The ultimate source of explanation in biology is the principle of natural selection. Natural selection means differential reproduction of genes and gene combinations. It is a mechanistic process which accounts for the existence in living organisms of end-directed structures and processes. It is argued that teleological explanations in biology are not only acceptable but indeed indispensable. There are at least three categories of biological phenomena where teleological explanations are appropriate.
This collection of specially commissioned essays puts top scholars head to head to debate the central issues in the lively and fast growing field of philosophy ...
The question whether ethical behavior is biologically determined may refer either to thecapacity for ethics (e.i., the proclivity to judge human actions as either right or wrong), or to the moralnorms accepted by human beings for guiding their actions. My theses are: (1) that the capacity for ethics is a necessary attribute of human nature; and (2) that moral norms are products of cultural evolution, not of biological evolution.Humans exhibits ethical behavior by nature because their biological makeup determines the presence (...) of the three necessary, and jointly sufficient, conditions for ethical behavior: (i) the ability to anticipate the consequences of one's own actions; (ii) the ability to make value judgements; and (iii) the ability to choose between alternative courses of action. Ethical behavior came about in evolution not because it is adaptive in itself, but as a necessary consequece of man's eminent intellectual abilities, which are an attribute directly promoted by natural selection. (shrink)
Presenting an ardent defence of Charles Darwin's theory of evolution, this book offers a clear and comprehensive exposition of Darwin's thinking. Michael Ruse brings the story up to date, examining the origins of life, the fossil record, and the mechanism of natural selection. Rival theories are explored, from punctuated equilibrium to human evolution . The philosophical and religious implications of Darwinism are discussed, including a discussion of Creationism and its modern day offshoot, Intelligent Design Theory. Ruse draws upon the most (...) recent discoveries, writing with a minimum of jargon in order to appeal to all readers, from professional biologists to those concerned that Darwinism is a naturalistic religion that is forced on school children despite their own Christian convictions. Openly revealing his own beliefs, Ruse presents readers with all the information and critical tools they need to make an informed decision on evolutionary theory. (shrink)
We explore the distinctive characteristics of Mexico's society, politics and history that impacted the establishment of genetics in Mexico, as a new disciplinary field that began in the early 20th century and was consolidated and institutionalized in the second half. We identify about three stages in the institutionalization of genetics in Mexico. The first stage can be characterized by Edmundo Taboada, who was the leader of a research program initiated during the Cárdenas government (1934-1940), which was primarily directed towards improving (...) the condition of small Mexican farmers. Taboada is the first Mexican post-graduate investigator in phytotechnology and phytopathology, trained at Cornell University and the University of Minnesota, in 1932 and 1933, respectively. He was the first investigator to teach plant genetics at the National School of Agriculture and wrote the first textbook of general genetics, Genetics Notes, in 1938. Taboada's most important single genetics contribution was the production of "stabilized" corn varieties. The extensive exile of Spanish intellectuals to Mexico, after the end of Spain's Civil War (1936-1939), had a major influence in Mexican science and characterizes the second stage. The three main personalities contributing to Mexican genetics are Federico Bonet de Marco and Bibiano Fernández Osorio Tafall, at the National School of Biological Sciences, and José Luis de la Loma y Oteyza, at the Chapingo Agriculture School. The main contribution of the Spanish exiles to the introduction of genetics in Mexico concerned teaching. They introduced in several universities genetics as a distinctive discipline within the biology curriculum and wrote genetics text books and manuals. The third stage is identified with Alfonso León de Garay, who founded the Genetics and Radiobiology Program in 1960 within the National Commission of Nuclear Energy, which had been founded in 1956. The Genetics and Radiobiology Program rapidly became a disciplinary program, for it embraced research, teaching, and training of academics and technicians. The Mexican Genetics Society, created by de Garay in 1966, and the development of strains and cultures for genetics research were important activities. One of de Garay's key requirements was the compulsory training of the Program's scientists for at least one or two years in the best universities of the United States and Europe. De Garay's role in the development of Mexican genetics was fundamental. His broad vision encompassed the practice of genetics in all its manifestations. (shrink)
