findings of neurophysiology buttress his account of perception:
The sensory experiments of Benjamin Libet, a neuroscientist at U.C. San Francisco in the mid 20th century, demonstrated that a subject perceives a sensory stimulus on the skin at the moment the skin is touched, before the stimulus reaches the brain and before full deliberative consciousness occurs. Libet was flabbergasted by this result and hypothesized that “the subjective timing of the experience is (automatically) referred backwards in time.” Yet Aristotle offered a much simpler and logically coherent explanation — the stimulus on the skin is perceived on the skin, not in the brain. Perception occurs at the location of the stimulus, not in the brain.
I should note at the outset that Egnor is contradicting his own argument here. For if tactile perception occurs when the skin is stimulated, then why not say that visual perception (e.g. of the moon) occurs when the eye receives light? But in that case, we shall have to locate a subject’s perception of the moon in the subject’s eye, and not (as Professor Egnor counter-intuitively claims) on the moon itself.
In any case, it is simply wrong to claim that Libet demonstrated that a subject perceives a sensory stimulus on the skin before the stimulus reaches the brain. That may have been how he interpreted his experimental findings, but other interpretations are possible. Allow me to quote from the abstract of an article by physicist S. Pockett, titled, On Subjective Back-Referral and How Long It Takes to Become Conscious of a Stimulus: A Reinterpretation of Libet’s Data (Consciousness and Cognition 11, 144–161, 2002):
The original data reported by Benjamin Libet and colleagues are reinterpreted, taking into account the facilitation which is experimentally demonstrated in the first of their series of articles. It is shown that the original data equally well or better support a quite different set of conclusions from those drawn by Libet. The new conclusions are that it takes only 80 ms (rather than 500 ms) for stimuli to come to consciousness and that “subjective back-referral of sensations in time” to the time of the stimulus does not occur (contrary to Libet’s original interpretation of his results). [Emphasis mine – VJT.]
The very most that can be said from the foregoing results is that they may lend support to the claim that perception occurs in the sensory organ, rather than the brain. And as we have seen, it is highly doubtful whether Libet’s experimental findings establish even that.
Egnor’s non-existent regress
Additionally, Professor Egnor puts forward a philosophical argument against the view that “primary qualities” [i.e. “the ordinary physical properties of an object,” – that is, “mathematically quantifiable properties such as mass, weight, dimension, location, and velocity”] “stimulate sensory organs and that perception only occurs in the brain when the secondary subjective qualities” [color, taste, feel, smell, etc.] “are conjured in the brain” (emphasis mine – VJT).
Again, I note that even if Egnor’s argument is valid and sound, all it proves is that perceptions don’t occur in the brain. It doesn’t show that perceptions are located at the objects perceived, as he claims. An alternative possibility is that they are located in the sensory organ that is affected by the stimulus – or that they are located partly in the sensory organ, and partly in the brain.
But is Egnor’s argument a sound one? Let’s have a look:
Consider this experiment. I wish to empirically demonstrate the arrival of the stimulus in my brain — the arrival that corresponds to my subjective awareness of the pain. So I hook myself up to an EEG to record my brain waves. Sure enough, when my finger is pricked, a brain wave spike occurs in my somatosensory cortex — I’ve confirmed where my conscious awareness of the secondary qualities of the pain occurs!
However, it appears that Professor Egnor has left out the last and most important step. (I say “appears” because he is, after all, a neurophysiologist; my specialty is philosophy.) The primary somatosensory cortex, which is the main sensory receptive area for the sense of touch, is located in the lateral postcentral gyrus, which is situated in the parietal lobe of the human brain. The somatosensory cortex contains a map of sensory space, known as a cortical homunculus. (The illustration above shows a cortical sensory homunculus, but there’s also a motor homunculus, relating to bodily movements.)
