Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site uwmacc.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!godot!harvard!seismo!uwvax!uwmacc!dubois From: dubois@uwmacc.UUCP (Paul DuBois) Newsgroups: net.origins Subject: Integrated Circuits. Part II. Message-ID: <502@uwmacc.UUCP> Date: Fri, 30-Nov-84 15:29:23 EST Article-I.D.: uwmacc.502 Posted: Fri Nov 30 15:29:23 1984 Date-Received: Sun, 2-Dec-84 04:12:34 EST Distribution: net Organization: UW-Madison Primate Center Lines: 304 This article accompanies another on a related topic. In that article, a partial response to Bill Jefferys' comments on the argument from design was given. Further remarks are given below. > [Bill Jefferys] > Indeed, one can argue just as persuasively that life as we see it > on Earth is so kludgy that it could *must* have arisen by chance. > Rather than showing evidence of careful design, it shows instead > incredible (and stupid) complexity, just what one would expect from > opportunistic evolution. This kludgyness is seen both at the molecular > level (where, for example, a very large proportion of the DNA in the > human body codes for *absolutely nothing*), and at the organ level > (remember the Panda's thumb, Ray? How about the human eye, whose > overall design is clearly inferior to that of the octopus?) The comments Bill refers to in the last sentence are from article 663@utastro, excerpted below: > Baloney. Creationists love to point to the complexity of life as > evidence of the superb engineering skills of the Creator, yet when > anyone points out a place where the design is obviously faulty, they > pull themselves up and haughtily say, "Well, who are you to question the > wisdom of the Almighty?" Sorry, Ray, you can't have it both ways. > Omniscience isn't needed, only common sense. Let me counter with > another example: One doesn't have to be omniscient to know that the basic > design of the retina of an octopus eye is considerably better that of > the human eye. We have a "blind spot" where the optic nerve enters the > eye; octopi do not. Pray tell, if we are at the pinnacle of Creation, > how come the Creator got it right with the octopus and then stuck us > with a second-rate design? Here is a set of propositions which may be derived from the above two paragraphs. (a) creationists wish to have it both ways - elegant complexity points to a designer, while suboptimal complexity must not be taken as evidence against a designer, presumably because his thoughts are higher than our thoughts and his ways than our ways, and so we shall never understand his wisdom. (this derives from statements in the second excerpt) (b) if humans are the pinnacle of creation, there should be no sensory function which a human performs more poorly than any other created organism. (last sentence of second excerpt) (c) a blind spot constitutes a design fault. (last half of excerpt 2) (d) a design fault constitutes inferiority of an organ relative to that same organ in another organism which fails to manifest that fault. (last sentence of first excerpt; two sentences in middle of second excerpt) I will discuss these in order. (a) If it is true that creationists take this position as I have stated it, and I think it may be reasonably maintained that some do, then indeed a self-defeating position has been taken, at least in the absence of proof that we shall *never* understand the function of such complexities. But one need not pull oneself up haughtily when faced with faulty design. One might, for instance, simply suspend judgment in such cases, and await further information which would allow a better evaluation of the situation to be made. If a more positive statement were desirable, one might infer a principle of genetic deterioration in consonance with the tenet of physical degeneration that seems to be a part of the standard creationist model, citing as specific evidence the deleterious or lethal nature of many mutations. (To be sure, without a more specific formulation, one immediately runs into problems. For example, *when* should we expect to find genetic disintegration, and *why* should we expect to find it *then* and not otherwise? Under what specific conditions ought it to occur? This is one analogue of a difficulty in evolutionary theory, viz., stasis: *when* will an organism undergo change and *why*? Under what specific conditions will an organism stay the same for millions of years, while others do not?) (b) Bill asks why the creator "got it right" with the octopus but not with us. First of all, this presumes that we know what the "right" design is. But perhaps we do; so I will pass over that for now. The real difficulty with the comment is the implication that a human, at the pinnacle of creation, ought to be endowed with better sensory capacities than lower organisms. This is a dubious proposition at best, not least because it equates sensory capacity with worth in the eyes of a creator (and how is that ascertained?). A more serious biological objection is that organisms occupy different ecological niches. It is to be expected that they shall be different in certain ways, whether they arose by evolution or by non-evolutionary design. If they arose by evolutionary processes, then the