Mechanism and vitalism. A history of the controversy

This is an attempt to interpret the history of mechanism vs. vitalism in relation to the changing framework of culture and to show the interrelation between both these views and experimental science. After the scientific revolution of the seventeenth century, causal mechanism of classical physics provided the framework for the study of nature. The teleological and holistic properties of life, however, which are incompatible with this theory yielded — as a result both of internal developments within biology and of a general reaction against dogmatic rationalism — to a vitalistic interpretation of life which ascribed a mysterious force to living organisms. It will be shown that both mechanism and vitalism are related to the experimental climate of the time in which they were popular. The controversy has now lost its raison d'être as a result of the development of the theory of systems and of a better understanding of the chemistry and evolution of life.     

The influence of German idealistic morphology on the development of C.J. van der Klaauw's epistemology

Notwithstanding the general rise of experimental disciplines in biology in the first decades of our century, in Germany and in the Netherlands the interest in the idealistic morphological tradition flourished, and compensated for a reductionistic causal approach to natural phenomena. This article analyses the influence of the German idealistic morphologists W. Lubosch and A. Meyer on the development of C.J. van der Klaauw's epistemology. It discusses the gradual incorporation of non-causal principles into van der Klaauw's concept of biology. Van der Klaauw's epistemological concept of holistic biology was shaped in a critical confrontation with German idealistic morphology, and his early considerations can be interpreted as a direct impulse towards the development of his theory of functional components. Van der Klaauw's theories, being an alternative to the reductionistic experimental sciences, were among the causes of the fact that in the first half of our century biology in the Netherlands took a course deviating from the development of biology in the Anglo-American countries.     

H. A. GLEASON'S 'INDIVIDUALISTIC CONCEPT' AND THEORY OF ANIMAL COMMUNITIES: A CONTINUING CONTROVERSY

A tradition of natural history and of the lore of early twentieth-century ecology was that organisms lived together and interacted to form natural entities or communities. Before there was a recognizable science of ecology, Mobius (1877) had provided a name ‘biocoenosis’ for such entities. This concept persisted in the early decades of ecological science; at an extreme it was maintained that the community had integrating capabilities and organization like those of an individual organism, hence the term organismic community. In the 1950s- 1970s an alternative individualist concept, derived from the ideas of H. A. Gleason (1939), gained credence which held that communities were largely a coincidence of individualistic species characteristics, continuously varying environments and different probabilities of a species arriving on a given site. During the same period, however, a body of population based theory of animal communities became dominant which perpetuated the idea of patterns in nature based on biotic interactions among species resulting in integrated communities. This theory introduced an extended terminology and mathematical models to explain the organization of species into groups of compatible species governed by rules. In the late 1970s the premises and methods of the theory came under attack and a vigorous debate ensued. The alternatives proposed were, at an extreme, null models of random aggregations of species or stochastic, individualistic aggregations of species, sensu Gleason. Extended research and debate ensued during the 1980s resulting in an explosion of studies of animal communities and a plethora of symposia and volumes of collected works concerning the nature of animal communities. The inherent complexity of communities and the traditional differences among animal ecologists about how they should be defined and delimited, at what scale of taxa, space and time to study them, and appropriate methods of study and analysis have resulted in extended and as yet inconclusive discussions. Recent differences and discussions are considered under five general categories, evolution and community theory, individualistic concept, community definition, questions from community ecology and empirical studies. Communities are seen by some ecologists as entities of coevolving species and, in any case, it is necessary to integrate evolutionary ideas with the varied concepts of community. The individualistic concept of community, as a relative latecomer to discussions of animal community, is sometimes misconstrued as holding that communities are random assemblages of organisms without biotic interactions among species. Nevertheless, it has increasingly been accepted as supported by studies of diverse taxa and habitats. However, many other ecologists continue to argue for integrated, biotically controlled and evolved communities. Among the major difficulties of addressing the problems of community are problems of definition and terminology. One commentator noted that community ecology may be unique in the sciences because there is no consensus definition of community. One consequence of the lack of consensus definition is evident in the varied and diffuse questions posed in studies of community. Some critics of community ecology fault it for posing unanswerable questions. Recent empirical studies include various assessments about community ranging from deterministic, integrated and organismic to individualistic with various suggestions for compromise. The early emphasis on birds in studies of animal communities has expanded to obviate the argument that any position is constrained by the taxon studied. Insects, in general, are more prone to give rise to interpretation of a nonintegrated community. Parasite community studies have given rise to some distinctive categories and terminology. However, consensus is not achieved either within or among taxonomic groups or habitat groups. The extreme heterogeneity and complexity of communities (and of ecologists) has produced extended discussions of how to approach such multidimensional complexity. These discussions often turn on polarized positions of reductionism and experiment versus holism. Proponents of reductionism asserted that natural communities cannot be understood or their structure and organization predicted until experimental communities, or models thereof, are understood. Holists insisted that the inherent complexity and variability of communities cannot be elucidated in simplified experimental communities or in models. A more recent trend has urged pluralism, or, at least, mutual respect and dialogue, which are sometimes lacking, between proponents of these divergent approaches to communities. Recent work perpetuates the original dichotomy between integrated organismic community concept and individualistic non-integrated concept. The hope for a rule-governed community has extended to metarules and a new theory of community as divided into core species and satellite species is called into question. The problems of distinguishing between determinism and chance effects in community organization continue and the lost or fading hope of a general theory of community is revived in a search for rules that govern their assembly.     

