26 in 2006, how many now?

A list of 26 Species “Concepts”

Francis J. Beckwith, St. Thomas Aquinas and the Inadequacy of Intelligent Design

"Ethan" comments and cites St. Thomas:

Accordingly, there is diversity and inequality in things created, not by chance, not as a result of a diversity of matter, not on account of certain causes or merits intervening, but from God’s own intention…

The distinction of things is not from chance… those things which are distinct by their forms are not distinct by chance, but perhaps those things are, whose distinction is from matter. But the distinction of species is from the form, and the distinction of singulars in the same species, is from matter. Wherefore the specific distinction of things cannot be from chance…

It follows therefore that theform of the universe is intended and willed by God. Therefore it is not from chance: for we ascribe to chance those things which are beside the intention of the agent. Now the form of the universe consists in the distinction and order of its parts. Therefore the distinction of things is not from chance.

Therefore the specific distinction in things, which is according to their form, is not on account of their matter: but on the contrary matters were created diverse, that they might be suitable for diverse forms. Hereby is excluded… the opinions of any who held the distinction of things to be the result of various material principles.

I'll have to look this up when I get a chance.

Stephen Barr on science and metaphysics

Stephen Barr, The Symbiosis of Science and Metaphysics (via Joe Carter).

The arrogance of scientists lecturing to philosophers on how they should do philosophy? That is what I thoght at first, especially when Naturally, John Farrell expressed his appreciation at First Things, especially of the closing:

In short, Aristotelian/Thomistic philosophy has paid a heavy price for the two and a half centuries in which it largely ignored what was going on in the natural sciences. A sustained re-engagement with science would enrich its conceptual and linguistic resources. This re-engagement cannot simply be an attempt to translate statements of modern science into existing Aristotelian terms. That cannot be done in many cases. Rather, many more Aristotelian/ Thomistic metaphysicians than currently do must learn to listen to and understand science in its own native tongue.

But then I went ahead and read the rest of the essay.

Beyond directly theological issues, does modern physics have anything to say to metaphysics, and therefore indirectly to theology? Some might argue not, on the grounds that metaphysics speaks about such general features of reality - of being as being - that it cannot be affected by discoveries of particular contingent facts about the world. And yet, Aristotelian metaphysics, which has such an important place in Catholic thought, was not conceived in isolation from scientific investigation. Aristotle was himself a great scientist and both his metaphysics and science make use of the same technical apparatus of form, matter, substance, accident, potency, act, and so on. Indeed, it was largely as a theory of nature that Aristotelianism first commended itself to medieval Christian thinkers.


It is a great problem that traditional Aristotelian/Thomistic metaphysics and modern science no longer speak the same language, as they did in the Middle Ages. Indeed, there are many terms and concepts in the language of each that are now almost untranslatable into the language of the other. Some argue that this is the fault of modern science, which restricted its attention to a limited range of questions having to do with the merely quantitative aspects of things and with efficient and material causes at the expense of formal and final causes. While there is some truth in this, it is only a part of the story. The language of Aristotelian/Thomistic metaphysics has changed very little since the advent of modern science and its vocabulary seems from a scientific perspective quite stilted and awkward for many purposes.


Physics has had enormous success in explaining why things happen as they do in the natural world, but its modes of explanation do not fit neatly into the four-fold classification of material, formal, efficient, and final causes. For example, when physicists explain the electrical conductivity of metals in terms of the "band structure" of the energy levels of the electrons in a crystal lattice of atoms, to which of the four causes does that correspond? As this example illustrates, explanation in modern physics is almost entirely in terms of mathematical structure and involves an enormously rich set of ideas about form. The fact that modern science is nonetheless typically accused by Aristotelian/Thomistic metaphysicians of neglecting "formal cause" shows that they are working with a different notion of form than are contemporary physicists and mathematicians. In Aristotelian/Thomistic philosophy, the ideas of formal causation and substantial form have a teleological thrust that is largely missing from the physicist's conception of form, which corresponds more to Lonergan's broader idea of form as "intelligible structure".


