Friday, February 5, 2010

How to REALLY read Darwin

Over the years I've studied Darwin's Origin and people's interpretations of it, and I've come to a fascinating conclusion. Darwin's work is often misinterpreted. I know, it's not a shocking secret, but there is one persistent and pernicious misreading of Darwin that really gets my goat. I've been procrastinating on writing this, but a comment I left over at Steve Matheson's blog got my thoughts going. So here we go.

Darwin frequently discusses the "theory of creation" in Origin, often contrasting it to his own ideas of descent with modification. I think it's very easy for those of us who hold to a "theory of creation" (there are many) to react negatively to Darwin's constant chiding that creation offers no explanation for a host of facts. In doing so, I think we risk losing track of Darwin's point. In other words, I think it's important to swallow our pride for a moment and actually listen to what Darwin is saying. If we do, I think we'll find that he has some important points to make.

What follows is a sampling of references to creation in the first edition of Origin, which I compiled just now from the electronic version at Darwin Online. I have tried to be thorough, but I make no claim to completeness. After all, this is just a blog post not a scholarly paper. The quotes are quite long, since Darwin talks a lot about creation. Some of you might want to skip to the discussion at the end.
On the other hand, if we look at each species as a special act of creation, there is no apparent reason why more varieties should occur in a group having many species, than in one having few. (p. 55)
He who believes in the creation of each species, will have to say that this shell, for instance, was created with bright colours for a warm sea; but that this other shell became bright-coloured by variation when it ranged into warmer or shallower waters. (p. 133)
It would be most difficult to give any rational explanation of the affinities of the blind cave-animals to the other inhabitants of the two continents on the ordinary view of their independent creation. (p. 139)
According to the ordinary view of each species having been independently created, we should have to attribute this similarity in the enlarged stems of these three plants, not to the vera causa of community of descent, and a consequent tendency to vary in a like manner, but to three separate yet closely related acts of creation. (p. 159)
He who believes in separate and innumerable acts of creation will say, that in these cases it has pleased the Creator to cause a being of one type to take the place of one of another type; but this seems to me only restating the fact in dignified language. (pp. 185-186)
Why, on the theory of Creation, should this be so? Why should all the parts and organs of many independent beings, each supposed to have been separately created for its proper place in nature, be so invariably linked together by graduated steps? (p. 194)
We have in this chapter discussed some of the difficulties and objections which may be urged against my theory. Many of them are very grave; but I think that in the discussion light has been thrown on several facts, which on the theory of independent acts of creation are utterly obscure. (p. 203)
Cases of this nature are common, and are, as we shall hereafter more fully see, inexplicable on the theory of independent creation. This view of the relation of species in one region to those in another, does not differ much (by substituting the word variety for species) from that lately advanced in an ingenious paper by Mr. Wallace, in which he concludes, that "every species has come into existence coincident both in space and time with a pre-existing closely allied species." And I now know from correspondence, that this coincidence he attributes to generation with modification. (p. 355)
These cases of relationship, without identity, of the inhabitants of seas now disjoined, and likewise of the past and present inhabitants of the temperate lands of North America and Europe, are inexplicable on the theory of creation. (p. 372)
These cases of relationship, without identity, of the inhabitants of seas now disjoined, and likewise of the past and present inhabitants of the temperate lands of North America and Europe, are inexplicable on the theory of creation. (p. 390)
This general absence of frogs, toads, and newts on so many oceanic islands cannot be accounted for by their physical conditions; indeed it seems that islands are peculiarly well fitted for these animals; for frogs have been introduced into Madeira, the Azores, and Mauritius, and have multiplied so as to become a nuisance. But as these animals and their spawn are known to be immediately killed by sea-water, on my view we can see that there would be great difficulty in their transportal across the sea, and therefore why they do not exist on any oceanic island. But why, on the theory of creation, they should not have been created there, it would be very difficult to explain. (p. 393)
It cannot be said, on the ordinary view of creation, that there has not been time for the creation of mammals; many volcanic islands are sufficiently ancient, as shown by the stupendous degradation which they have suffered and by their tertiary strata: there has also been time for the production of endemic species belonging to other classes; and on continents it is thought that mammals appear and disappear at a quicker rate than other and lower animals. (p. 394)
As the amount of modification in all cases depends to a certain degree on the lapse of time, and as during changes of level it is obvious that islands separated by shallow channels are more likely to have been continuously united within a recent period to the mainland than islands separated by deeper channels, we can understand the frequent relation between the depth of the sea and the degree of affinity of the mammalian inhabitants of islands with those of a neighbouring continent, - an inexplicable relation on the view of independent acts of creation. (p. 395-396)