Natural selection and the conditions for existence: representational vs. conditional teleology in biological explanation

Human intentional action, including the design and use of artifacts, involves the prior mental representation of the goal (end) and the means to achieve that goal. This representation is part of the efficient cause of the action, and thus can be used to explain both the action and the achievement of the end. This is intentional teleological explanation. More generally, teleological explanation that depends on the real existence of a representation of the goal (and the means to achieve it) can be called representational teleological explanation. Such explanations in biology can involve both external representations (e.g., ideas in the mind of God) and internal representations (souls, vital powers, entelechies, developmental programs, etc.). However, another type of explanation of intentional action (or any other process) is possible. Given that an action achieving a result occurs, the action can be explained as fulfilling the necessary conditions (means) for that result (end), and, reciprocally, the result explained by the occurrence of those necessary conditions. This is conditional teleological explanation. For organisms, natural selection is often understood metaphorically as the designer, intentionally constructing them for certain ends. Unfortunately, this metaphor is often taken rather too literally, because it has been difficult to conceive of another way to relate natural selection to the process of evolution. I argue that combining a conditional teleological explanation of organisms and of evolution provides such an alternative. This conditional teleology can be grounded in existence or survival. Given that an organism exists, we can explain its existence by the occurrence of the necessary conditions for that existence. This principle of the 'conditions for existence' was introduced by Georges Cuvier in 1800, and provides a valid, conditional teleological method for explaining organismal structure and behavior. From an evolutionary perspective, the conditions for existence are the range of boundary conditions within which the evolutionary process must occur. Moreover, evolutionary change itself can be subjected to conditional teleological explanation, because natural selection theory is primarily a theory about the relation between the conditions for the existence of organisms and the conditions for the existence of traits in populations. I show that failure to distinguish representational from conditional teleological explanation has confused previous attempts to clarify the relation of teleology to biology.     

Kant’s concept of natural purpose and the reflecting power of judgement

This paper examines how in the ‘Critique of teleological judgment’ Kant characterized the concept of natural purpose in relation to and in distinction from the concepts of nature and the concept of purpose he had developed in his other critical writings. Kant maintained that neither the principles of mechanical science nor the pure concepts of the understanding through which we determine experience in general provide adequate conceptualizations of the unique capacities of organisms. He also held that although the concept of natural purpose was derived through reflection upon an analogy to human purposive activity in artistic production and moral action, it articulates a unique notion of intrinsic purposiveness. Kant restricted his critical reflections on organisms to phenomena that can be given to us in experience, criticizing speculations on their first origins or final purpose. But I argue that he held that the concept of natural purpose is a product of the reflecting power of judgment, rather than an empirical concept, and represents only the relation of things to our power of judgment. Yet it is necessary for the identification of organisms as organized and self-organizing, and as subject to unique norms and causal relations between parts and whole.     