The point I’d like to make here is that the cerebral cortex is made up of three parts: sensory, motor, and association areas. For consciousness to occur, signals traveling to the brain have to reach the association areas. As Dr. James D. Rose explains in his widely cited paper, The Neurobehavioral Nature of Fishes and the Question of Awareness and Pain (Reviews in Fisheries Science, 10(1): 1–38, 2002):
Diverse, converging lines of evidence have shown that consciousness is a product of an activated state in a broad, distributed expanse of neocortex. Most critical are regions of “association” or homotypical cortex (Laureys et al., 1999, 2000a-c; Mountcastle, 1998), which are not specialized for sensory or motor function and which comprise the vast majority of human neocortex. In fact, activity confined to regions of sensory (heterotypical) cortex is inadequate for consciousness (Koch and Crick, 2000; Lamme and Roelfsema, 2000; Laureys et al., 2000a,b; Libet, 1997; Rees et al., 2000). (Section IV, last paragraph. Emphases mine – VJT.)
Full disclosure here: my Ph.D. philosophy thesis on animal minds cites the work of Dr. James Rose, who was very helpful in answering my scientific queries on consciousness. I would also recommend his more recent article, Can ﬁsh really feel pain? (Rose et al., Fish and Fisheries, 2014, 15 97-133), or for those wanting a less technical summary of the evidence, Dr. Rose’s primer, Do Fish Feel Pain?.
Let us return to Professor Egnor’s argument. He continues:
But there’s a problem. In the materialist paradigm, all of the conscious experience of all sensory inputs occurs in the brain, including vision. So when I observe the arrival of the stimulus on the EEG machine that corresponds to my brain wave, that stimulus blip itself is a primary quality, and it is only experienced by me when the image of the stimulus arrives in my brain — in my visual cortex. So in my experiment, when I observe my pain event in my brain, the event actually occurs in my visual cortex (corresponding to my observation of the stimulus), not in my somatosensory cortex.
Let’s assume for argument’s sake that the spike I observe in my somatosensory cortex corresponds to my conscious awareness of a painful pinprick. When I observe the arrival of the stimulus on the EEG machine, the blip is indeed a primary quality, and not a subjective experience of pain. But the blip on the EEG machine is not the same thing as the spike in my somatosensory cortex: it is an observation of that spike. What’s more, it’s an observation of the primary, or physical properties of that spike, and not the subjective qualities of pain which are associated with it. So what Professor Egnor’s argument merely shows is that if I observe my brain while experiencing a painful pinprick, then my observation of the physical properties of the conscious part of my brain will be recorded in my visual cortex.
If I were a materialist (which I’m not), I’d be underwhelmed.
Did Aristotle ever make a claim like Egnor’s?
Finally, in his article, Professor Egnor attempts to enlist the support of Aristotle (bold emphases mine – VJT):
This simple logic dates to Aristotle, who made no fundamental ontological distinction between primary and secondary qualities. He noted that perception entails the mind grasping the form (he called it the “sensible species”) of the object at the location of the object. He was a bit astonished himself at this fact. He commented that the mind is not a passive recipient of perceptions — it actively grasps the sensible properties of objects and it does so externally — at the objects perceived.…
Your mind is not bound by location. Wherever the object is that you perceive, the location of the object is where you perceive it. Your mind grasps — becomes one with — the form of the object, at the object, yet your mind remains itself. The mind, a power of the soul, is, in Aristotle’s terms, the form of forms. The mind is a form capable of grasping other forms and perceiving them, while remaining itself. It is not constrained by location.
But the only quote from Aristotle which Egnor cites is a fragmentary one: Egnor quotes him as saying that “the soul is in a way all existing things…” (De Anima iii 8). That quote says nothing about the location of perceptions. Nor does it say anything about the mind. Aristotle attributes perception to the soul, not the mind – and for a very good reason. The ability to perceive is, for Aristotle, what distinguishes animals from plants. Mind (nous), on the other hand, is what distinguishes man from the other animals.