I believe this grand fact can receive no sort of explanation on the ordinary view of independent creation; whereas on the view here maintained, it is obvious that the Galapagos Islands would be likely to receive colonists, whether by occasional means of transport or by formerly continuous land, from America; and the Cape de Verde Islands from Africa; and that such colonists would be liable to modification; - the principle of inheritance still betraying their original birthplace. (p. 398-399)
The relations just discussed, - namely, low and slowly-changing organisms ranging more widely than the high, - some of the species of widely-ranging genera themselves ranging widely, - such facts, as alpine, lacustrine, and marsh productions being related (with the exceptions before specified) to those on the surrounding low lands and dry lands, though these stations are so different - the very close relation of the distinct species which inhabit the islets of the same archipelago, - and especially the striking relation of the inhabitants of each whole archipelago or island to those of the nearest mainland, - are, I think, utterly inexplicable on the ordinary view of the independent creation of each species, but are explicable on the view of colonisation from the nearest and readiest source, together with the subsequent modification and better adaptation of the colonists to their new homes. (p. 406)
All the foregoing rules and aids and difficulties in classification are explained, if I do not greatly deceive myself, on the view that the natural system is founded on descent with modification; that the characters which naturalists consider as showing true affinity between any two or more species, are those which have been inherited from a common parent, and, in so far, all true classification is genealogical; that community of descent is the hidden bond which naturalists have been unconsciously seeking, and not some unknown plan of creation, or the enunciation of general propositions, and the mere putting together and separating objects more or less alike. (p. 420)
Nothing can be more hopeless than to attempt to explain this similarity of pattern in members of the same class, by utility or by the doctrine of final causes. The hopelessness of the attempt has been expressly admitted by Owen in his most interesting work on the 'Nature of Limbs.' On the ordinary view of the independent creation of each being, we can only say that so it is; - that it has so pleased the Creator to construct each animal and plant. (p. 435)
How inexplicable are these facts on the ordinary view of creation! Why should the brain be enclosed in a box composed of such numerous and such extraordinarily shaped pieces of bone? As Owen has remarked, the benefit derived from the yielding of the separate pieces in the act of parturition of mammals, will by no means explain the same construction in the skulls of birds. Why should similar bones have been created in the formation of the wing and leg of a bat, used as they are for such totally different purposes? Why should one crustacean, which has an extremely complex mouth formed of many parts, consequently always have fewer legs; or conversely, those with many legs have simpler mouths? Why should the sepals, petals, stamens, and pistils in any individual flower, though fitted for such widely different purposes, be all constructed on the same pattern? (p. 437)
On the view of descent with modification, we may conclude that the existence of organs in a rudimentary, imperfect, and useless condition, or quite aborted, far from presenting a strange difficulty, as they assuredly do on the ordinary doctrine of creation, might even have been anticipated, and can be accounted for by the laws of inheritance. (pp. 455-456)
This grand fact of the grouping of all organic beings seems to me utterly inexplicable on the theory of creation. (p. 471)
How inexplicable on the theory of creation is the occasional appearance of stripes on the shoulder and legs of the several species of the horse-genus and in their hybrids! How simply is this fact explained if we believe that these species have descended from a striped progenitor, in the same manner as the several domestic breeds of pigeon have descended from the blue and barred rock-pigeon! (p. 473)
It is inexplicable on the theory of creation why a part developed in a very unusual manner in any one species of a genus, and therefore, as we may naturally infer, of great importance to the species, should be eminently liable to variation; but, on my view, this part has undergone, since the several species branched off from a common progenitor, an unusual amount of variability and modification, and therefore we might expect this part generally to be still variable. (p. 474)
Such facts as the presence of peculiar species of bats, and the absence of all other mammals, on oceanic islands, are utterly inexplicable on the theory of independent acts of creation. (pp. 477-478)
The existence of closely allied or representative species in any two areas, implies, on the theory of descent with modification, that the same parents formerly inhabited both areas.... It must be admitted that these facts receive no explanation on the theory of creation. (p. 478)
It is so easy to hide our ignorance under such expressions as the "plan of creation," "unity of design," &c., and to think that we give an explanation when we only restate a fact. (pp. 481-482)
Several eminent naturalists have of late published their belief that a multitude of reputed species in each genus are not real species; but that other species are real, that is, have been independently created. This seems to me a strange conclusion to arrive at. They admit that a multitude of forms, which till lately they themselves thought were special creations, and which are still thus looked at by the majority of naturalists, and which consequently have every external characteristic feature of true species,—they admit that these have been produced by variation, but they refuse to extend the same view to other and very slightly different forms. (p. 482)

