Philosophy and History of Science
Main subjects of the books and articles listed below are the physical foundations of biology, the relation between mental and physical brain states, the evolution of general capabilities of the human brain, the historical origins of modern sciences and the scope and limits of human cognition as revealed by the history and structure of science.
Im Spiegel der Natur erkennen wir uns selbst
Wissenschaft und Menschenbild [ download as PDF-file, 0.9 MB]
(Rowohlt, Hamburg 1998)
The book on "Science and the image of man" pursues different pathways by way of which science contributes to the understanding of human beings as a species: the scope and limits of human cognition are revealed by the history and the mental structure of science in a more precise manner than by any other cultural effort. Insights into the evolution and function of the human brain elucidate the origin and the range of general human capabilities, such as language, self-representation and strategic thought. These capabilities are the products of biological evolution as well as preconditions of cultural development, which is based on traditions rather than on genetic inheritance. At the metatheoretical level, modern science reveals its own intrinsic limitations and is open to different cultural and philosophical interpretations. Human consciousness is a product of evolution of the human brain, and yet it may not be possible to decode the mind-brain relation fully by finite procedures. One of the specifically human capabilities is cognition-based empathy; it may have evolved in conjunction with strategic thought, because it facilitates the prediction of the behaviour of others, but it also motivates altruistic behaviour. Stereotyped controversies between sociologists and social biologists on human ethics appear somewhat outdated; there is a biological basis in humans not only for egoism but, to a limited extent, also for cooperativity and solidarity. Ethical demands should respect the biological conditions of the human species. They imply that cooperativeness is a real but limited resource. It requires activation, but excessive moralism is counterproductive.
Die gedachte Natur
Ursprünge moderner Wissenschaft [download as PDF-file, 1MB]
(Piper, München 1991 and Rowohlt TB, Reinbek 1998)
The explanation of nature in theoretical terms was first postulated and initiated by Ancient Greek philosophers. With the rise of monotheistic religions, however, curiosity about our transient world was widely regarded as contributing nothing to salvation. There was a decline in natural philosophy, which lasted for several centuries and was then reversed both in Islamic philosophy and in Christian theology in the Middle Ages. At this point, the "Book of Nature" was recognized as a complement to the Book of Revelation. Originally, Aristotelian philosophy played the leading part in this process, but only after Aristotelian physics was substituted by experimental mathematical mechanics did it become possible for modern science to develop. General laws of physics form the basis of the explanation of events in space and time, including life processes. However, modern science has also revealed its own limitations. The scope and limits of scientific knowledge allows for different philosophical, cultural and religious interpretations of human beings and the universe. The history of science demonstrates erratic and persistent developments, the former emphasizing the impact of specific cultural features, the latter revealing a hidden relationship between structures of human thought and the order of nature around us. The transcultural acceptance of modern science is probably based on the biologically anchored cognitive capabilities of human brains. In conclusion, the long-term retrospective view discredits extreme forms of relativism and structuralism; science appears as a construct of the human mind, and yet it is capable of generating valid explanations of nature. In the book more attention than usual is given to Heraclitus, al Kindi, Thierry of Chartres, John Donne and Schelling, and particular emphasis is placed on Nicolas de Cusa.
Cusanus - Philosophie im Vorfeld moderner Naturwissenschaft
(Koenigshausen und Neumann, Wuerzburg 2002)
The main part of this booklet is essentially the same as the chapter on Nicolas de Cusa in my book "Die gedachte Natur" (1991), which has been out of print since 2002. It is addressed mainly to those interested in the life and thoughts of one of the greatest intellectual figures of the early Renaissance. While his neo-Platonic and theological thoughts receive much attention, the same cannot be said of his remarkable contributions to the philosophy of nature. It is not claimed that science would have evolved otherwise without him; but in the thinking of one person, Cusanus united essential concepts and ideas that underlie the dynamic development of later post-Renaissance European science. He proclaimed human self-confidence: as God created the Universe in reality, man creates it in his mind. Not only mathematics, but also quantitative experiments, are essential for understanding nature. Human rationality is superior to verbal interpretations of the Bible: the universe is almost infinite, with no limits and no centre, and with a moving earth. And he insisted on what he considered to be the highest form of knowledge: the knowledge of the limits of knowledge. This reminds us of the limitations of scientific thoughts revealed by science itself, such as Heisenberg's uncertainty and Gödel's undecidability - and has far-reaching implications for the philosophy of nature and human cognition.