So what did Aristotle really say about perception? The following quotes convey the tenor of his thought (bold emphases and italics mine – VJT):
Of the psychic powers above enumerated some kinds of living things, as we have said, possess all, some less than all, others one only. Those we have mentioned are the nutritive, the appetitive, the sensory, the locomotive, and the power of thinking. Plants have none but the first, the nutritive, while another order of living things [ animals – VJT] has this plus the sensory. If any order of living things has the sensory, it must also have the appetitive; for appetite is the genus of which desire, passion, and wish are the species; now all animals have one sense at least, viz. touch, and whatever has a sense has the capacity for pleasure and pain and therefore has pleasant and painful objects present to it, and wherever these are present, there is desire… What is the soul of plant, animal, man? Why the terms are related in this serial way must form the subject of later examination. But the facts are that the power of perception is never found apart from the power of self-nutrition, while – in plants – the latter is found isolated from the former. Again, no sense is found apart from that of touch, while touch is found by itself; many animals have neither sight, hearing, nor smell. Again, among living things that possess sense some have the power of locomotion, some not. Lastly, certain living beings – a small minority – possess calculation and thought, for (among mortal beings) those which possess calculation have all the other powers above mentioned, while the converse does not hold – indeed some live by imagination alone, while others have not even imagination.
(De Anima ii 3)
… Sensation depends, as we have said, on a process of movement or affection from without, for it is held to be some sort of change of quality…
…[W]e must recall that we use the word ‘perceive’ in two ways, for we say (a) that what has the power to hear or see, ‘sees’ or ‘hears’, even though it is at the moment asleep, and also (b) that what is actually seeing or hearing, ‘sees’ or ‘hears’. Hence ‘sense’ too must have two meanings, sense potential, and sense actual. Similarly ‘to be a sentient’ means either (a) to have a certain power or (b) to manifest a certain activity. To begin with, for a time, let us speak as if there were no difference between (i) being moved or affected, and (ii) being active, for movement is a kind of activity – an imperfect kind, as has elsewhere been explained. Everything that is acted upon or moved is acted upon by an agent which is actually at work.
(De Anima ii 5)
What has the power of producing sound is what has the power of setting in movement a single mass of air which is continuous from the impinging body up to the organ of hearing. The organ of hearing is physically united with air, and because it is in air, the air inside is moved concurrently with the air outside. Hence animals do not hear with all parts of their bodies, nor do all parts admit of the entrance of air; for even the part which can be moved and can sound has not air everywhere in it.
(De Anima ii 8)
The flesh plays in touch very much the same part as would be played in the other senses by an air-envelope growing round our body; had we such an envelope attached to us we should have supposed that it was by a single organ that we perceived sounds, colours, and smells, and we should have taken sight, hearing, and smell to be a single sense.
(De Anima ii 11)
(A) By a ‘sense’ is meant what has the power of receiving into itself the sensible forms of things without the matter. This must be conceived of as taking place in the way in which a piece of wax takes on the impress of a signet-ring without the iron or gold; we say that what produces the impression is a signet of bronze or gold, but its particular metallic constitution makes no difference: in a similar way the sense is affected by what is coloured or flavoured or sounding, but it is indifferent what in each case the substance is; what alone matters is what quality it has, i.e. in what ratio its constituents are combined.
(B) By ‘an organ of sense’ is meant that in which ultimately such a power is seated.
…This explains also why plants cannot perceive: …in the case of plants, the affection is an affection by form-and-matter together.
(De Anima ii 12)
…[I]n a sense even that which sees is coloured; for in each case the sense-organ is capable of receiving the sensible object without its matter. That is why even when the sensible objects are gone the sensings and imaginings continue to exist in the sense-organs.
The activity of the sensible object and that of the percipient sense is one and the same activity, and yet the distinction between their being remains. Take as illustration actual sound and actual hearing: a man may have hearing and yet not be hearing, and that which has a sound is not always sounding. But when that which can hear is actively hearing and which can sound is sounding, then the actual hearing and the actual sound are merged in one (these one might call respectively hearkening and sounding).