differences between organisms are at least in part what *allows* them to occupy their specific niche. If they were created, presumably they were created with different capacities for the *purpose* of fitting them to their niche (although, who knows?). But unless one can demonstrate that the niche occupied by man *requires* better sensory capacities than all other organisms, the proposition is without premise. It is not simply a question of improving one aspect of a sensory channel while leaving all other aspects intact, either. Consider the cat eye and the human eye. The eye of a cat is more highly sensitive to light in the night than the human eye. By Bill's line of reasoning, this would imply that the creator "got it right" with the cat, but not with us. While better night vision is arguably a desirable characteristic, it is not necessarily so. The cat achieves its higher sensitivity primarily by two means. First, a reflective material located behind the photoreceptors bounces the light back for a second chance at being grabbed. (That is why cat eyes "glow".) Second, there is a higher (than human) degree of convergence of photoreceptors onto the ganglia. A ganglion will not transmit a neural implulse until it reaches threshold; a greater number of photoreceptors converging on the ganglion increases its input and therefore the likelihood of reaching threshold. But the increase in sensitivity is not without its disadvantages. Both of these structural characteristics lead to loss of acuity. Light does not bounce around in the human eye as it does in the cat, because a dark pigment behind the photoreceptors absorbs it. An analogy that the astronomers in this group will easily appreciate is that of an observatory located near to a large city. When a lot of city lights are on, the chance of light *detection* increases but the *resolution* of the optical instrument goes down, because city light bouncing around is noise from the astronomer's viewpoint. The greater degree of convergence in the cat produces somewhat the same effect, though for a different reason. With a larger number of photoreceptors connected to a ganglion, the size of its retinal receptive field is increased. In engineering terms, this receptive field may be considered an aperture, where an increase in aperture size lowers the frequency range that can be passed by it. This is reflected in the fact that the frequency transfer function of the cat retina is shifted downward by an octave or more relative to that of the human. So, do we wish to increase our nighttime sensitivity, given the functional price to be paid? I think not. It can be seen from this that the statement about "getting it right" and "second-rate design" is a bit facile. I find it curious that evolutionists continually raise the point about our inability to predict, *a priori*, any limits on the way in which a creator would create - and then go ahead and make their own suppositions. (c) The contention is that the blind spot constitutes faulty design. Does it? Perhaps. Let us examine the question. A blind spot is an area of the retina from which no visual information may be received. In the vertebrate eye this is a consequence of the fact that photoreceptors are "backward". The receptors are oriented with the photoactive part pointed toward the back of the eye, while the ganglia to which they are (indirectly) connected pass their axons out of the front of the retina. The axons all converge at a point near the fovea (area of greatest acuity) and pass out together through the rear of the ocular globe, forming the optic nerve. At this point of convergence there are no photoreceptors, hence no visual information about the portion of the visual field projecting on that area. Hence the term blind spot. For an *actual* disability to result from this physiological structure, the possessor of the eye must be: (i) Unable to move the eye (for otherwise a visually receptive portion of the retina could be rotated to receive information from the part of the visual field corresponding to that projecting on the blind spot). (ii) Unable to move the head (such movement would allow crude approximation of eye movement). (iii) Unable to move the body (ditto). (iv) Monocular, because the blind spots of binocular organisms do not correspond to the same part of the visual field. Clearly, any sighted organism satisfying all of these criteria may have more serious things to worry about than a lack of visual capacity in a certain portion of its retinae. The argument may be extended in a certain way by observing that we have a rather more serious blind spot. It's called the back of the head. To eliminate this functional disability, we should require 360 degree vision. Perhaps we should have eyes on the bottom of our feet. Maybe the whole body needs to be an eye. This would overcome all possible blind spots. But "if the whole body were an eye, where were the hearing?" You see what I'm driving at. The blind spot may *seem* to be a fault of design, but it simply is not important in a functional sense. Ask your friends to find theirs. How many of them can do it? Even those who can must engage in a certain amount of trial and error to locate it. This suggests a minimal or