Dietrich von Engelhardt and Alfred Gierer (eds.):
Georg Ernst Stahl (1659-1734) in wissenschaftshistorischer Sicht
Acta Historica Leopoldina 30 (2000), ISBN 3-8047-2088-9, Wissenschaftliche Verlagsgesellschaft, Stuttgart
This book on the German chemist and physician Georg Ernst Stahl in historical perspective, documenting a symposium in Halle 1998, is on the wide scope of his thoughts and works, including the phlogiston theory of combustion which was later disproved by the discovery of oxygen, and yet contributed essential insights with respect to the reversibility of reactions, and the hidden persistence of chemical components involved; and his thoughts on the role of "anima" which are rather outdated today, and yet they introduced, as early as the turn of the 17th century, concepts relevant to modern biology and psychology such as homoeostasis, synergy, the preparation of voluntary movements, and distinctions between unconscious yet reasonable actions, and those directed by rational, conscious deliberations. While the book is in German, a short article in English placing emphasis on these aspects is the contribution by
Alfred Gierer, "Georg Ernst Stahl (1659-1734), German Physician and Chemist" in the "Encyclopedia of the Enlightenment" (A.C.Kors, ed.), vol. 4, p 124-125, Oxford University Press, New York 2003.
Die Physik, das Leben und die Seele
(Piper, München 1985, 1991) Download as PDF-File (1.3MB)
This book on "Physics, life and mind" is on the physical foundations of modern biology. The basic features of living systems, reproduction, mutation and metabolism, can be explained in terms of molecular processes involving nucleic acids as genetic material, and proteins as catalysts. The generation of structure and form in each generation results from spatiotemporal gene regulation in conjunction with the de novo formation of spatial order in which interplays of activation and inhibition play a crucial part. Brain functions can be understood in terms of information processing in neural networks. Fundamental limitations of explanations of biological phenomena on the basis of physics are expected for the relation between neural and mental states, which may not be fully decodable by finite procedures. A complete algorithmic theory of the human mind encompassing all, including self-referential, aspects appears to be impossible even in principle, not only in practice. The range and limitations of explanations of life on the basis of physical laws and processes reflect the scope and limits of science in general. In contrast to the notions in circulation in the 19th century, modern science is open at the metatheoretical level to different philosophical, cultural and religious interpretations of man and the universe.
Eriugena, al Kindi, Nikolaus von Kues - Protagonisten einer wissenschaftsfreundlichen Wende im philosophischen und theologischen Denken. With summarizing English version: Eriugena, al-Kindi, Nicholas of Cusa - Protagonists of pro-scientific change in philosophical and theological thought.
(Monography in the series Acta historica Leopoldina Nr. 29, Barth Verlag in MVH Verlage Heidelberg, 1999 / ISBN 3-8047-2087-0; Wissenschaftliche Verlagsgesellschaft, Stuttgart 2004). Download as PDF -File (3.5 MB, 61 Pages)
An abridged English version is available Download as PDF-File (17 pages):
Eriugena and al-Kindi - ninth century protagonists of pro-scientific cultural change
Ancient Greek philosophers were the first to postulate the possibility of explaining nature in theoretical terms and to initiate attempts at this. With the rise of monotheistic religions of revelation claiming supremacy over human reason and envisaging a new world to come, studies of the natural order of the transient world were widely considered undesirable. Later, in the Middle Ages, the desire for human understanding of nature in terms of reason was revived. This article is concerned with the fundamental reversal of attitudes, from "undesirable" to "desirable", that eventually led into the foundations of modern science. One of the earliest, most ingenious and most interesting personalities involved was Eriugena, a theologian at the Court of Charles the Bald in the 9th century. Though understanding what we call nature is only one of the several aspects of his philosophical work, his line of thought implies a turn into a pro-scientific direction: the natural order is to be understood in abstract terms of "primordial causes"; understanding nature is considered to be the will of God; man encompasses the whole of creation in a physical as well as a mental sense. Basically similar ideas on the reconciliation of scientific rationality and monotheistic religions of revelation were conceived, independently and nearly simultaneously, by the Arab philosopher al-Kindi in Bagdad. Eriugena was more outspoken in his claim that reason is superior to authority. This claim is implicit in the thought of Nicholas of Cusa with his emphasis on human mental creativity as the image of God's creativity; and it is the keynote of Galileo's "Letter to the Grand Duchess Christina" some 800 years later, the manifesto expressing basic attitudes of modern science.