(De Anima iii 2)
Let us now summarize our results about soul, and repeat that the soul is in a way all existing things; for existing things are either sensible or thinkable, and knowledge is in a way what is knowable, and sensation is in a way what is sensible: in what way we must inquire.
Knowledge and sensation are divided to correspond with the realities, potential knowledge and sensation answering to potentialities, actual knowledge and sensation to actualities. Within the soul the faculties of knowledge and sensation are potentially these objects, the one what is knowable, the other what is sensible. They must be either the things themselves or their forms. The former alternative is of course impossible: it is not the stone which is present in the soul but its form.
(De Anima iii 8)
An animal is a body with soul in it: every body is tangible, i.e. perceptible by touch; hence necessarily, if an animal is to survive, its body must have tactual sensation. All the other senses, e.g. smell, sight, hearing, apprehend through media; but where there is immediate contact the animal, if it has no sensation, will be unable to avoid some things and take others, and so will find it impossible to survive. That is why taste also is a sort of touch; it is relative to nutriment, which is just tangible body; whereas sound, colour, and odour are innutritious, and further neither grow nor decay. Hence it is that taste also must be a sort of touch, because it is the sense for what is tangible and nutritious.
(De Anima iii 12)
Putting the foregoing quotes together, we arrive at the following conclusions:
1. Perception is a power of the soul which distinguishes animals from plants. (Alternatively, “perception” may denote what happens when this power is exercised.)
2. Perception involves a sensory organ being affected by the object that it senses. In other words, perception is, at least partly, a passive power, contrary to what Egnor asserts.
3. Nevertheless, this power can be actively exercised – e.g. when a person attentively listens, as opposed to merely hearing.
4. According to Aristotle, perception takes place in the sensory organ, not in the object. (For instance, he writes that “even when the sensible objects are gone the sensings and imaginings continue to exist in the sense-organs.” – De Anima iii 2.) Thus hearing takes place in the organ of hearing – i.e. the ear – rather than in the objects which create the sound that is heard.
5. In the case of perception, the sensory organ is affected in a very special way: it receives the form (i.e. the color, sound, odor, taste or touch) of the object which it senses, without receiving the object itself. This separation of the object’s form from its matter is what distinguishes sensation from mere physical alteration: plants, according to Aristotle, are altered by objects in their environment, but they do not sense them.
I won’t belabor the points which I have made here: I shall leave it to readers to decide whether I have summarized Aristotle’s thought fairly and accurately.
Belief in materialism does not entail a denial of direct realism
In his article, Professor Egnor seems to assume that if one is a materialist, then one must be committed to a denial of the claim that we perceive objects directly. As he puts it:
In the materialist view, when you perceive an object, what really happens is that the primary qualities of the object stimulate a sense organ of yours (a touch receptor, or a retinal cell, or a cochlear cell, etc.). The stimulus is transmitted to your brain, and it is in your brain that the stimulus acquires its secondary qualities — pain, or vision, or hearing. The pain or color or harmony isn’t really in the object perceived. It’s in your brain.
You don’t really perceive the object in your environment directly; you perceive the secondary qualities that are evoked in our brain by the transmission of the nerve stimulus, which is excited by the primary qualities
I have to say that the conclusion doesn’t follow. First, it is incorrect to say that “the primary qualities of the object stimulate a sense organ of yours”; qualities aren’t substances, so they don’t do anything. It would be better to say that the object itself stimulates your sensory organ, by virtue of its primary qualities. Second, the fact that the secondary qualities of the stimulus – e.g. the pain it causes you to feel – are entirely in your brain – doesn’t imply that you don’t perceive the object directly. Still less does it imply that “you perceive the secondary qualities that are evoked in our brain.” No; what I perceive is the object itself, and the secondary qualities are that whereby I perceive it. Secondary qualities, like primary qualities, are not “things” in their own right; hence it makes no sense to say that I can ever perceive them. What I perceive are objects.