nonexistent incapacity. Certainly point (iv) above provides a partial explanation of why this is so: One of many consequences of binocularity is that the blind spot becomes pretty much irrelevant, since the fields of vision subtended by the two eyes in the areas of the blind spots do not overlap. The brain also, to a certain extent, compensates in curious ways under conditions of monocular viewing. A checkerboard grid may be modified by placing a small circular patch where four squares join. When foveal retina is rotated under the image of the patch (i.e., when you "look at it"), you see the patch, as might be expected. But then the blind spot is rotated under the image, an unmodified checkerboard is perceived: the patch disappears (assuming the visual angle of the patch is less than that subtended by the blind spot, of course). The brain seems to generate a hypothesis about what "ought" to be seen. The regular pattern of the checkboard allows an obvious inference as to the nature of that hypothesis, which in the above case is incorrect. Who know why this should occur? Why should we just not perceive a hole in the visual field? I don't know. It certainly seems an odd thing for a creator to build in; it seems extraordinary that it should arise through evolutionary processes. For my money, I'll bet on a designer. Perhaps that is unsafe: I'm sitting on an invalid philosophical position while "real" scientists gather hard data. Don't they. (d) Bill has discussed one aspect of visual function (ther retinal blind spot), concluding that the evidence implies inferiority of the human eye. My comments in the previous section lead to a different conclusion, but I still have to ask in a more general sense how the human eye is "clearly inferior" to the octopus eye. Bill mentions the overall design ("design" being a poor word given the thrust of his argument), but his comments only discussed the design of the retina. This is certainly artificial; a retina is useless by itself. Let us consider general ocular superiority. This would include consideration of such things as the following: o accommodative ability o chromatic and spherical aberration of the lens o pupillary reflex o vergence and version control for binocular functioning o stereopsis o resolution of extraocular muscle nervous innervation o night/day visual capacity, pattern of neural convergence of the photoreceptors onto the ganglia (already discussed) o color vision o rod/cone demography o response to foreign objects (i.e., defense against) o facilities for distance perception Consider stereopsis. This requires coordination of convergence, version, accommodation, as well as a host of neural machinery capable of performing immense data reduction and blindingly fast autocorrelation functions. For all of this complexity we should perhaps expect some functional benefit. The most obvious observation is that distance information may be computed from the disparity of the images falling on the two retinae. Octupi, though binocular, apparently do not have stereopsis. They bob their heads, evidently for the purpose of obtaining parallax information from which distance may be calculated. Leaving aside the question of how any organism could develop *that* ability through evolutionary processes, consider: does the lack of stereopsis imply that the octopus eye is "clearly inferior"? Some further examples: One might say the the human eye is clearly inferior to that of the hawk or the eagle, since the angular resolution of the human eye is poorer. Or that the human eye is clearly inferior to that of the honeybee, since the human eye cannot perceive infrared. Or that the human eye is clearly inferior to that of the housefly, since the human eye does not have as large an angular subtense. Or that the human eye is clearly inferior to that of any number of flying insects because its ability to resolve visual stimuli under conditions of motion is not as great. Or that the human eye is clearly inferior to that of the Anableps fish, since our eye is not developed in such a way as to allow us to see above and below water simultaneously when the eye is placed at the air-water boundary. Or that the human eye is clearly inferior to that of several other fish since the visible part of the globe is not camouflaged to blend in with the rest of the head. Or that the human eye is clearly inferior to that of the chameleon, since we cannot move the eyes in an independent fashion. What's the point? Simply that it is silly to examine one dimension of an organ subserving multidimensional functionality, compare the organ in two organisms, and then conclude that the organ having poorer functionality (in regard to that single aspect) is inferior. The relative superiority argument, even if it were correct, obscures one basic point: the human eye and the octopus eye *both* are magnificent examples of extraordinary complexity. Call me naive if you wish. I find the eye a thing of beauty, not an example of stupid complexity. --- Well, anyway. Bill referred to overall design, but mentioned only the retina and the blind spot specifically. Perhaps he would like to restate his case, so I will leave off here. -- Paul DuBois {allegra,ihnp4,seismo}!uwvax!uwmacc!dubois