Developmental Constraints

Primatology tells that about seven million years ago a split began in primate evolution, a split that led to chimpanzee and human lineages (the pan-homo split). During these millions of years our human lineage has developed performances that our chimpanzee cousins do not possess, like reflective self-consciousness and language. We present here an evolutionary scenario that proposes a rationale for the pan-homo split. It is based on a pre-human anxiety that may have barred access to self-consciousness for the chimpanzee lineage. (...) The starting point of the scenario is the capability that had our pre-human ancestors for an elementary identification with conspecifics. We consider that the evolution of that capability has led to self-consciousness when identifications with conspecifics brought our ancestors to represent their own entity as existing, like conspecifics were represented. But the same identification process also took place with endangered and dying conspecifics. And this has produced a huge anxiety increase, source of important mental sufferings that our ancestors had to limit. Our hypothesis is that different modes of anxiety limitation have led to the pan-homo split. On one side the chimpanzee lineage would have limited an unbearable mental suffering by stopping the development of identifications with conspecifics, and by this also stopping a possible evolution toward self-consciousness. Such anxiety limitation process has led to today chimpanzees which possess a very limited consciousness of themselves. On the other side, our human lineage would have successfully developed anxiety limitation tools like caring, pleasure, anticipation, communication and imitation. With these tools accelerating the evolution of our lineage toward our human mind. The proposed pan/homo split process complements an existing evolutionary scenario for self-consciousness that has positioned anxiety management as a key contributor to the build-up of our human minds. Such overall perspective makes anxiety management a major source to many of our motivations and mental states, much more than assumed so far. Continuations are proposed for a better understanding about our modes of anxiety limitation (including evil behaviors), and also to introduce a possible evolutionary nature of phenomenal consciousness. (shrink)

The developmental properties of organisms play important roles in the generation of variation necessary for evolutionary change. But how can individual development steer the course of evolution? To answer this question, we introduce developmental channeling as a disposition of individual organisms that shapes their possible developmental trajectories and evolutionary dappling as an evolutionary outcome in which the space of possible organismic forms is dappled—it is only partially filled. We then trace out the implications of the channeling-dappling framework for contemporary debates (...) in the philosophy of evolution, including evolvability, reciprocal causation, and the extended evolutionary synthesis. (shrink)

In identifying intrinsic molecular chance and extrinsic adaptive pressures as the only causally relevant factors in the process of evolution, the theoretical perspective of the Modern Synthesis had a major impact on the perceived tenability of an ontology of dispositional properties. However, since the late 1970s, an increasing number of evolutionary biologists have challenged the descriptive and explanatory adequacy of this “chance alone, extrinsic only” understanding of evolutionary change. Because morphological studies of homology, convergence, and teratology have revealed a space (...) of possible forms and phylogenetic trajectories that is considerably more restricted than expected, evo-devo has focused on the causal contribution of intrinsic developmental processes to the course of evolution. Evo-devo’s investigation into the developmental structure of the modality of morphology – including both the possibility and impossibility of organismal form – has led to the utilisation of a number of dispositional concepts that emphasise the tendency of the evolutionary process to change along certain routes. In this sense, and in contrast to the perspective of the Modern Synthesis, evo-devo can be described as a “science of dispositions.” This chapter discusses the recent philosophical literature on dispositional properties in evo-devo, exploring debates about both the metaphysical and epistemological aspects of the central dispositional concepts utilised in contemporary evo-devo and addressing the epistemological question of how dispositional properties challenge existing explanatory models in evolutionary biology. (shrink)