Alfred Gierer (1988)
Biological pattern formation and Physico-Chemical Laws
In: Synergetics and Dynamic Instabilities (Caglioti, G. and Haken, H., eds), [PDF]
International school of physics Enrico Fermi, Varenna, Villa Monastero,
June 24-July 4 1986, pp.151-174. Bologna, Societa Italiana de Fisica 1988.
Physical principles underlying biological pattern formation are discussed. In particular, the combination of local self-enhancement and long-range (lateral) inhibition (Gierer and Meinhardt, 1972) accounts for de-novo pattern formation, and for striking features of developmental regulation such as induction, spacing and proportion regulation of centers of activation in tissues and cells. Part I explains physical principles of spatial organisation in biological development. Part II demonstrates in mathematical terms that and how short-range activation and long-range inhibition are conditions for the generation of spatial concentration patterns. The conditions can be expressed in terms of ranges, rates and orders of reactions. These conditions, in turn, can also be derived by analysis of dynamic instabilities by means of Fourier waves, showing the neither obvious nor trivial relation between the latter approach and the theory based primarily on autocatalysis and lateral inhibition.
Alfred Gierer (2002a)
Theoretical approaches to holistic biological features: Pattern formation, neural networks, and the brain - mind relation.
Journal of Biosciences 27 (3), 195-205 [PDF]
The topic of this article is the relation between bottom-up and top-down, reductionist and "holistic" approaches to the solution of basic biological problems. While there is no doubt that the laws of physics apply to all events in space and time, including the domains of life, understanding biology depends not only on elucidating the role of the molecules involved, but, to an increasing extent, on systems theoretical approaches in diverse fields of the life sciences. Examples discussed in this article are the generation of spatial patterns in development by the interplay of autocatalysis and lateral inhibition; the evolution of integrating capabilities of the human brain, such as cognition-based empathy; and both neurobiological and epistomological aspects of scientific theories of consciousness and the mind.
Alfred Gierer (2002b):
Holistic Biology - Back on stage? Comments on post - genomics in historical perspective.
Philosophia Naturalis 39, 25-44 Also as Preprint 162 (2001) , Max Planck Institute for the History of Science, Berlin
PDF download available: www.mpiwg-berlin.mpg.de/Preprints/P162.pdf
A strong motivation for the human genome project was to relate biological features to the structure and function of small sets of genes, and ideally to individual genes. However, it is now increasingly realized that many problems require a "systems" approach emphasizing the interplay of large numbers of genes, and the involvement of complex networks of gene regulation. New projects of "transcriptomics" and "proteomics" are being conceived along these lines: This implies a new emphasis on integrative, systems theoretical approaches. It may be called 'holistic' , if the term is used without irrational overtones, in the general sense of directing attention to integrated features of organs and organisms. In the history of biology, seemingly conflicting reductionist and holistic notions have alternated, with bottom-up as well as top-down approaches eventually contributing to the solutions to basic problems. By now, there is no doubt that biological features and phenomena are rooted in physico-chemical processes of the molecules involved; and yet, integrated systems aspects are becoming more and more relevant in developmental biology, brain and behavioural science, and sociobiology. Correspondingly, theoretical biology is expected to be increasingly involved in progress in these fields.
Alfred Gierer (1991).
Regulation and reproducibility of morphogenesis
Seminars in Developmental Biology 2 , 83-93 [PDF]
Development of biological structures is characterized by their complexity as well as their reproducibility. Complex structures may result from chains of events which are cell-autonomous, or based on contact-mediated cell interactions, such as cell proliferation, movement, inductive contacts, and cell differentiation. In sequences of such events, however, it is likely that small deviations at early stages lead to gross distortions later; reproducibility thus appears to require stabilizing and error correcting mechanisms. An effective mechanism of this type presumably is the generation of spatial concentration patterns arising by an interplay of short range activation and inhibitory effects of longer range; once established, they may function as 'morphogenetic fields' directing spatial organization in cells and tissues. Their simplest forms are monotonic gradients. On physico-chemical grounds, such fields are expected to be relatively independent of initiating conditions, and robust against distortions, and they may regulate sizes of parts in relation to the size of the whole. Processes of tissue evagination and axonal navigation are further examples of developmental mechanisms which are resistent, to an impressive extent, to temporary inhibition, deviations and distortions; for instance, misrouted axonal fibers are often capable of still approaching the appropriate target. A common feature of the different types of developmental regulation mentioned is postulated to be the approach to a temporarily stable steady state of a system. Such mechanisms appear to be required for the reliable generation of defined complex structures. Most likely, evolution has introduced them to the extent that they are of evolutionary advantage for securing reproducibility.