Another example of a linguistic/conceptual difference between Aristotelian thought and modern science is that the former usually envisions the action of one thing upon another (for example fire heating iron), whereas in modern physics the physical world is explained in terms of mutual "interactions". A third example is that the notions of "species" in Aristotelian philosophy and modern biology are not compatible. Aristotelian species are what mathematicians call "equivalence classes", so that if A is of the same species as B, and B is of the same species as C, then A must be of the same species as C. However, it does not appear possible in biology to define species in a way that always satisfies this condition. (The existence of "ring species", such as the Larus gulls, illustrates the problem, as indeed does "speciation" in evolution, whereby all animals are of the same species as their parents and offspring, but not as their remote ancestors or descendents.)

He makes some good point about Aristotle being a "scientist" and a "philosopher." But the rest...

Even if they are well-meaning, Catholic scientists who would seek to advance the credibility of the Church and the Catholic intellectual tradition should instead examine their starting points and assumptions, and check their reasoning. Those philosophers and theologians who would seek to have discussions with such scientists (as the River Forest School used to promote) should always check the logic (especially the definitions of terms).

Even now we still have some Dominicans of the River Forest School continuing the work of the school: Fr. William Wallace, especially. And then there is Anthony Rizzi, who was apparently influenced more by Maritain. Aristotelian-Thomists have no problems reviewing contemporary scientific literature -- what will irritate the Catholic scientists is when they do so critically. Philosophers and theologians of other schools may be more deficient in their training, so I would not suggest that they grapple with the literature right away--rather they should study logic, physics, and philosophy/history of science. Talking about the "mode of explanation" of Aristotelian physics shows that Barr has not gone far enough in a critical examination of what he believes. One does not evaluate what some philosophers have written with belief -- one must start off first by asking whether one has belief or true knowledge, and only then can one critique what others have said.

Aristotelian-Thomistic vocabulary begins with what we first know and it is used to understand what we come to know. We do not go in reverse, attempting to understand what is better-known through what is less-known, which is what contemporary scientists would have us do. If modern science is criticized as neglecting the formal cause, it is conjunction with critiques about its mathematical character and reductionism.

Barr concedes that physics almost entirely in terms of mathematical structure, and yet "involves an enormously rich set of ideas about form," using the example of electronic band structure, Claiming that is so does not make it so. What he neglects to examine is how one arrives at that mathematical structure in the first place -- quantity and measurement -- from what causal interactions are such measurements derived? Moreover, the avoidance of teleology does not make a causal (i.e. scientific) account of x wrong -- it merely makes it incomplete, and those who would maintain that this is a complete explanation (or the only one attainable) are therefore wrong.

As for species -- James Chastek has written something recently on this question, and I have yet to think about what he says. Is it necessary for an account using a more traditional notion of species ("kinds") to be reconciled with the modern biological notion? No. But that does not mean that it cannot be done, even if one can concede that species refer to populations of individuals that reproduce and are isolated from other populations (Ernst Mayr's definition). Talking about a group and its lineage of reproduction/descent does not exclude the possibility that there are natural limits to the variation of structure within that group/lineage.

Plus:
Philosophy Lives
Why Stephen Hawking’s attempt to banish natural theology only shows why we need it.
John Haldane

James Chastek: Aristotle and Darwin on Species: A Note

Plus he comment over at Edward Feser's blog.

Anon,

Mayer's phrasing is ambiguous, and the ambiguity is fatal, since it overlooks the whole point of Aristotle's account of a species and the whole problem of species in the Greeks. Consider when he attributes to Aristotle the idea that "each species possessed and unchanging nature or form"

1.) If he is assuming that "nature" and "form" are the same thing, he is fatally wrong. Nature is matter and form. One can only speak of "nature or form" interchangeably if he is speaking about an angel, or God, which means he is no longer speaking of natural things. Form is unchangeable, to be sure, but a nature is not identified with its form, and therefore not identified with its unchangeable aspect. On the most probable reading of this quotation, Mayer is destroying Aristotle's idea of nature.

