Are the G?del incompleteness theorems limitative results for the neurosciences?

There are many kinds of limitative results in the sciences, some of which are philosophical. I am interested in examining one kind of limitative result in the neurosciences that is mathematical—a result secured by the Gödel incompleteness theorems. I will view the incompleteness theorems as independence results, develop a connection with independence results in set theory, and then argue that work in the neurosciences (as well as in molecular, systems and synthetic biology) may well avoid these mathematical limitative results. In showing this, I argue that demonstrating that one cannot avoid them is a computational task that is beyond the computational capacities of finitary minds. Along the way, I reformulate three philosophical claims about the nature of consciousness in terms of the Gödel incompleteness theorems and argue that these precise reformulations of the claims can be disarmed.     

A clash of traditions: the history of comparative and experimental embryology in Sweden as exemplified by the research of Gösta Jägersten and Sven Hörstadius

Until the 1940s research traditions were often imported from Germany to Sweden, and young scientists went to German universities to learn new techniques and get in touch with the latest ideas. In developmental biology, the comparative, phylogenetic embryology advocated most forcefully by Ernst Haeckel co-existed with the “Entwickelungsmechanik” tradition developed by Wilhelm His, Wilheln Roux and others partly as a reaction to Haeckel’s ideas. I use the zoology department at Uppsala University as a microcosmos to reflect the tensions between these traditions: Gösta Jägersten (1903–1993) and Sven Hörstadius (1898–1996) are used as exemples. Jägersten was a marine biologist who worked on the morphology and evolution of invertebrates, especiallly their larval forms. He developed a comprehensive theory describing the evolution of the life cycle in early metazoans. Recapitulation was an important ingredient, and Jägersten explicitly based his reasoning on Ernst Haeckel’s “biogenetic law”. Jägersten developed Haeckel’s “Gastraea” theory into another hypothetical animal—Bilaterogastraea—that came into being when the holopelagic Blastaea settled on the ground as an adult and kept a pelagic, planktonic larval form. This was the birth of the pelago-benthic life cycle, which plays such an important role in Jägersten’s speculations on the deep phylogeny of metazoans. Sven Hörstadius was a leading experimental embryologist in the mid-twentieth century. His most important work was on the determination and differentiation of the sea urchin embryo. Early work inspired by his teacher John Runnström’s double gradient theory showed that gradients of animalness (ectodermal determination) and vegetalness (endodermal determination) existed in the 16- and 32- cell embryos. Hörstadius became famous for his elegant extirpation and transplantation experiments using glass needles, and for his microsugical skills. He also made important contributions to the study of cranial neural crest development in the Mexican axolotl, in collaboration with his student Sven Sellman. Hörstadius was the great experimentalist, but did not develop speculative hypotheses the way Jägersten did. The very different styles of scientific research might have played a role also in the development of the personal difficulties that existed for a long time between the two professors.     

Besprechungen

Book reviewed in this article: Manwell , Reginald D. (1968): Introduction to Protozoology Kugler , Hans (1970): Blütenökologie Hölldobler , Bert (1969): Orientierungsmechanismen dcs Ameisengastes Atemeles Grzimeks Tierleben Band 9, Vögel 3 Curry-Lindahl , Kai (1970): Breeding Biology of the Baltic Seal Le Boeuf , Burney J., und Richard S. Peterson Nachtsheim , Hans (1970): Vergleichende Betrachtungen zum Übervölkerungsproblem bei Säugetier und Mensch Hass , Hans (1970): Energon, das verborgene Gemeinsame Berggren , Sigvard (1969): Mein Tierparadies Grzimek , Hildegard (1970): In meinem Herzen haben viele Tiere Platz     

Taxon names as paradigms: the structure of nomenclatural revolutions

In the present paper I argue that the two systems of phylogenetic nomenclature hitherto proposed represent, in a generalized sense, two different philosophies for how science develops and progresses. The phylogenetic system of definition initially proposed by de Queiroz and Gauthier [Syst. Zool. 39 (1990) 307], and later labeled PSD, is typically Popperian in the sense that science progresses toward truth by an accumulation of knowledge. Phylogenetic definitions of taxon names are assumed to adapt automatically to each new hypothesis of phylogeny, thereby reflecting better and better hypotheses. The phylogenetic system of reference proposed by Härlin [Zool. Scr. 27 (1998a) 381], on the other hand, is more Kuhnian, because it is built on the idea that successive hypotheses are incommensurable (and thus not cumulative) and that taxon names might be equalled with low‐level paradigms.     