Alfred Gierer (1996).
Organisms-Mechanisms: Stahl, Wolff, and the case against reductionist exclusion.
Science in Context 9, 511-528
Unlike Aristotelian physics with its teleological notions, modern physics was developed exclusively in relation to the nonliving domain. This raised the question as to whether mechanics applies to organisms, and if so, to what extent. From the seventeenth century on, mechanistic ideas became prominent in biological and medical theory. Contemporary biology explains essential features of life on the basis of physical laws and processes. This does not prove, however, that the early mechanists were essentially right. In the eighteenth century, following Cartesian notions of mind-body separation and preformation theories of organismic development, they tended to exclude major biological questions rather than answering them. It was those who insisted on the organizational features of organisms, like Stahl and Wolff, who paved the way for solutions to such crucial problems as the psychological basis of human nature and behavior and the generation of form in the course of reproduction. Though they underrated the potentials of a future, extended physics for understanding biology, their case against reductionist exclusion should not be considered outdated even today.
Alfred Gierer (2000)
On Modern Science, Human Cognition and Cultural Diversity
Preprint 137, Max Planck Institute for the History of Science, Berlin
PDF download available: www.mpiwg-berlin.mpg.de/Preprints/P137.pdf
The development of modern science has depended strongly on specific features of the cultures involved; however, its results are widely and transculturally accepted and applied. The science and technology of electricity, for example, emerged as a specific product of post-Renaissance Europe, rooted in the Greek philosophical tradition that encourages explanations of nature in theoretical terms. It did not evolve in China presumably because such encouragement was missing. The transcultural acceptance of modern science and technology is postulated to be due, in part, to the common biological dispositions underlying human cognition, with generalizable capabilities of abstract, symbolic and strategic thought. These faculties of the human mind are main prerequisites for dynamic cultural development and differentiation. They appear to have evolved up to a stage of hunters and gatherers perhaps some 100 000 years ago. However, the extent of the correspondence between some constructions of the human mind and the order of nature, as revealed by science, is a late insight of the last two centuries. Unless we subscribe to extreme forms of constructivism or historical relativism, we may take the success and the formal structure of science as indications of a close, intrinsic relation between the physical and the mental, between the order of nature and the structure of human cognition. At the metatheoretical level, however, modern science is consistent with philosophical and cultural diversity.
Alfred Gierer (1997).
Goedel meets Carnap: A prototypical discourse on science and religion.
Zygon 32, 207-217 (an electronic version in PDF)
Modern science, based on the laws of physics, claims validity for all events in space and time. However, it also reveals its own limitations, such as the indeterminacy of quantum physics, the limits of decidability, and, presumably, limits of decodability of the mind-brain relationship. At the philosophical level, these intrinsic limitations allow for different interpretations of the relation between human cognition and the natural order. In particular, modern science may be logically consistent with religious as well as agnostic views of humans and the universe. These points are exemplified through the transcript of a discussion between Kurt Goedel and Rudolf Carnap that took place in 1940. Goedel, discoverer of mathematical undecidability, took a proreligious view; Carnap, one of the founders of analytical philosophy, an antireligious view. By the time of the discussion, Carnap had liberalized his ideas on theoretical concepts of science: he believed that observational terms do not suffice for an exhaustive definition of theoretical concepts. Then, responded Goedel, one should formulate a theory or metatheory that is consistent with scientific rationality, yet also encompasses theology. Carnap considered such theories unproductive. The controversy remained unresolved, but its emphasis shifted from rationality to wisdom, not only in the Goedel-Carnap discussion but also in our time.
Alfred Gierer (2000)
Ibn Khaldun on Solidarity ("Asabiyah") - Modern Science on Cooperativeness and Empathy: a Comparison.