2.) Nothing defined with matter can be "rigidly distinct" from anything else defined with matter, for several reasons:

a.) Matter is unintelligible to us in itself, and gives a margin of unintelligibly and fuzziness to any natural thing. Again, this is not particularly controversial stuff in Aristotelian interpretation, just as point on is not.

b.) Aristotle's account of the unchageability of form is inseparable from his understanding of the intelligibility of things. In the measure that we admit species are intelligible, we admit they have an unchageable form as Aristotle understood it. Again, since natural things are not just forms, they are not just intelligible, which Mayer seems to get, but he bungles the idea. Does Darwin doubt that species can be studied? If not, he admits some notion of form is Aristotle's sense to creep in.

c.) Mayer misses everything essential about the ancient debate about forms, change, motion, intelligibility, etc, all of which are all tied together. as far as I can tell, no one in the ancient or Medieval world held the opinion that Meyer attributes to Aristotle, except as a doctrine about the angels.

Throw the book away and read Books 1+ 2 of Aristotle's Physics.

James Chastek, Aristotle, essentialism, and evolution

When we simply plow through Aristotle’s text changing every “what is” to “essence” we will be prone to fall into exactly the sort of error that is thoroughly discredited by the insights of evolution. In Aristotle’s system, the “what”, when said of a natural thing, refers to a compositeof matter and form; when said of a being without matter thing, it refers to form alone. The first “what” is inseparable from a change and flux so far as it is defined with matter, and so if we say that “the what” means “essence” than the essence of natural things is changeable. Changeability is not the whole of its essence (for form is essential to its essence too) but it is inseparable from it. In this sense of essence, the essences of the things the natural scientist studies are changeable. The difficulty is that “essence”, because of its absolute character, cannot mix with the idea of being changeable. The mind recoils from the idea of “changeable essence” as a contradiction, or at least an extremely poor choice of words. This is why when we find various good reasons to say that essences (or what we thought were essences) are not fixed, it is better to junk the idea of essence altogether. This is fine, but even after we junk the word “essence” we are still left with Aristotle’s “the what”, which, when applied to natural things, includes matter and is therefore capable of change.

But Aristotle also says that nature is more form than matter, does he not, even though it is made up of both? And matter is proportioned to form -- so how much change can a thing tolerate before its potencies are affected, and it no longer has the same potencies as before?

James Prosek, The Failure of Names

via The Western Confucian--an article in the most recent issue of Orion Magazine: "The Failure of Names: An artist puts his faith in diversity over taxonomy," by James Prosek

Another salvo (perhaps unintended by the author) in the debate over classification and how the term species should be used in biology.

Brian Goodwin interview

source, alt

An Interview with Professor Brian Goodwin
by Dr. David King
David King is a molecular biologist and editor of GenEthics News.

Professor Brian Goodwin authored How the Leopard Changed Its Spots and is in the Department of Biology at The Open University, Great Britain.

The interview was published in GenEthics News, Issue 11, March/April 1996, pp. 6-8.

--------------------------------------------------------------------------------

David King:
What are your criticisms of the prevailing paradigms in biology, particularly Darwinism?

Brian Goodwin: My main criticism of Darwinism is that it fails in its initial objective, which is to explain the origin of species. Now, let me explain exactly what I mean by that. I mean it fails to explain the emergence of organisms, the specific forms during evolution like algae and ferns and flowering plants, corals, starfish, crabs, fish, birds. That sort of spectrum of organism, each of which is distinct from the other. They don't blend with each other, they are distinct from each other. Now the problem is that in order to understand that the kind of distinct structure and form we have to understand how organisms are actually generated, and that means understanding how starting with an egg or a bud, the organism goes through a developmental process and ends up as a particular type of species with a particular morphology (shape and features). So the whole problem then is to try to understand the nature of that process. One of the fundamental issues is whether or not you can get more or less any kind of organism, or whether there are constraints. Darwin turned biology into a historical science, and in Darwinism, species are simply accidents of history, they don't have any inherent nature. They are just 'the way things happened to work out' and there aren't any particular constraints that mean it couldn't have all worked out very differently. An example is the structure of the arm and the wings of birds. There is always only bone at the top of the arm, never two, even though two would be very useful to birds, but it's never evolved. So it looks like this is something that simply cannot happen because there is an intrinsic constraint on that process. Now there is plenty of evidence that that kind of constraint exists through the whole of biology. In other words, the reason why species are distinct is because you have only got certain types of forms, that can actually be generated by the developmental process. That really begins to shift the emphasis with respect to how we understand the different species and how they are related to each other.