Human Evolution provides a comprehensive overview of hominid evolution, synthesising data and approaches from fields as diverse as physical anthropology, evolutionary biology, molecular biology, genetics, archaeology, psychology and philosophy. The book starts with chapters on evolution, population genetics, systematics, and the methods for constructing evolutionary trees. These are followed by a comprehensive review of the fossil history of human evolution since our divergence from the apes. Subsequent chapters cover more recent data, both fossil and molecular, relating to the evolution of (...) modern humans. A final section describes the evolution of culture, language, art, and morality.The authors are leading experts in two complementary fields of scholarship, physical anthropology and molecular evolution. Throughout the book they successfully integrate their expertise in evolutionary theory, phylogenetics, genomics, cultural evolution, language, aesthetics and morality to produce a cutting edge textbook, copiously illustrated and with an extensive and up-to-date bibliography. It will be suitable for both senior undergraduate and graduate level students taking courses on human evolution within departments of biology, anthropology, psychology and philosophy. The book will also appeal to a more general audience seeking a readable, up-to-date and inclusive treatment of human origins and evolution. (shrink)
Knives, birds' wings, and mountain slopes are used for certain purposes: cutting, flying, and climbing. A bird's wings have in common with knives that they have been 'designed' for the purpose they serve, which purpose accounts for their existence, whereas mountain slopes have come about by geological processes independently of their uses for climbing. A bird's wings differ from a knife in that they have not been designed or produced by any conscious agent; rather, the wings, like the slopes, are (...) outcomes of natural processes without any intentional causation. Evolutionary biologists use teleological language and teleological explanations. I propose that this use is appropriate, because teleological explanations are hypotheses that can be subject to empirical testing. The distinctiveness of teleological hypotheses is that they account for the existence of a feature in terms of the function it serves; for example, wings have evolved and persist because flying is beneficial to birds by increasing their chances of surviving and reproducing. Features of organisms that are explained with teleological hypotheses include structures, such as wings; processes, such as development from egg to adult; and behaviours, such as nest building. A proximate explanation of these features is the function they serve; an ultimate explanation that they all share is their contribution to the reproductive fitness of the organisms. I distinguish several kinds of teleological explanations, such as natural and artificial, as well as bounded and unbounded, some of which but not others apply to biological explanations. (shrink)
William Paley ( Natural Theology , 1802) developed the argument-from-design. The complex structure of the human eye evinces that it was designed by an intelligent Creator. The argument is based on the irreducible complexity ("relation") of multiple interacting parts, all necessary for function. Paley adduces a wealth of biological examples leading to the same conclusion; his knowledge of the biology of his time was profound and extensive. Charles Darwin’s Origin of Species is an extended argument demonstrating that the "design" of (...) organisms can be explained by natural selection. Moreover, the dysfunctions, defects, waste, and cruelty that prevail in the living world are incompatible with a benevolent and omnipotent Creator. They come about by a process that incorporates chance and necessity, mutation and natural selection. In addition to science, there are other ways of knowing, such as art, literature, philosophy, and religion. Matters of value, meaning, and purpose transcend science. (shrink)
The theory of punctuated equilibrium has been proposed as a challenge to the modern synthesis of evolutionary theory. Two important issues are raised. The first is scientific: whether morphological change as observed in the paleontological record is essentially always associated with speciation events. This paper argues that there is at present no empirical support for this claim: the alleged evidence is based on a definitional fallacy. The second issue is epistemological: whether macroevolution is an autonomous field of study, independent from (...) microevolutionary knowledge. It is herein argued that macroevolution and microevolution are not decoupled in two senses: identity at the level of events and compatibility of theories. But macroevolution is autonomous in the epistemologically important sense: macroevolutionary theories are not reducible to microevolutionary principles. It is finally pointed out that the discipline of macroevolution is notoriously lacking in theoretical constructs of great import and generality. (shrink)
La humanidad no solo ha evolucionado, sino que continúa evolucionando. ¿Hacia dónde va la evolución humana? La evolución biológica está dirigida por la selección natural, que no es un proceso benevolente que guíe a las especies hacia un éxito seguro. El resultado final puede ser la extinción. Los avances en genética, biología molecular y biomedicina han hecho posible manipular, rápida y efectivamente, la constitución genética de la humanidad. La terapia genética puede ser somática, o germinal. No hay intervenciones de terapia (...) germinal que estén siendo consideradas actualmente por científicos, médicos o compañías farmacéuticas. La clonación de humanos puede también referirse a clonación terapéutica o de individuos. Se han avanzado propuestas sugiriendo clonar individuos de gran capacidad intelectual o artística, o de virtud eminente. Tales propuestas utópicas son sumamente desafortunadas. No es posible clonar un individuo humano, aun si se clona su genoma. De genomas idénticos, desarrollados en contextos diferentes, familiares, sociales y culturales, pueden resultar individuos totalmente diferentes. Además, entran en juego consideraciones éticas, sociales y religiosas cuando se examina si una persona puede o debe ser clonada. (shrink)