The first thing I noticed as I compiled this list is that his references to "creation" are nonrandom. The first edition of Origin has a text of 490 pages, and of the 26 citations I list here, there are only seven (27%) in the first half of the book. Thematically, he concentrates his comments on creation around two primary phenomena, what we now call biogeography and homology. I realize that he also talks about other issues, but he more frequently references creation on those two topics I mentioned.

His arguments are quite simple: If species arise from other species, then a host of facts about their geographical distribution become easily explained. On the view of creation those facts are just facts. Likewise, if modern species descend from a common ancestor, then homology and classification become explicable as the result of familial relationship. Under creation, again these facts are just facts.

Those acquainted with nineteenth century biology debates have already recognized the two different theories that Darwin is critiquing in his discussion of the theory of creation. The first is related to the origin of species by creation, the notion that species just pop into existence where they did not exist before. Variations of this include Lyell's "centers of creation," which posited single geographic origins of species and subsequent dispersal, and Agassiz's extreme view that species are created as full populations in their present geographic ranges. The second theory is Owen's doctrine of the "vertebrate archetype," the notion that God used a basic vertebrate plan to create all the different vertebrates. Obviously the two theories are interrelated (by the concept of creation), but they quite different kinds of data (the first data from natural history and the second from comparative anatomy).

Now here's the real kick in the pants: I agree with Darwin's assessment of nineteenth century theories of creation. Just arbitrarily attributing the origin of species to an unknown act of creation does not explain their geographic affinities. That's why I do not ascribe to species fixity. I also agree that chalking up homology to a common designer (or design plan) is arbitrary. There's no explanation for why the Creator chose one particular plan over another or why there is so much variety. This is an issue I have discussed time and time and time again.

We also need to realize, though, that the particular nineteenth century theories of creation that Darwin (effectively) critiqued are not the sum total of all possible creation theories. This is where I think much of the anticreationist rhetoric really fails miserably. For example, lots of folks like to tell us that endemic species on islands are obviously related to those on the nearest mainland, therefore special creation is wrong!!! That's only true if we espoused a Lyellian or Agassizian view of "special creation." Many other creation theories are impervious to such a critique.

As Darwin himself recognized, his theory does not address the philosophical/theological question of whether God was involved somehow in creation. In a letter to Asa Gray, Darwin took a kind of deistic view ("I am inclined to look at everything as resulting from designed laws, with the details, whether good or bad, left to the working out of what we may call chance."), but ultimately confessed that he was bewildered by these thoughts that are "too profound for the human intellect." "A dog might as well speculate on the mind of Newton."

Given what Darwin actually wrote in Origin, I see no reason whatsoever to doubt him on this point. His points in Origin address very specific and unsatisfactory ideas common in the nineteenth century, but they do not address the overarching question of whether or not God was involved with creation. I think Darwin has done creationism a great favor by helping to clear away wrong ideas of the past and by laying out plainly the kind of data that any future creationist theory must address.

Astute readers might be thinking something like this: Wait a minute! You and Darwin are making theological arguments! So? Seriously, so what? Scientists from Galileo to Dawkins have made theological/philosophical arguments central to their interpretation of data. Why should we be any different? Big deal. I suspect that when dealing with such large questions like those posed by origins, philosophical and theological ideas are inescapable. Yes, I realize that anticreationists today like to pretend that evolution is strictly about interpretation of the evidence, and on one level they are right. They can approach the data as Darwin did without any particular discussion on the philosophical concept of creation. But we all know that there are deep theological and philosophical issues here, and nobody thinks in a vacuum.

So in the end, I am thankful that Darwin has assisted us in understanding the world. I'm sad that he used his considerable intellect and talent to propose a theory that is so inconsistent with the history revealed in Genesis, but in that he was merely a product of his time. But that's a topic for another post. This one's long enough.