At this point, someone is bound to object: “What about hallucinations, then?” But as philosopher John Searle has pointed out, the fallacy underlying this objection is the implicit assumption that (as he puts it), “if there’s something significant in common between the perception [of an object – VJT] and the indistinguishable hallucination, then that thing must be the object that you perceive.” There’s no reason why that has to be the case. As Searle explains in his essay, Perceptual Intentionality (Organon F 19 (2012), pp. 9-22):
Now let us apply this to the famous Argument from Illusion that we considered earlier. In the sense in which I am aware of an object when I look at the desk, the intentionality sense, in that sense when I have a hallucination [of a desk – VJT], I am not aware of anything. There is nothing there; hence I could not be aware of anything. Nonetheless, I am having a conscious visual experience and it is tempting, given the way our language works, to erect a noun phrase to stand for that awareness and make it into the object of the verbs of perception. So “aware of”, “conscious of”, are used in two different senses. We feel immediately hesitant to say that one “sees” anything in the hallucination case, so we are tempted to put sneer quotes around “sees”. But what is going on, I hope, is obvious and clear. In every case there is an ambiguity in the crucial phrases “aware of” or “conscious of”; because in the intentionality sense in which I am aware of something when I see it, in the case of the hallucination I am not aware of anything. I have a conscious experience, but that conscious experience is not itself the object of the experience; it is identical with the experience.
Once pointed out that this is such an obvious fallacy it is hard to see how anybody could have made it; but nonetheless there it is and it produced the idea that is common to the Great Philosophers that one does not perceive the world or does not perceive it directly. One perceives only the contents of one’s own mind, one’s own sense data. (2012, p. 11. Emphases mine – VJT.)
In short: the belief that secondary qualities (conscious experiences such as colors, sounds and pains) are located entirely within our brains is perfectly compatible with a thoroughgoing and direct version of realism.
Primary and secondary qualities: is there a distinction between the two?
Professor Egnor is right about one very important point: Aristotle did not recognize a distinction between primary and secondary qualities. For him, perception unaccompanied by awareness (including desire) would have been an oxymoron: to sense something as pleasant (or painful) goes hand-in-hand with desiring to enjoy it (or avoid it).
Is Aristotle the voice of common sense? Has modern philosophy led us badly astray, as Egnor believes? Whatever its faults and failings may be, I am very glad that modern philosophy draws a distinction between first-person (or subjective) and third-person (or objective) properties. Logically, there is no reason why an organism with the ability to detect and avoid noxious stimuli or seek out pleasant stimuli should possess any subjective feelings at all – even low-level ones, such as twinges of pain. It is perfectly conceivable that the organism should behave as it does, simply because it has been designed that way, and because such behavior helps it to survive. Nociception (avoidance of noxious stimuli) and pain are two very different things, as Rose points out in his article.
To laypeople, the idea of an organism being able to sense objects, and even learn about them, without being phenomenally conscious of them, might sound strange. But the fact that these activities are typically conscious in human beings does not entail that they have to be in all animals.
On the other hand, there are some behaviors observed in “higher” animals which are very hard to account for, except on the hypothesis that they are conscious. Petra Stoerig and Alan Cowey’s article, Blindsight in man and monkey (Brain (1997), 120, 535–559) describes a case in point. To put it very simply: if monkeys can hallucinate and experience after-images, then that would seem to indicate that they are phenomenally aware, and that there is “something that it is like” (as philosopher Thomas Nagel would put it) to be a monkey.
Finally, it seems to me that the Aristotelian view that colors, smells, tastes etc. reside in objects themselves strikes me as not only peculiar, but superfluous. Consider a lemon. Are we supposed to believe that in addition to having various physical properties, including a tendency to reflect light at a wavelength of 570 to 590 nanometers, produce citric acid when squeezed, and emit certain oils from its peel, the lemon also has various built-in psychic properties, such as a built-in tendency to appear yellow, taste sour, and smell clean and fresh to human beings? The mind boggles. One wonders: did lemons have these properties before humans and other conscious animals appeared? Such a view of nature strikes me as animistic.