The presentation proposes to complement an existing development on meaning generation for animals, humans and artificial agents by looking at what could have existed at pre-biotic times and what could be a post-human meaning generation. The core of the approach is based on an existing model for meaning generation: the Meaning Generator System (MGS). The MGS is part of an agent submitted to an internal constraint. The MGS generates a meaning when it receives information that has a connection with the (...) constraint. The generated meaning is used by the agent to implement an action (physical, biological or mental) aimed at satisfying the constraint. The action can be in or out the agent. The purpose of the presentation is to widen the MGS approach in order to reach a coverage for information, constraint and meaning from a pre-biotic level to a possible post-human one. We present the MGS for animals, humans and artificial agents with the corresponding constraints. We then look at what could have been a constraint at a pre-biotic far from thermodynamic equilibrium level. At the other end of the spectrum we look at a possible post-human status with an evolution of a ‘limit anxiety’ human constraint and also with AAs submitted to animal or human type constraints. Such approach links information science with physics, evolution, anthropology, semiotics and human mind. Continuations are proposed. (shrink)

Nach neodarwinistischem Verständnis der Evolution entstehen neue Organismen letztlich durch rein zufällige Mutationsprozesse auf genetischer Ebene. Ihre Überlebenschancen werden dann durch die jeweilig herrschende Umwelt begünstigt oder unterdrückt. Die Evolution ist demnach nur vom reinen Zufall geleitet. Neuere Einsichten aus Entwicklungsbiologie (EvoDevo) und Epigenetik haben unsere Sicht der Evolutionsabläufe jedoch deutlich erweitert. Dabei kommt der Umwelt eine lenkende Rolle zu, der reine Zufall verliert an Bedeutung. Damit lässt sich naturwissenschaftliches Verständnis wieder besser mit herkömmlichen Schöpfungsbildern versöhnen.

Darwin´s Erkenntnis über die Abstammung der Arten durch Mutation und Selektion sind in aller Munde, dass aber darüber im Detail noch viel Unklarheit herrscht, ist weniger bekannt. Es sind Fortschritte der Entwicklungsbiologie, die erst seit wenigen Jahren uns molekulare Erklärungsmuster an die Hand geben, mit denen die Entstehung neuer Arten besser verständlich wird. Es handelt sich um die Aufklärung der Wirkungsweise von Genen und ihren molekularen Produkten, die während der embryonalen Entwicklung von Tier und Mensch dafür sorgen, daß der Organismus (...) sich normal entwickelt. Treten Veränderungen (Mutationen) in einem dieser Mastergene auf, so wird dies zur Missbildung oder gar zum Absterben des betreffenden Embryos führen. Aber in seltenen Fällen kann so auch eine neue Tierart begründet werden. Gerade im Darwin-Jahr werden die Lehrbücher zur Evolutionsbiologie um ein wesentliches Kapitel erweitert. Es ist mit EvoDevo überschrieben und will damit ausdrücken, daß Evolutionary Theory ohne Developmental Biology keinen Sinn macht. Die bisherigen Lücken im Verständnis des Evolutionsgeschehens und die neue Sicht von EvoDevo wird im Folgenden dargestellt werden. (shrink)

Bei der Suche nach dem rätselhaften Ursprung des Phänomens „Leben“ wird hier zunächst die zelluläre Ebene betrachtet. Im Grundaufbau zeigen alle Zellen viel Konstantes, aber gleichzeitig stellt jede Zelle ein einmaliges Individuum dar. Leben von Zellen gibt es nur als gegenseitiges Wechselspiel mit ihrer jeweiligen Umwelt. Das Genom (die Gesamtheit aller Gene) bleibt ab der Befruchtung in jeder Zelle eines Individuums konstant. Aber auch die Verwirklichung der Gene braucht eine „molekulare Umwelt“, besonders die vom Muttertier vorbereitete Umwelt im Zytoplasma des (...) Eies. Individualität eines Organismus (z.B. des Menschen) wird also nicht allein vom Genom festgelegt, sondern ist durch Entwicklungsprozesse bedingt (braucht Zeit!). „Leben“ kann (muß?) somit begriffen werden als ein wechselseitiges Kontinuum, welches alle Individuen, alle Spezies und alle Generationen miteinander und ihren Umwelten verbindet. Wie phylogenetisch betrachtet die allererste Zelle aus abiotischen Umständen entstehen konnte, wird hier nicht behandelt. Das Gesagte legt allerdings nahe, dass es nicht Gene waren, die sich eine belebte Welt erschufen, sondern bestimmte (Um-)Welten „erschufen“ sich Gene, die „lebenstauglich“ waren. (shrink)