In order to get a really firm grip on this, we actually need a theory of the whole organism and its transformation. Organisms are organized wholes. That's why they have these constraints. The sort of theory that you need to understand morphogenesis involves understanding the components which organisms are made. You certainly need to know a lot about molecules, but you have to understand how they are put together and what sort of dynamics is involved. Now this is where these new sciences that are called the sciences of complexity come into the picture, where you actually look at the dynamics of complex systems, and see how emergent order arises, in often very unexpected ways. This happens because of what we call the relational order, the relationship between the components. It doesn't matter so much what the components are, what they are made of. The really important thing is the way they interact, and that is what determines the type of order that is going to emerge. Now what I and my colleagues are trying to do is to, in a sense, make a map between the pathways of morphogenesis that are available to species organized in a particular way, like algae or plants or amphibians, and to map that onto taxonomy (classification of species). In other words, it's trying to make sense of what we see in evolution by having a theory of morphogenesis (development of shape and form), and making a map between morphogenesis and taxonomy. So it's turning biology into a rational science rather than a historical science. There is no conflict. Everything that happens has a history, so in a sense all sciences have a historical component, but physics of course also has a very strong rational tradition. The whole point is to try to understand why certain structures are necessary, and this is exactly what we do in physics and the new biology. We are asking why has this particular structure emerged in the biological world and this makes biology much more like physics than the historical science that we got from Darwin.

King:
How does your new model of biology incorporate genetics?

Goodwin: A major problem is that in contemporary Darwinism, organisms are actually reduced to genes and their products. Darwinism has given us a very good theory of inheritance in terms of a theory of the genes, but what it has done is to sacrifice the whole organism, as a real entity, to this reductionism, genetic reductionism. That means that organisms have disappeared as real entities from biology, and that, I think, this is a fundamental scientific error. There's another aspect of this problem which has to do with the way Darwinists explains embryonic development. They say that there is a genetic program that determines the development of an organism. An organism wants to become a newt, say, or a sea urchin. Because it has particular genes, they say, it undergoes a particular embryonic development and that is sufficient, in other words knowing the genes is sufficient to understand the details of the embryonic development, and the emergence of a species with its characteristic form and behavior. That sounds, on the face of it, plausible because we know that mutations actually cause transformation of morphology. Drosophila can have a mutation that transforms a two winged fly to a four winged fly. Now that is a pretty major transformation, and a single gene can do it. So you might say that's the sort of thing that is involved in evolution. Well, you see, the burden of proof then is on the neo-Darwinists to demonstrate exactly how the genes do this. They use the term genetic programming, and it is a metaphor for what happens in a computer, but if you ask them to use a genetic program to generate an organism, they can't do it, and the reasons are very simple. You need to know more than gene products in order to explain the emergence of shape and form in organisms. You actually need a theory, a theory that involves physics, chemistry, forces and spatial organization. You can have complete details about genes and you are not going to be able to explain how development occurs. So I think that is the fundamental test. When Darwinists say to me 'genes are enough', I say 'Show me.'

King:
What are the consequences of Darwinist reductionism?