What’s more, it seems that these psychic properties are redundant. Positing them would make good sense if the sensory organs detecting the color, taste and smell of lemons were capable of conscious awareness, but as we have seen, they are not. They can even be replaced (to some degree) by man-made prosthetic parts (e.g. the bionic eye) which are certainly devoid of consciousness. It is only when the sensory signals reach the associative regions of the brain that we become conscious of what we sense. Consequently, there is no need to posit properties in the lemon itself which engender conscious states. All we need suppose is that when the signals reach the neocortex, which possesses the unique structural features of “(1) exceptionally high interconnectivity within the neocortex and between the cortex and thalamus and (2) enough mass and local functional diversification to permit regionally specialized, differentiated activity patterns” (Rose, 2002; cited from Edelman and Tononi, 1999), they then become conscious. In other words, the subjectively felt color, taste and smell of a lemon are not found in the lemon itself; they arise from the highly inter-connected brains of humans and some “higher” animals. (In my thesis on animal minds, I tentatively conclude that mammals, birds, and just possibly reptiles and cephalopods are phenomenally conscious.)
In saying that phenomenal consciousness can arise from an inter-connected brain, I am not in any way arguing that reflective consciousness, which is unique to human beings, can arise in this way. On Aristotle’s view, the discontinuity between humans and other animals is far more profound than that between animals and plants, which he viewed as a rather blurry one. I completely agree. An animal that can understand the abstract notion of a rule, as well as the notions of truth and falsity, belongs in a category of its own. The formal logic which we engage in cannot be equated with any material process.
As I pointed out above, there are several possibilities to consider besides the bizarre view put forward by Professor Egnor, that your perceptions are located at the object perceived, regardless of its distance from you. One possibility is that they are located in the sensory organ that is affected by the stimulus. Another is that they are located partly in the sensory organ, and partly in the brain. A third possibility is that they are located entirely in the brain, since that is where the signal produced by an external stimulus, which is transmitted inside your body, finally becomes conscious.
As I see it, the drawback of the first possibility is that if it is correct, then our perceptions are not conscious; for my eye is certainly not conscious of anything. People with bionic eyes can still see, after a fashion – and yet nobody would say that a bionic eye is conscious. In addition, my spectacles (which I purchased recently for just 80 U.S. cents, at a 100-yen store in Japan, to counteract worsening long-sightedness) certainly help me to see clearly; and if the act of seeing is supposed to take place in my eyes, and not in my brain, then by the same token, we should grant that for visually impaired people, the act of seeing takes place in their spectacles as well.
The third possibility, however, is decidedly counter-intuitive, for it entails that my eyes don’t see anything, my ears don’t hear anything and my skin doesn’t feel anything. Now, if someone wanted to say that my eyes don’t consciously see anything, then I’d have no problem with that.
The second possibility therefore seems to be the most sensible one: my perceptions are located partly in my sensory organs, and partly in my brain. Insofar as they are perceptions of external objects, my perceptions can be located in the organs affected by those objects. But insofar as they are conscious, my perceptions are located in my brain – and in particular, my neocortex, and especially the association regions, which play a central role in consciousness. What this view entails is that perceptions are composed of conscious and non-conscious components, and that my perceptions begin a very short time before I become aware of them. That might strike some people as a little odd, but I can live with it.
Perceptions have generated a great deal of philosophical controversy over the past 2,400 years, and I’m sure they will continue to do so. Some of the opinions I’ve expressed in this article are almost certainly wrong; but I’m about as certain as I can be of anything, that when I look at the moon, my perception of the moon is somewhere within my body, and not on the moon.
What do readers think?