Background: One of the all-time questions in evolutionary biology regards the evolution of organismal shapes, and in particular why certain forms appear repeatedly in the history of life, others only seldom and still others not at all. Recent research in this field has deployed the conceptual framework of constraints and natural selection as measured by quantitative genetic methods. Scope: In this paper I argue that quantitative genetics can by necessity only provide us with useful statistical sum- maries that may lead (...) researchers to formulate testable causal hypotheses, but that any inferential attempt beyond this is unreasonable. Instead, I suggest that thinking in terms of coordinates in phenotypic spaces, and approaching the problem using a variety of empirical methods (seeking a consilience of evidence), is more likely to lead to solid inferences regarding the causal basis of the historical patterns that make up most of the data available on phenotypic evolution. (shrink)

The purpose of this paper is to present a critique of the current view that reduces cancer to a cellular problem caused by specific gene mutations and to propose, instead, that such a problem might become more intelligible, if it is understood as a phenomenon that results from the breakdown of the morphological plan or Gestalt of the organism. Such and organism, in Aristotelian terms, is characterized for presenting a specific morphe or logos (form) and for having a telos (end) (...) to fulfill. A malignant tumor represents an entity separated from both the organic logos and the organic telos. According to the basic postulates of Semiophysics – a blend of Aristotelian physics and Catastrophe Theory developed by René Thom – an organism is a source (original) form individuated by a dominant pregnance that corresponds to its morphogenetic field. Here it is suggested that cancer in aged individuals might result from the progressive exhaustion of developmental constraints that regulate the process of ontogeny, that it is expected to go from the fertilized non-differentiated zygote to the mature fully developed organism, because there is no further point ahead in the developmental pathway past the reproductive age. Cancer in young individuals (before their reproductive maturity) may then be consequence of the premature derangement of such fundamental developmental constraints. In all cases the result is the loss of morphological coherence within the organism. Thus representing a conflict between an organized morphology (the organism) and a part of such a morphology that drifts towards an amorphous state (the tumor). (shrink)

Following from my criticisms of Calcott’s analysis on the permissive/instructive distinction, I rebut his claims that 1) he clarifies my measure one-to-one specificity; 2) for all intents and purposes of his analysis his notion of precision is different from my measure of one- to-one specificity; 3) Waddington box is a better and different model than the extension of Woodward’s radio I propose.

A descriptive role is suggested for uracil as a temporal divide in the immediate aspects of metabolism verses long term maintained genetic transmission. In particular, details of the mechanism of excision repair of uracil from DNA based on differential parameters of spatial distortion of the planar uracil molecule within the DNA helix verses RNA, when viewed in analogy to a proposed model for space involving the substitution of the act of mirroring for the element of time in processes and a (...) descending complexity of structure with time of evolution, suggest the possibility that negative selection against decreased lifetime is the singular motive force of natural selection. The geometry of the Mobius strip, as it has a plane of mirroring symmetry, a twist able to account for torque in nature, an inversion of inside and out seen in biological structures, and an endless surface that can be accommodated to an atemporal account of physical processes is employed in a holistic model to elaborate a negative selection opposing death as zero volume or the logical existence of physical constraint to volumes that is represented as the ubiquitous inability of witnessing objects of any type to witness simultaneously both a self reflection and the reflection of self reflection. A role for uracil and its’ physical structure, in a model in which both are evolved from the mirroring of events of the witnessing of energies, is elaborated in which temporal aspects such as those entailed in existing models of natural evolution are considered inappropriate in perspectives that are oriented positively towards a successful comprehension of processes; focus is placed instead upon the geometry and arrangement of physical spaces. (shrink)