Kant's concept of natural purpose and the reflecting power of judgement

This paper examines how in the 'Critique of teleological judgment' Kant characterized the concept of natural purpose in relation to and in distinction from the concepts of nature and the concept of purpose he had developed in his other critical writings. Kant maintained that neither the principles of mechanical science nor the pure concepts of the understanding through which we determine experience in general provide adequate conceptualizations of the unique capacities of organisms. He also held that although the concept of natural purpose was derived through reflection upon an analogy to human purposive activity in artistic production and moral action, it articulates a unique notion of intrinsic purposiveness. Kant restricted his critical reflections on organisms to phenomena that can be given to us in experience, criticizing speculations on their first origins or final purpose. But I argue that he held that the concept of natural purpose is a product of the reflecting power of judgment, rather than an empirical concept, and represents only the relation of things to our power of judgment. Yet it is necessary for the identification of organisms as organized and self-organizing, and as subject to unique norms and causal relations between parts and whole.     

Linking metacommunity theory and symbiont evolutionary ecology

Processes that occur both within and between hosts can influence the ecological and evolutionary dynamics of symbionts, a broad term that includes parasitic and disease-causing organisms. Metacommunity theory can integrate these local- and regional-scale dynamics to explore symbiont community composition patterns across space. In this article I emphasize that symbionts should be incorporated into the metacommunity concept. I highlight the utility of metacommunity theory by discussing practical and general benefits that emerge from considering symbionts in a metacommunity framework. Specifically, investigating the local and regional drivers of symbiont community and metacommunity structure will lead to a more holistic understanding of symbiont ecology and evolution and could reveal novel insights into the roles of symbiont communities in mediating host health.     

A statistical mechanical treatment of fatty acyl chain order in phospholipid bilayers and correlation with experimental data. A. Theory

A theoretical model has been developed in order to describe the organization of acyl chains in phospholipid bilayers. Since the model is intended to reproduce highly quantitative experimental results such as the deuterium magnetic resonance (NMR) data and to supplement the experimental information, all the rotameric degrees of freedom, the excluded volume interactions and the van der Waals interactions have been considered. The model is a direct extension of a generalized van der Waals theory of nematic liquid crystals to flexible molecules. In this picture, the anisotropy of the short-range repulsive forces which are treated by a hard core potential is introduced as the dominant factor governing intrinsic order among the chains. The anisotropy of the attractive forces, which are approximated by a molecular field, plays a somewhat secondary role. The dependence of the energy of interaction on the relative chain conformations is approximated by two order parameters reflecting respectively the ‘average shape’ of the molecules and the ‘average shape’ in a ‘mean orientation’. The influence of the interactions in the polar region on the lateral chain area is accounted for by an effective lateral pressure. In certain aspects the model has features in common with the Mar?elja theory.     

Resting cysts of someChaetoceros species,identified and figured by A. Van der Werff

This note is dedicated to Albert van der Werff (1903–1991), the Dutch diatom expert, distributing his extended knowledge to numerous students interested in aquatic ecology. His drawings of the resting cysts ofChaetoceros affine Lauder andCh. constrictum Gran, not figured in his diatom flora (van der werff andhuls, 1957–1974), are published and discussed. The figures represent a valuable contribution to taxonomical literature. Publication no. 661 Netherlands Institute of Ecology, Centre for Estuarine and Coastal Ecology, Yerseke, The Netherlands.     

Van der Heijden, M.G.A. and Sanders, I.R. (eds) Microrhizal ecology

In his foreword to the volume, Philip Grime says: ‘Themost significant challenge for ecologists at the present timeis to continue to exploit the many current opportunities forpenetration into detailed mechanisms but simultaneously to activelypromote integration . . . within ecological research.Mycorrhizal ecology is uniquely positioned . . . toprovide a lead.’ The volume, edited by van der Heijdenand Sanders, thus aims to meet the twin needs of scaling up,from detailed molecular science to the ecosystem, and demonstratingthat the plant, as found in nature, is itself a community oforganisms that interact with other such     

Long range intermolecular forces between macroscopic bodies: macroscopic and microscopic approaches.