Ein bakterielles Kulturfiltrat mit antiphytoviraler Aktivität an Gurke/Gurkenmosaik-Virus (cucumber mosaic virus) und Tabak/Tabakmosaik-Virus (tobacco mosaic virus): (Kurze Mitteilung)

Es wurde die Intra‐ und Interpopulationsvariation untersucht, die durch Adaptationsreaktionen der Individuen (Klone) der Gemeinen Quecke (Elytrigia repens (L.) DESV.) am Versuchsort zum Ausdruck kommt. Die Klone stammten aus Populationen verschiedener Höhenlagen vom Territorium der östlichen Bundesländer Deutschlands. Die Ergebnisse zeigen, daß sich die Populationen in der Variabilität der Enzymaktivität (saure Phosphatase, Peroxidase, Polyphenoloxidase) sowie in der Variabilität der Isoenzymmuster (Peroxidase, Esterase) unterscheiden. Die höchste Variabilität der genannten Parameter wurde für Populationen nachgewiesen, die aus einer Höhenlage von ca. 400 m ü. NN stammten. Ausgehend von 400 m ü. NN nimmt die Variabilität in Richtung größerer und niedrigerer Höhenlagen von 400 m hin ab. Die Variabilitätsunterschiede, die unter gleichen Bedingungen nachgewiesen wurden, weisen auf die Existenz eines Zusammenhanges zwischen den typischen Adaptationsreaktionen von Populationen und der Gesamtheit der Selektionsfaktoren des natürlichen Milieus hin, von dem sie stammten. Es gibt einen Zusammenhang zwischen der nachgewiesenen Variabilität und der Überlebensrate nach einer Adaptationsdauer von fünf Jahren.     

Die Vegetationszonierung der Neotropis und ihr Wandel seit der Eiszeit

• 1 . Die physiognomisch-ökologische Höhenstufung der Vegetation in den Tropen wird maßgeblich von den Eigenschaften der vertikalen Temperatur- und Niederschlagsbedingungen geprägt.
• 2 . Das Temperaturhöhenprofil in seiner Wirkung auf die Vegetation entspricht in den nordhemisphärischen Randtropen (Mexiko) nur noch in abgeschwächter Form der Tropennorm.
• 3 . Die Mischung der Florenreiche unterliegt in den Randtropen (Mexiko) einer Steuerung durch außertropische Klimaeinflüsse. Doch bleibt die hygrische Höhenstufung in ihrer Wirkung auf die vertikale Vegetationsanordnung voll erhalten.
• 4 . Der Klimawandel seit der Eiszeit war auch in den Tropen wirksam und hat namentlich die Vegetationsgliederung differenziert beeinflußt.

• a) In den inneren Tropen führt der stärkere Temperaturgradient mit der Höhe und die damit verbundene Veränderung der Feuchtigkeitsverhältnisse zu einer Oszillation der einzelnen Vegetationsstufen. Dabei wurde die Waldgrenze in der hochglazialen Phase gegenüber heute abgesenkt, in der postglazialen Wärmezeit leicht angehoben.
• b) . In den Randtropen gab es nicht nur eine vertikale, sondern auch eine horizontale Verschiebung der Vegetationsgrenzen.