Goodwin: Let me pick up again this issue of the disappearance of organisms as real entities. Because this really has quite profound consequences. I think that this precipitates a kind of crisis of understanding of living forms. It's an extreme reductionism that makes it impossible for us to understand concepts such as health. Health refers to wholes, the dynamics of whole organisms. We currently experience crises of health, of the environment, of the community. I think they are all related. They are not caused by biology by any means, but biology contributes to these crises by failing to give us adequate conceptual understanding of life and wholes, of ecosystems, of the biosphere, and it's all because of genetic reductionism. That's a pretty heavy charge, but let me just describe some of the consequences of genetic reductionism. Once you've got organisms reduced to genes, then organisms have no inherent natures. Now, in our theory of evolution, species are natural kinds, they are really like the elements, if you like. I don't mean literally, but they have the same conceptual status, gold has a certain nature. We are arguing that, say, a sea urchin of a particular species has a nature. Human beings have a nature. Now, in Darwinism, they don't have a nature, because they're historical individuals, which arise as a result of accidents. All they have done is pass the survival test. The Darwinian theory makes it legitimate to shunt genes around from any one species to any other species: since species don't have 'natures', we can manipulate them in any way and create new organisms that survive in our culture. So this is why you get people saying that there is really no difference between the creation of transgenic organisms, that is moving genes across species boundaries, and creating new combinations of genes by sexual recombination within species. They say that is no different to what is happening in evolution. Well, you know, in my book that's a bit like saying there is no difference between radioactive decay, radioactivity as you find it naturally in Uranium, and using that for nuclear energy. Once you scale something up to a particular level you are into a totally different scene. Now, I think that there are the same problems that arise with respect to creation of transgenics, and the reason is because of the utter unpredictability of the consequences of transferring a gene from one species to another. Genes are defined by context. Genes are not stable bits of information that can be shunted around and express themselves independently of context. Every gene depends upon its context. If you change the context, you change the activity of the gene. There are particular cases where that doesn't appear to happen. You put the human gene into bacteria and you get insulin out, but as you know, there is a recent case in the States where the insulin has actually modified and it's not working properly. And then you have got the problem of genes transferring from one transgenic to a related species, resulting in the problem of ecological meltdown, or ecological change that can be precipitated by the use of transgenic species in agriculture. I'm by no means against biotechnology. I just think that it is something that we have to use with enormous caution in its application. We need stringent safety protocols. Now those are the issues of safety, and they are very serious, because the rhetoric that goes with biotechnology is totally at variance with reality. The biotech companies don't want to face the consequences of this radical unpredictability which comes from the intrinsic complexity of organisms. But there is also this really thorny question of species as natural kinds. And when you transfer genes of one type of organism to another, what are you doing to the nature of the species, the recipient species? Now I think that's a very open question. I don't have a simple answer to this. I just think that it's again, something very serious. It raises ethical issues.

King:
How would those ethical questions look in the light of your alternative model of biology?

Goodwin: There is a particular consequence of the idea that species are 'natural kinds' that, I think, is very important for a new type of science in relation to the living realm. It works like this. If you acknowledge that species are natural kinds, so they have natures, then it becomes possible to consider procedures whereby we can understand those natures, that is we go through a process of qualitative evaluation of the conditions under which those natures are being expressed, and cannot be expressed. Let me just clarify that in relation to some specific examples. We know when our domestic animals are distressed and in pain, when they are happy and so on and so forth. In other words we have spontaneous intuitive ways of evaluating the subjective state of domestic animals. Anybody who has an intimate relationship with an animal knows what its subjective states are. Now I say know, they would claim to know, and it seems perfectly legitimate, that claim. But the whole question now is whether we can turn that into a science of subjective states because that would then compliment the science of objectivity which is the mode of contemporary science. In other words what we would be developing is a science of qualities, of qualitative evaluation of other species, and therefore a method of deciding when organisms are being denied the opportunity to express their natures. And this is clearly extremely relevant to the way we treat not just domestic animals and farm animals, but the rest of living nature. And it's that relationship that we need, in order to heal these various crises of the environment and of health and of community, because we've even lost the concept of human nature. Human nature disappears as a concept from neo-Darwinism, and so life become a set of parts, commodities that can be shifted around. But the moment you recover this notion of nature, you are into a different world and you operate in a different way. Now this I think is a pretty urgent development, developing a science of qualities, and it's something we are engaged in at Schumacher College. It has to be done with groups, because you have to try to develop methods of qualitative assessment that are intersubjective, just in the same way that in conventional science the evaluation of what we call reality is dependent upon intersubjective consensus. We come together and carry out these procedures, like experiments and observations and so on, and come to an agreement,about what constitutes reality and what doesn't. And I think we can have a parallel procedure to that in a science of qualities. I think that that would be a fundamental contribution to this issue of how we treat other organisms and at what point a transgenic would be losing its nature.