Philosophia Naturalis 38, 91-104 [an electronic version in PDF]
Understanding cooperative human behaviour depends on insights into the biological basis of human altruism, as well as into socio-cultural development. In terms of evolutionary theory, kinship and reciprocity are well established as underlying cooperativeness. Reasons will be given suggesting an additional source, the capability of a cognition-based empathy that may have evolved as a by-product of strategic thought. An assessment of the range, the intrinsic limitations, and the conditions for activation of human cooperativeness would profit from a systems approach combining biological and socio-cultural aspects. However, this is not yet the prevailing attitude among contemporary social and biological scientists who often hold prejudiced views of each other's notions. It is therefore worth noticing that the desirable integration of aspects has already been attempted, in remarkable and encouraging ways, in the history of thought on human nature. I will exemplify this with the ideas of the fourteenth century Arab-Muslim historian Ibn Khaldun. He set out to explicate human cooperativeness - "asabiyah" - as having a biological basis in common descent, but being extendable far beyond within social systems, though in a relatively unstable and attenuated fashion. He combined psychological and material factors in a dynamical theory of the rise and decline of political rulership, and related general social phenomena to basic features of human behaviour influenced by kinship, expectation of reciprocity, and empathic emotions.
Alfred Gierer (1998).
Networks of gene regulation, neural development and the evolution of general capabilities, such as human empathy.
Z. Naturforsch. 53c, Special issue "Natural organisms, artificial organisms and their brains", 716-722
A network of gene regulation organized in a hierarchical and combinatorial manner is crucially involved in the development of the neural network, and is to be considered one of the main substrates of genetic change in its evolution. Though qualitative features may emerge by way of the accumulation of rather unspecific quantitative changes, it is reasonable to assume that at least in some cases specific combinations of regulatory parts of the genome initiated new directions of evolution, leading to novel capabilities of the brain. These notions are applied, in this paper, to the evolution of the capability of cognition-based human empathy. It is suggested that it has evolved as a secondary effect of the evolution of strategic thought. Development of strategies depends on abstract representations of one's own possible future states in one's own brain to allow assessment of their emotional desirability, but also on the representation and emotional evaluation of possible states of others, allowing anticipation of their behaviour. This is best achieved if representations of others are connected to one's own emotional centres in a manner similar to self-representations. For this reason, the evolution of the human brain is assumed to have established representations with such linkages. No group selection is involved, because the quality of strategic thought affects the fitness of the individual. A secondary effect of this linkage is that both the actual states and the future perspectives of others elicit vicarious emotions, which may contribute to the motivation of altruistic behaviour.
Alfred Gierer (2004)
Human Brain Evolution, Theories of Innovation, and Lessons from the History of Technology.
Journal of Biosciences 29(3), 235-244 [PDF]
(Also as Preprint 254, Max-Planck-Insitut für Wissenschaftsgeschichte Berlin)
Biological evolution and technological innovation, while differing in many respects, also share common features. In particular, the implementation of a new technology in the market is analogous to the spreading of a new genetic trait in a population. Technological innovation may occur either through the accumulation of quantitative changes, as in the development of the ocean clipper, or it may be initiated by a new combination of features or subsystems, as in the case of steamships. Other examples of the latter type are electric networks that combine the generation, distribution, and use of electricity, and containerized transportation that combines standardized containers, logistics, and ships. Biological evolution proceeds, phenotypically, in many small steps, but at the genetic level novel features may arise not only through the accumulation of many small, common mutational changes, but also when distinct, relatively rare genetic changes are followed by many further mutations. New evolutionary directions may be initiated by, in particular, some rare combinations of regulatory sections within the genome.
The combinatorial type of mechanism may not be a logical prerequisite for biological innovation, but it can be efficient, especially when novel features arise out of already highly developed systems. Such is the case with the evolution of general, widely applicable capabilities of the human brain. Hypothetical examples include the evolution of strategic thought, which encompasses multiple self-representations, cognition-based empathy, meta-levels of abstraction, and symbolic language. These capabilities of biologically modern man may have been initiated, perhaps some 150 000 years ago, by one or few accidental but distinct combinations of modules and subroutines of gene regulation which are involved in the generation of the neural network in the cerebral cortex. This hypothesis concurs with current insights into the molecular biology of the combinatorial and hierarchical facets of gene regulation that underlie brain development. A theory of innovation encompassing technological as well as biological development cannot per se dictate alternative explanations of biological evolution, but it may help in adding weight and directing attention to notions outside the mainstream, such as the hypothesis that few distinct genetic changes were crucial for the evolution of modern man.
Alfred Gierer (2002c)
Biologie, Menschenbild und die knappe Ressource Gemeinsinn
(BBAW - Arbeitsgruppe Gemeinwohl und Gemeinsinn, Tagung 11.-13. Juni 1999, Forschungsbericht Bd. IV, H. Münkler und H. Bluhm, Hsg., S. 19-36. Akademieverlag Berlin 2002).