• 5 . Nach der postglazialen Wärmezeit hat sich der waldlose Höhenbereich durch Rückgang der Temperatur und Veränderung im Niederschlagsregime in Verbindung mit menschlichem Einfluß hangabwärts vergrößert; die Waldgrenze wurde erneut leicht abgesenkt.
• 6 . Trockeneres Klima während des letzten Hochglazials um ca. 18 000 v. h. hat nicht nur die Höhenregionen der Tropen, sondern auch Teile der tropischen Niederungswälder betroffen und ihren Umfang zugunsten trockener Formationen verringert.
• 7 . Die postglaziale Wärmezeit war in den Tropen mit höherer Feuchtigkeit verbunden und begünstigte eine schwache Ausbreitung der Tropenwälder in den Niederungen und an der oberen Waldgrenze.
• 8 . Der im späten Holozän in der langfristigen Bilanz wieder eintretende Austrocknungsprozeß wurde bis zur Gegenwart durch das Einwirken des Menschen verstärkt.

     

The semantic approach to evolutionary theory

Paul Thompson, John Beatty, and Elisabeth Lloyd argue that attempts to resolve certain conceptual issues within evolutionary biology have failed because of a general adherence to the received view of scientific theories. They maintain that such issues can be clarified and resolved when one adopts a semantic approach to theories. In this paper, I argue that such conceptual issues are just as problematic on a semantic approach. Such issues arise from the complexity involved in providing formal accounts of theoretical laws and scientific explanations. That complexity is due to empirical and pragmatic considerations, not one's adherence to a particular formal approach to theories. This analysis raises a broader question. How can any formal account properly represent the complex nature of empirical phenomena?     

What could arsenic bacteria teach us about life?

In this paper, I discuss the recent discovery of alleged arsenic bacteria in Mono Lake, California, and the ensuing debate in the scientific community about the validity and significance of these results. By situating this case in the broader context of projects that search for anomalous life forms, I examine the methodology and upshots of challenging biochemical constraints on living things. I distinguish between a narrower and a broader sense in which we might challenge or change our knowledge of life as the result of such a project, and discuss two different kinds of projects that differ in their potential to overhaul our knowledge of life. I argue that the arsenic bacteria case, while potentially illuminating, is the kind of constraint-challenging project that could not—in spite of what was said when it was presented to the public—change our knowledge of life in the deeper sense.     

The Mechanism of TC230′s Thermostability: A Molecular Dynamics Simulation Study

Abstract

The quasielastic neutron scattering index β and the modulus of a protein's quasi-electric dipole moment were utilized to quantitate the thermostability of wildtype TC230 and its mutants. Charged residues Arg314, Glu246, Glu291, and some prolines near the C-terminus of the sequence (Pro228, Pro296, and Pro308) were identified to be critical for the thermostability of wildtype TC230 according to these two criteria. By analyzing the molecular conformation changes during the simulation, it was demonstrated how the mutant P228S was destabilized by disrupting two salt-bridges Asp1160Dl-Lys215N and Glu2100El-Lys217N at an adjacent β-turn. The destabilization of P296S also shown to be intimate correlated with the break down of ion pair Lysl88N-Glu2910El. The sensitivity of its electrostatic network to the local structure is an important feature. It reveals that the ‘proline effect’ and electrostatic interactions together influences the thermostability of TC230 a lot.     

Do Organisms Exist?

What is the status of organisms in modern evolutionary biology?I argue that this is a question which centers on the questionof reduction, and towards a complete answer, I pursue issuesthrough three different senses of the term: ontological, methodological,and epistemological. The first sense refers to the ultimatestatus of the entities of the organic world, and in this senseI argue that organisms have no special status. The second senserefers to the question of organization, and I argue that inthe light of modern evolutionary biology organisms do have adistinctive "design-like" organization. The third sense refersto the relationship between theories, in particular to whetherthe theories of the biological sciences can be shown to be logicalconsequences of the theories of the physical sciences. I arguethat such reduction may be possible in principle but difficultin practice. However, from the perspective of the working scientist,this hardly matters. In conclusion, I argue that in some respectsorganisms are not distinctive and in other respects they are.Certainly biologists need not worry for the autonomy of theirsubject.     