Van der Waals energies of interaction are calculated by two methods, the macroscopic method of Lifshitz and the microscopic method of London-Casimir and Polder-Hamaker for the case of two semi-infinite slabs separated by a thin film. When retardation effects may be neglected, the London-Hamaker approach yields values of dispersion interactions which almost coincide with those of the Lifshitz approach, the magnitude of the former values being larger by approximately 10–25%, which is attributed to the effect of the molecular environment in condensed media. At 50–100 Å film thicknesses where retardation effects are small, dispersion terms are generally the major part of van der Waals forces in the Lifshitz formulation. Hence, for 50–100 Å film thicknesses the Hamaker approach, which only includes dispersion interactions is generally adequate. By accounting for retardation effects, which significantly reduce the magnitude of dispersion interactions at several hundred Å, there is a reasonable agreement between the values obtained by the macroscopic and microscopic approaches. When polar substances are present and for film thicknesses of several hundred Å, where dispersion interactions are significantly reduced, the major contribution to van der Waals forces may arise from orientation and induction terms. For such cases the Hamaker approach may lead to critical underestimates of the calculated magnitude of van der Waals forces. An ad hoc way to overcome this difficulty which is applicable to any geometry is proposed. This study presents a simple procedure for the determination of free energies of interaction between macroscopic bodies of various shapes. The procedure, which is applicable when the molecules of bodies and surrounding medium are isotropic, yields results which closely approximate those obtained with the Lifshitz theory.     

Van der Waals forces. Special characteristics in lipid-water systems and a general method of calculation based on the Lifshitz theory

A practical method for examining and calculating van der Waals forces is derived from Lifshitz'' theory. Rather than treat the total van der Waals energy as a sum of pairwise interactions between atoms, the Lifshitz theory treats component materials as continua in which there are electromagnetic fluctuations at all frequencies over the entire body. It is necessary in principle to use total macroscopic dielectric data from component substances to analyze the permitted fluctuations; in practice it is possible to use only partial information to perform satisfactory calculations. The biologically interesting case of lipid-water systems is considered in detail for illustration. The method gives good agreement with measured van der Waals energy of interaction across a lipid film. It appears that fluctuations at infrared frequencies and microwave frequencies are very important although these are usually ignored in preference to UV contributions. “Retardation effects” are such as to damp out high frequency fluctuation contributions; if interaction specificity is due to UV spectra, this will be revealed only at interactions across <200 angstrom (A). Dependence of van der Waals forces on material electric properties is discussed in terms of illustrative numerical calculations.     

Van der Waals locks: loop-n-lock structure of globular proteins

In a globular protein the polypeptide chain returns to itself many times, making numerous chain-to-chain contacts. The stability of these contacts is maintained primarily by van der Waals interactions. In this work we isolated and analysed van der Waals contacts that stabilise spatial structures of nine major folds. We suggest a specific way to identify the tightest contacts of prime importance for the stability of a given crystallized protein and introduce the notion of the van der Waals lock. The loops closed by the van der Waals interactions provide a basically novel view of protein globule organization: the loop-n-lock structure. This opens a new perspective in understanding protein folding as well: the consecutive looping of the polypeptide chain and the locking of the loop ends by tight van der Waals interactions.     

The Hierarchical Structure of Ecosystems: Connections to Evolution

Ecologic systems, which are involved mainly in the processing of energy and materials, are actually nested one inside another—they are simultaneously parts and wholes. This fundamental hierarchical organization is easy to detect in nature but has been undervalued by ecologists as a source of new insights about the structure and development of ecosystems and as a means of understanding the crucial connections between ecologic processes and large-scale evolutionary patterns. These ecologic systems include individual organisms bundled into local populations, populations as functional components of local communities or ecosystems, local systems making up the working parts of larger regional ecosystems, and so on, right up to the entire biosphere. Systems at any level of organization can be described and interpreted based on aspects of scale (size, duration, and “membership” in more inclusive entities), integration (all the vital connections both at a particular focal level and across levels of hierarchical organization), spatiotemporal continuity (the “life history” of each system), and boundaries (either membranes, skins, or some other kind of border criterion). Considering hierarchical organization as a general feature of ecologic systems could reinvigorate theoretical ecology, provide a realistic scaling framework for paleoecologic studies, and – most importantly – forge new and productive connections between ecology and evolutionary theory.     