Preprint available for download
Unsere Kulturfähigkeit ist ein Ergebnis der biologischen Evolution der Spezies "Mensch"; die einzelne Kultur selbst jedoch ist ein Produkt gesellschaftlicher Entwicklungen, Differenzierungen und Traditionen. Der Kulturvergleich zeigt uns erhebliche Spielräume für Ausprägungen von Gemeinsinn. Da dessen Aktivierung wesentlich zur Lebensqualität einer Gesellschaft beiträgt, sind Versuche einer realistischen EinschÃ¤tzung kultureller GestaltungsspielrÃ¤ume in dieser Hinsicht sinnvoll. Sie sind nicht zuletzt durch die biologischen Grund- und Randbedingungen der Spezies Mensch gegeben und begrenzt, zumal hinsichtlich von Anlagen zu altruistischem und kooperativem Verhalten. Während bis vor kurzem Soziobiologen und Sozialwissenschaftler oft wenig Neigung zu gegenseitigem Verständnis zeigten, zumal manche Biologen relativ extreme Theorien über genetisch angelegte egoistische Verhaltensanlagen vertraten, verstehen sich neuere, durch die Spieltheorie beeinflusste und sehr allgemeine psychische Disposition betonende Linien soziobiologischen Denkens dazu, auch ausgesprochen freundliche Eigenschaften unserer Spezies zu erklären und zu begründen. Sie kommen sozialwissenschaftlichen Bestrebungen entgegen, zum Beispiel in Zusammenhang mit Theorien begrenzt rationalen Verhaltens, in denen die Fairness eine wesentliche Rolle spielt. Besondere Aufmerksamkeit verdienen in diesem Zusammenhang die biologisch angelegte Fähigkeit zu kognitionsgestätzter Empathie sowie die fragile Anlage "Vertrauensbereitschaft", von denen die Effizienz und das Wohlbefinden in einer Gesellschaft wesentlich abhängen. Insgesamt kann eine - keineswegs unkritische - Beachtung evolutionsbiologischer Aspekte menschlicher Verhaltensdispositionen zu einer realistischen Einschäätzung der knappen Ressource "Gemeinsinn" beitragen. Sie ist in Grenzen durchaus ein auch in der Natur des Menschen angelegtes Potential. Dies ist jedoch - unter Beachtung eben dieser Grenzen - behutsam zu aktivieren. Moralische Ã?berforderungen, welche die natürlichen Anlagen des Menschen missachten, sind kontraproduktiv.
Unter dem gleichen Titel wie der vorstehende Artikel erscheint die Monographie:
Alfred Gierer (2005), Biologie, Menschenbild und die knappe Ressource Gemeinsinn.
Königshausen und Neumann, Würzburg.
Das Buch geht ausführlicher auf die biologischen Voraussetzungen höherer menschlicher Gehirnähigkeiten und sozialen Verhaltens ein und basiert wesentlich auf vier Kapiteln des (vergriffenen) Buches - siehe oben - "Im Spiegel der Natur erkennen wir uns selbst - Wissenschaft und Menschenbild"..
Alfred Gierer (1983).
Relation between Neurophysiological and Mental States: Possible Limits of Decodability [PDF].
Naturwissenschaften 70, 282-287
Validity of physical laws for any aspect of brain activity and strict correlation of mental to physical states of the brain do not imply, with logical necessity, that a complete algorithmic theory of the mind-body relation is possible. A limit of decodability may be imposed by the finite number of possible analytical operations which is rooted in the finiteness of the world. It is considered as a fundamental intrinsic limitation of the scientific approach comparable to quantum indeterminacy and the theorems of logical undecidability. An analysis of these limits, applied to dispositions of future behaviour, suggests that limits of decodability of the psycho-physic relation may actually exist with respect to brain states with self-referential aspects, as they are involved in mental processes. Among possible empirical approaches to such aspects, studies on a class of "metatheoretical" jokes may be helpful which suggest that our brain is capable of immediate perception of hidden inconsistencies resulting from self-applications of concepts and logical operations. Limits for an algorithmic theory of the mind-body problem suggested by this study are formally similar to other intrinsic limits of the scientific method such as quantum indeterminacy and mathematical undecidability: they are related to self-referential operations. Hard sciences, despite their reliability, universality and objectivity, depend on metatheoretical presuppositions which allow for multiple philosophical interpretations.