This paper sets forth a familiar theme, that science essentially consists of two interdependent episodes, one imaginative, the other critical. Hypotheses and other imaginative conjectures are the initial stage of scientific inquiry because they provide the incentive to seek the truth and a clue as to where to find it. But scientific conjectures must be subject to critical examination and empirical testing. There is a dialogue between the two episodes; observations made to test a hypothesis are the inspiration for new (...) conjectures. Inductive generalizations may also inspire hypotheses, but cannot validate them. A hypothesis is empirically tested by ascertaining whether or not predictions about the world of experience deduced from the hypothesis agree with what is actually observed. This has been appropriately considered the 'criterion of demarcation' that distinguishes science from other knowledge. But scientific hypotheses must satisfy other tests as well, e.g., whether they have explanatory value and further understanding. I briefly explore such issues as verifiability and falsifiability, empirical content and truthfulness, contingency and certainty, fact and theory, error and fraud. Science like any human activity is subject to error and to the foibles and other failings of human beings. But severe attempts of empirical falsification and other trials yield knowledge that stands the test of time and provides a foothold for further knowledge. Moreover, scientists have developed social mechanisms, such as peer review and publication, to evaluate their work. Because the research of scientists depends on the validity of previous knowledge, it is of great consequence that they discern valid from invalid knowledge and thus scientists are inclined to transcend ideology, nationality, friendship, monetary interest and other prejudices when the mettle of scientific knowledge is at stake. I use historical examples to illustrate some relevant aspects of scientific practice: its success (Mendel), misrepresentation (Darwin), ideological abuse (Lysenko), arrogant violation of the requirement of testing (Koch), theory replacement (Priestly and Lavoisier, Newton and Einstein), and the indispensability of context (Oswald Avery and Alfred Wegener). (shrink)
Copernicus, Galileo, Newton and other physical scientists ushered in a conception of the universe as matter in motion governed by natural laws. Their discoveries brought about a fundamental revolution, namely a commitment to the postulate that the universe obeys immanent laws that can account for natural phenomena. The workings of the universe were brought into the realm of science: explanation through natural laws. Darwin completed the Copernican revolution by extending it to the living world. Darwin demonstrated the evolution of organisms. (...) More important yet is that he discovered natural selection, the process that explains the ‘design’ of organisms. The adaptations and diversity of organisms, the origin of novel and complex species, even the origin of mankind, could now be explained by an orderly process of change governed by natural laws. The origin of species and the exquisite features of organisms had previously been explained as special creations of an omniscient God. Darwin brought them into the domain of science. (shrink)
Erect posture and large brain are two of the most significant anatomical traits that distinguish us from nonhuman primates. But humans are also different from chimpanzees and other animals, and no less importantly, in their behavior, both as individuals and socially. Distinctive human behavioral attributes include tool-making and technology; abstract thinking, categorizing, and reasoning; symbolic (creative) language; self-awareness and death-awareness; science, literature, and art; legal codes, ethics and religion; complex social organization and political institutions. These traits may all be said (...) to be components of human culture, a distinctively human mode of adaptation to the environment that is far more versatile and successful than the biological mode. Cultural adaptation is more effective than biological adaptation because its innovations are directed, rather than random mutations; because it can be transmitted "horizontally", rather than only "vertically", to descendants; and because cultural heredity is Lamarckian, rather than Mendelian, so that acquired characteristics can be inherited. I explore ethics as a distinctive human trait. The question whether ethical behavior is biologically determined may refer either to the capacity for ethics (i.e., the proclivity to judge human actions as either right or wrong), or to the moral norms accepted by human beings for guiding their actions. I will propose: (1) that the capacity for ethics is a necessary attribute of human nature; and (2) that moral norms are products of cultural evolution, not of biological evolution. (shrink)