Selective "death programs" or pleiotropic"life programs"? Looking for programmed cell death in the light of evolution

"Nothing in biology makes sense except in the light of evolution", wrote Theodosius Dobzhansky, one of the founders of the Modern Synthesis that led to the unification of evolutionary theory and genetics in the midst of the 20th century. Programmed cell death is a genetically regulated process of cell suicide that is central to the development, homeostasis and integrity of multicellular organisms. Conversely, the dysregulation of mechanisms controlling cell suicide plays a role in the pathogenesis of a wide range of diseases. While great progress has been achieved in the unveiling of the molecular mechanisms of programmed cell death, a new, and somehow puzzling level of complexity has recently begun to emerge, suggesting i) that several different self destruction pathways may exist and operate in parallel in our cells, and ii) that molecular effectors of cell suicide might also perform other functions unrelated to cell death induction and crucial to cell survival, such as cell differentiation, metabolism, and the regulation of the cell cycle. These new findings, with important physiopathological and therapeutic implications, seem at odds with the paradigm of programmed cell death derived from the studies of Caenorhabditis elegans, which led to the concept of the existence of selective, bona fide death genes that emerged and became selected for their sole capacity to execute or repress cell death. In this review, I will argue that this new level of complexity might only make sense and be understood when considered in a broader evolutionary context than that of our phylogenetic divergence from C. elegans. A new view of the regulated cell death pathways emerges when one attempts to ask the question of when and how they may have become selected during a timeline of 4 billion years, at the level of ancestral single-celled organisms, including the bacteria. I will argue that there may be no such thing as a bona fide genetic cell death program. Rather, in the framework of a model that I have termed the "original sin" hypothesis, I have proposed the existence of an initial pleiotropy of the molecular tools involved in the control and execution of self-destruction--an ancestral involvement in both pro-life and pro-death activities. I will discuss how this hypothesis may be reconciled with the C. elegans paradigm of programmed cell death. Finally I will discuss how an ancestral level of pleiotropic functions of the molecular tools involved in the control of cell death, aging and genetic diversification might have favored their initial selection, their constant availability for de novo selection, and their progressive propagation in most--if not all--species during the course of evolution.     

Die energetische Verwertung der Futterstoffe

Abstract

Feeding broiler chicks on graded levels of fluorine (0, 25, 125, 625 and 3125 ppm F) from NaF for 4 weeks (4–7 weeks of age) resulted in various alterations which depended on the level of contamination. The main changes included poor growth and feed conversion, high mortality rate, disorders of bone formation, decreased relative weights of pituitary, adrenal, heart, liver, spleen, lungs, kidneys and gizzard and changes in intestinal dimensions. Also, the biochemical tests revealed other kinds of physiological disfunction mainly in the form of anaemia (low haematocrit, haemoglobin, total protein, albumin and globulin fractions), intoxication (increased methaemoglobin), nephrotic (raised phosphorus and magnesium) and hepatic (elevated lipoproteins and lowering enzymatic activity) disfunctions. The general observations and postmortem examination confirmed also the biochemical findings which revealed the harmful effect of feedborne-fluorine intoxication in broiler chicks.

Die Fütterung von Broilerküken mit abgestuften Fluorniveaus (0, 25, 125, 625 und 3125 mg F/kg Futter) aus NaF über 4 Wochen führte zu verschiedenen Veränderungen, die von der Höhe der Kontamination abhingen. Wesentliche Veränderungen betrafen ein schlechtes Wachstum und einen niedrigen Futteraufwand, eine hohe Sterblichkeitsrate, Unregelmäßigkeiten bei der Knochenbildung, eine verminderte relative Masse von Hypophyse, Nebennieren, Herz, Leber, Milz, Lungen, Nieren und Magen sowie Veränderungen von Länge und Durchmesser der Därme. Darüber hinaus zeigten die biochemischen Untersuchungen physiologische Funktionsstörungen, hauptsächlich in der Form von Anämie (niedrige Werte für Hämatokrit, Hämoglobin, Gesamtprotein sowie Albumin- und Globulin-fraktionen), Vergiftungen (erhöhter Methämoglobinspiegel), Nierendysfunktion (erhöhter Phosphor- und Magnesiumgehalt) und Leberdysfunktion (erhöhter Lipoproteingehalt und verminderte Enzymaktivität). Die allgemeine Beobachtung und die Untersuchung nach der Schlachtung bestätigten ebenfalls die Ergebnisse der biochemischen Untersuchungen, die den negativen Effekt der Fluorvergiftung aufzeigte.     