King:
How would the new science affect our social theories?

Goodwin: Well, another consequence of this new view of species and evolution is it does shift the metaphors that are used to understand evolutionary processes. In Darwinism, you know, the metaphors are of competition and conflict and survival, and in Dawkins' writing it becomes embodied in the notion of selfish genes. Well, from the perspective of organisms as complex dynamic systems, with natures and trying to understand the ecosystem from the point of view, what you find is that organisms are interacting with each other in all kinds of different ways. They are as co-operative as they are competitive, and a lot of the time they are simply making a living. In other words, it's not this nature red in tooth and claw, with fierce competition and the survivors coming away with the spoils. In fact, species extinction seems to be as much to do with the lottery which comes from the dynamics of complex systems, as from anything else. The whole metaphor of evolution, instead of being one of competition, conflict and survival, becomes one of creativity and transformation. When you take on that perspective and bring that into society then you say, all right, why don't we use those metaphors in our social system as well. The metaphors of just making a living, just getting by. Not getting profits into double figure percentages. Not survival through serious competition, but making a living and sharing. I'm not being Utopian, I'm not saying we are going to share everything, because there has to be a certain conflict and competition. But instead of making that the predominant mode, we say that's only one of the components of a vibrant creative society. And the sciences of complexity are really taking on this character of illuminating what it means to be creative. This concept of life at the edge of chaos. Now that is a pretty dramatic metaphor, but what it means is that you shouldn't have too much order. You shouldn't have too much chaos. Perhaps you should be at the point where you can move backwards and forwards between the two and actually be creatively responsive to circumstance. Now clearly, that model is very attractive, but when you look at the dynamics of those systems, you find that it is not driven by competition.They have a complex dynamic interaction and it's that which produces creativity. So the whole business about intellectual property rights and competition that we have in our society, people justify them saying they happen in nature. That is not what happens in nature at all. Nature as we read it now is a much more complex, coherent and creative type of process than the one we have in our social and economic system. So we can begin to contemplate the use of different metaphors and different instantiations of these biological metaphors. You always have to be careful with metaphors. You can't say this happens in biology, therefore it should happen in society. You have to examine it on its own merits. But I think that there is a lot to be said for a basic reevaluation of the metaphors we use in describing evolution, economics and social change, that is arising out of the new sciences.

For more information on subscribing to GenEthics News, email David King or write:

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The Species Problem

[Originally posted at The New Beginning. The weekend symposium is now over, but there are plans for the papers to be published. See Amy Welborn for links. I didn't know Robert Spaemann was in attendance; his works that are in English translation pertain either to ethics or to the liturgy. I have not read anything by him concerning evolution or science; it would be interesting to see what his perspective is, as I do not think he is a Thomist.]

Pope Benedict XVI is holding a 3-day symposium with his former students; this year's topic? Evolution. I'll be waiting to see if any statements or interviews are published after the symposium is over. I think it would be best for nothing to be said, but undoubtedly someone will offer his perspective. "There is no conflict between religion and science." "The question of evolution is one that deserves special attention and further inquiry." etc. etc.