Children’s Intuitive Teleology: Shifting the Focus of Evolution Education Research

Research has shown that children usually provide teleological explanations for the features of organisms and artifacts, from a very early age (3–4 years old). However, there is no consensus on whether teleological explanations are given in the same manner for non-living natural objects as well. The present study aimed to document the teleological explanations of 5- to 8-year-old children for particular features (color and shape) of organisms, artifacts and non-living natural objects. In addition, it was examined if there was any correlation between these explanations and children’s explanations for the usefulness of those features. Our results indicate a developmental shift in children’s teleological explanations, from a non-selective teleology in pre-school to a selective one in the second grade. In the latter case, children provided teleological explanations mostly for the shape of the feet of organisms and for the shape of artifacts, whereas pre-school children provided teleological explanations for non-living natural objects as well, both for the color and for the shape in all cases. Our results are not conclusive and further research is required, including a larger spectrum of students, since teleology is one of the most important conceptual obstacles in understanding evolution that persists even into adulthood. We conclude by proposing a particular research program for this purpose.     

Direct measurement of the intermolecular forces between counterion-condensed DNA double helices. Evidence for long range attractive hydration forces.

Rather than acting by modifying van der Waals or electrostatic double layer interactions or by directly bridging neighboring molecules, polyvalent ligands bound to DNA double helices appear to act by reconfiguring the water between macromolecular surfaces to create attractive long range hydration forces. We have reached this conclusion by directly measuring the repulsive forces between parallel B-form DNA double helices pushed together from the separations at which they have self organized into hexagonal arrays of parallel rods. For all of the wide variety of "condensing agents" from divalent Mn to polymeric protamines, the resulting intermolecular force varies exponentially with a decay rate of 1.4-1.5 A, exactly one-half that seen previously for hydration repulsion. Such behavior qualitatively contradicts the predictions of all electrostatic double layer and van der Waals force potentials previously suggested. It fits remarkably well with the idea, developed and tested here, that multivalent counterion adsorption reorganizes the water at discrete sites complementary to unadsorbed sites on the apposing surface. The measured strength and range of these attractive forces together with their apparent specificity suggest the presence of a previously unexpected force in molecular organization.     

Quantum microbiology

During his famous 1943 lecture series at Trinity College Dublin, the reknown physicist Erwin Schrodinger discussed the failure and challenges of interpreting life by classical physics alone and that a new approach, rooted in Quantum principles, must be involved. Quantum events are simply a level of organization below the molecular level. This includes the atomic and subatomic makeup of matter in microbial metabolism and structures, as well as the organic, genetic information code of DNA and RNA. Quantum events at this time do not elucidate, for example, how specific genetic instructions were first encoded in an organic genetic code in microbial cells capable of growth and division, and its subsequent evolution over 3.6 to 4 billion years. However, due to recent technological advances, biologists and physicists are starting to demonstrate linkages between various quantum principles like quantum tunneling, entanglement and coherence in biological processes illustrating that nature has exerted some level quantum control to optimize various processes in living organisms. In this article we explore the role of quantum events in microbial processes and endeavor to show that after nearly 67 years, Schr?dinger was prophetic and visionary in his view of quantum theory and its connection with some of the fundamental mechanisms of life.     

Binding of viral glycoprotein with trypsin and its relation to virulency. II. Comparison between bovine and Streptomyces griseus trypsins.

The two step nature of the binding reaction between trypsin and viral glycoproteins was further investigated using two types of trypsin, bovine trypsin and Streptomyces griseus trypsin. The experimental results were explained by the van der Waals energy operating in the second step, suggesting that the conformational aspects, in addition to the electrostatic nature, of the interacting peptides are decisive in this specific process.