Bacterial communication

Biology & Philosophy - On the basis of findings from developmental biology, some researchers have argued that evolutionary theory needs to be significantly updated. Advocates of such a...     

New Books

Factor , J. R. (ed) 1995: Biology of the lobster Homarus americanus. Hölldobler, B. & Wilson, E. O. 1995: Ameisen. Terman , M. R. 1996: Messages from an owl. Williams , T. D. 1995: The penguins. With contributions by R. P. Wilson , P. D. Boersma & D. L. Stokes . Leyhausen , P. 1996: Katzenseele. Wesen und Sozialverhalten. Alterman, L., Doyle, G. A. & Izard , M. K. (eds) Heymer, A. 1995: Die Pygmäen. Menschenforschung im afrikanischen Regenwald.     

Notes from a snail island: Littorinid evolution and adaptation

The most successful study systems are built on a foundation of decades of research on the basic biology, ecology and life history of the organisms in question. Combined with new technologies, this can provide a formidable means to address important issues in evolutionary biology and molecular ecology. Littorinid marine snails are a good example of this, with a rich literature on their taxonomy, speciation, thermal tolerance and behavioural adaptations. In August 2017, an international meeting on Littorinid evolution was held at the Tjärnö Marine Research Laboratory in Western Sweden. In this meeting review, I provide a summary of some of the exciting work on parallel evolution, sexual selection and adaptation to environmental stress presented there. I argue that newly available genomic resources present an opportunity for integrating the traditionally divergent fields of speciation and environmental adaptation in Littorinid research.     

Rebuilding ships while at sea—Character individuality,homology, and evolutionary innovation

How novel traits originate in evolution is still one of the most perplexing questions in Evolutionary Biology. Building on a previous account of evolutionary innovation, I here propose that evolutionary novelties are those individualized characters that are not homologous to any characters in the ancestor. To clarify this definition, I here provide a detailed analysis of the concepts of “character individuality” and “homology” first, before addressing their role for our understanding of evolutionary innovation. I will argue (1) that functional as well as structural considerations are important for character individualization; and (2) that compositional (structural) and positional homology need to be clearly distinguished to properly describe the evolutionary transformations of hierarchically structured characters. My account will therefore integrate functional and structural perspectives and put forward a new multi-level view of character identity and transformation.     

Reviews

Book reviewed in this article: Archer , J. (1988): The behavioral biology of aggression (Biologische Grundlagen aggressiven Verhaltens) Cube , F. von (1988): Besiege deinen Nächsten wie dich selbst. Aggression im Alltag (Conquer your fellowman as you conquer yourself. Aggression in everyday life). Lewontin , R. C., S. Rose , & L. J. Kamin (1988): Die Gene sind es nicht … Biologie, Ideologie und menschliche Natur (It's not the genes … Biology, ideology and human nature). Gould , S. J. (1988): Der falsch vermessene Mensch (The mismeasure of man. W. W. Norton & Co., New York 1981, deutsche Originalausgabe bei Birkhäuser, Basel 1983). Taylor , R. B. (1988): Human territorial functioning. An empirical, evolutionary perspective on individual and small group territorial cognitions, behaviors, and consequences (Entstehung und Bedeutung von Territorialfunktionen für Einzelmenschen und kleine Gruppen). Lindauer , M., & A. Schöpf, eds. (1987): Die Erde unser Lebensraum. Überbevölkerung und Unterbevölkerung als Probleme einer Populationsdynamik (Problems of population dynamics in man). Böhm , W., & M. Lindauer, eds. (1988): ?Nicht Vielwissen sättigt die Seele”. Wissen, Erkennen, Bildung, Ausbildung heute (Knowledge and education). Rahmann , H., & M. Rahmann (1988): Das Gedächtnis. Neurobiologische Grundlagen (Neurobiological basis of memory).     