Alfred Gierer (2008)
Brain, mind, and limitations of a scientific theory of human consciousness
BioEssays 30, 499-505 [PDF]
In biological terms, human consciousness appears as a feature associated with the functioning of the human brain. The corresponding activities of the neural network occur strictly in accord with physical laws; however, this fact does not necessarily imply that there can be a comprehensive scientific theory of consciousness, despite all the progress in neurobiology, neuropsychology and neurocomputation. Predictions of the extent to which such a theory may become possible vary widely in the scientific community. There are basic reasons - not only practical but also epistemological - why the brain-mind relation may never be fully “decodable” by general finite procedures. In particular self-referential features of consciousness, such as self-representations involved in strategic thought and dispositions, may not be resolvable in all their essential aspects by brain analysis. Assuming that such limitations exist, objective analysis by the methods of natural science cannot, in principle, fully encompass subjective, mental experience.
Alfred Gierer (2008)
Bewusstsein – Reichweite und Grenzen naturwissenschaftlicher Erklärung.
Beitrag zur Arbeitsgruppe „Humanprojekt – Die Stellung des Menschen in der Natur“ der Berlin-Brandenburgischen Akademie der Wissenschaften. In: Funktionen des Bewusstseins, Humanprojekt/Interdisziplinäre Anthropologie 2 (D. Ganten, V. Gerhardt, J. Nida-Rümelin, Hg.), de Gruyter, Berlin 2008. [preprint als PDF]
Nach einem kurzen Resümee über entscheidungstheoretisch begründete Grenzen einer rein naturwissenschaftlichen Theorie menschlichen Bewusstseins werden Implikationen für unser Menschenbild erörtert. Was die Willensfreiheit angeht, so sprechen starke erkenntnistheoretische Gründe dagegen, dass der Wille Anderer durch Analyse von Außen vollständig erschließbar sein könnte; was aber für niemanden determiniert ist, ist nicht determiniert. Für die Evolution mentaler Fähigkeiten, die den biologisch modernen Menschentyp charakterisieren, könnten auch einzelne, eher seltene Neukombinationen von Abschnitten im Genom eine wesentliche Rolle gespielt haben. Die entwickelten Fähigkeiten und Eigenschaften führten dann weit über den Anlass ihrer Entstehung hinaus. Hinsichtlich der menschlichen Erkenntnisfähigkeit ist die grundsätzliche philosophische Frage, ob und wieweit es eine Ordnung der Welt lediglich als Konstrukte unserer Gehirne, oder aber auch vor und ohne uns gibt, rein neurobiologisch sicher nicht zu entscheiden. Dies betrifft zum Beispiel das Grundverständnis der Mathematik, aber auch das von Religion. Naturwissenschaften insgesamt und ihre wissenschaftlich begründeten Grenzen sind mit verschiedenen, natürlich nicht mit allen philosophischen, kulturellen und religiösen Deutungen vereinbar.
Alfred Gierer (2012)
The Hydra model – a model for what?
Special Issue on “The Hydra model system”. Int. J. Dev. Biol., 56, 437-445 [PDF]
The introductory personal remarks refer to my motivations for choosing research projects, and for moving from physics to molecular biology and then to development, with Hydra as model system. Historically, Trembley’s discovery of Hydra regeneration in 1744 was the beginning of developmental biology as we understand it, with passionate debates about preformation versus de-novo generation, mechanisms versus organisms. In fact, seemingly conflicting bottom-up and top-down concepts are both required in combination to understand development. In modern terms this means analysing the molecules involved, as well as searching for physical principles underlying development within systems of molecules, cells and tissues. During the last decade molecular biology has provided surprising and impressive evidence that the same types of molecules and molecular systems are involved in pattern formation in a wide range of organisms, including coelenterates like Hydra, and thus appear to have been “invented” early in evolution. Likewise, certain system’s features, especially those of developmental regulation, are found in many different organisms. This includes the generation of spatial structures by the interplay of self-enhancing activation and “lateral” inhibitory effects of wider range, which is a main topic of my essay. Hydra regeneration is a particularly clear model for the formation of defined patterns within initially near-uniform tissues. In conclusion, the essay emphasizes the analysis of development in terms of physical laws, including the application of mathematics, and insists that Hydra was, and will continue to be, a rewarding model for understanding general features of embryogenesis and regeneration.