Amy Welborn's most recent post. Zenit article with Fr. Rafael Pascual providing some comments. Fr. Pascual is dean of philosophy at Regina Apostolorum in Rome, the Legionary university. He concedes the use of the word "science" to modern science and its method and presuppositions. I don't. Good philosophizing is not less certain than "science;" if anything, it is more certain. There are two main questions with respect to evolution -- the historical question, whether it has happened in the past, and the question of mechanism, which is proper to science and philosophy, if we accept the traditional Aristotelian account of science. What agents are involved, what is the sequence of changes and the chain of causes?

As I've stated elsewhere, the problem of species is one that needs to be resolved in a way that addresses the other fundamental questions pertaining to the essence of evolution. What is the problem of species? It is this: how is "species" to be defined within biology? Tied to this problem is the question of whether there are natural stable "kinds" or "types" of living things. One might think that since the word is used so often in theorizing about evolution, that its definition would be clear; however, rather than being clear it has become more obscure.

Eventually I will have to read through the following if I am going to write anything more substantial on the topic.

[Note to self: with respect to terminology one needs to make clear what the difference is between "part" and "structure"--there are various "levels of organization" in complex living things, and the structure of one part is the arrangement of its own component parts relative to one another. Is it necessary that such an arrangement have a useful function (as opposed to one that fulfills a purely aesthetic purpose)? Perhaps at some levels and not at others.]

Richard Blanchette
U. Laval thesis, "The Problem of Classification in Zoology" (pdf)

Thomas Reydon (homepage)
cv
his thesis: Species as Units of Generalization in Biological Science
"Why does the species problem still persist?"
"Monists, pluralists, and biologists"
"Species are individuals--or are they?"
review of David Stamos, The Species Problem: Biological Species, Ontology, and the Metaphysics of Biology

David Stamos (faculty page)
The Species Problem
Darwin and the Nature of Species

David Hull
cv
reviews The Philosophy of Biology: An Episodic History by Marjorie Grene and David Depew
His The Philosophy of Biology

based on Hull's work:
"David Hull's Natural Philosophy of Science"
"Ontology of Evolution: Species, Units, and Levels"

Jody Hey
faculty page
"A Reduction of 'Species' Resolves the Species Problem"
Genes, Categories, and Species
a review of his Genes, Categories, and Species

Marjorie Grene
faculty page
interview
"Aristotle and Modern Biology"
"Recent Work on Aristotelian Biology"
There is a good summary of the species problem in chapter 10 of her book (co-written by David Depew), The Philosophy of Biology: An Episodic History

Ernest Mayr
page at Stephen J. Gould's site (scroll down for some online texts)
page at Edge.com (bio)
excerpt on teleonomy
"What is a species, and what is not?"
"Is Biology an Autonomous Science"
news of his death
Systematics and the Origin of Species
"Ernst Mayr and the modern concept of species" (alt)

Other:
Mortimer Adler, Jacques Maritain?
Problems for Thomists: The Problem of Species (1940)
New York, Sheed & Ward

Not available online, as far as I know, but I probably need to read it just to see what Adler wrote on the subject. Maritain is listed as an author on certain webpages, but have not confirmed that this is so. Perhaps he just wrote the introduction, as "Problems for Thomists" was a series of inquiries written by Adler, in The Thomist? (I should double check and see if this book isn't a collection of articles he wrote for The Thomist.)

Matthew H. Slater, The Metaphysics of Species and Specious Metaphysics
Encyclopedia Brittanica, Philosophy of Biology
Alfred Tauber, Ecology and the Claims for a Science-Based Ethics
Intro to Nature's Purposes

KLI Theory Lab, Philosophy of Biology

Rob Wilson's syllabus; lecture handout
Review of Natural Kinds and Conceptual Change
"Different species problems and their resolution"
"Wittgenstein Solves (Posthumously) the Species Problem"
"The Species Problem" (of unknown quality)
"Antiquarian Musings"
Eric Voegelin


hmm... totally unrelated... Wilfred Sellers, Aristotelian Philosophies of Mind
Whoa, I found Christopher Mirus's thesis online: Aristotle's Teleology and Modern Mechanics