Einfluss langdauernder Überflutungen auf die Stoffproduktion von Glanzgraswiesen

Es sind die Ergebnisse der Stoffproduktion-Analysen vonPhalaris arundinacea-Beständen im Hinblick auf die hydrologischen Bedingungen der Jahre 1965 und 1966 angegeben. Die Analysen wurden auf den Standorten dreier Stufen der Orlice-Flussaue (NO-Böhmen) durchgeführt, die sich von einander durch die Dauer der Überflutung, der Höhe der Hoch-wassersäule sowie durch den Verlauf des Erosions-Akkumulationsprozesses unterscheiden. In der Zeit vom 1. IV. bis 30. VI. 1965 war die untere Stufe der Flussaue (Zone I) während 91 Tagen, die mittlere Stufe der Flussaue (Zone II) während 55 Tagen und die obere Stufe der Flussaue (Zone III) während 20 Tagen überflutet. Mitte Juli 1965 betrug die oberirdische Nettoproduktion in der Zone I 65,47±3.6,89 g/m², in der Zone II 245,84±3.17,44 g/m², in der Zone III 1443,05±3.70,69 g/m². Im Frühjahr 1966 waren die Bestände nur kurzfristig überflutet. Die oberirdische Juli-Nettoproduktion in der Zone I, II und III betrug 1277,61±3.99,00g/m², 1480,63±3.68,57 g/m² und 1954,63±3.124,21 g/m².     

Thirty years of <Emphasis Type="Italic">Biology &amp; Philosophy:</Emphasis> philosophy of which biology?

Which domains of biology do philosophers of biology primarily study? The fact that philosophy of biology has been dominated by an interest for evolutionary biology is widely admitted, but it has not been strictly demonstrated. Here I analyse the topics of all the papers published in Biology & Philosophy, just as the journal celebrates its thirtieth anniversary. I then compare the distribution of biological topics in Biology & Philosophy with that of the scientific journal Proceedings of the National Academy of Science of the USA, focusing on the recent period 2003–2015. This comparison reveals a significant mismatch between the distributions of these topics. I examine plausible explanations for that mismatch. Finally, I argue that many biological topics underrepresented in philosophy of biology raise important philosophical issues and should therefore play a more central role in future philosophy of biology.     

Wachstum und Bildung extrazellulärer Polysaccharide in Batch-Kulturen von Porphyridium aerugineum,Rhodophyceae

An batch-Kulturen von P. aerugineum im Algen-Lichtthermostaten und in 5-Liter-Rohren mit Innenbeleuchtung wurde der Einfluß einzelner Nährlösungskomponenten (SO₄-, Mg- und Mn-Gehalt, Tricin- und Tris-Puffer, pH-Wert), sowie von Beleuchtungsstärke und Durchlüftungsintensität auf das Wachstum und auf die Bildung extrazellulärer Polysaccharide untersucht. Beide Prozesse werden durch diese Faktoren verschieden und teils gegensinnig beeinflußt. Als Maß für die Produktion extrazellulärer Polysaccharide diente die Viskosität der Algensuspensionen, für die Wuchsleistung das Trockengewicht. Die für die Bildung extrazellulärer Polysaccharide optimale Sulfatkonzentration der Nährlösung ist doppelt so hoch als die für optimales Wachstum benötigte. Sehr viskose Suspensionen ergeben sich, wenn die molare Mg-Konzentration nur die Hälfte der SO₄-Konzentration des Mediums beträgt. Einseitige Erhöhung der Mg-Konzentration fördert das Wachstum, mindert aber die Bildung extrazellulärer Polysaccharide erheblich. Stark viskositätssenkend bei unverminderter Wuchsleistung wirkt eine Erhöhung des Mn-Gehaltes der Nährlösung. Eine spezifisch viskositätsfördernde Wirkung über die pH-Wirkung hinaus kommt dem Tricingehalt des Mediums zu. Bemerkenswert ist auch das hohe Beleuchtungsoptimum von P. aerugineum. Besonders hohe Wuchsleistungen bei intensiver Produktion extrazellulärer Polysaccharide wurden in den stark belüfteten 5-Liter-Rohren mit Innenbeleuchtung erzielt. Die Ergebnisse werden auch in Hinblick auf eine Möglichkeit zur Gewinnung von gallertigen Wandsubstanzen für industrielle Zwecke diskutiert.