“Theory” in Theory and Practice

A central obstacle to accepting evolution, both among students and the general public, is the idea that evolution is “just a theory,” where “theory” is understood in a pejorative sense as something conjectural or speculative. Although scientists and textbooks constantly explain that the scientific use of “theory” is quite different, the pejorative use continues to cause confusion, in part because of its deep roots in a popular, Baconian, understanding of science. A constructivist approach, whereby students are helped to examine the adequacy of their preconceptions about “theory” for themselves and to revise or replace them appropriately, is recommended.     

The Positional Quality of Life and Death: A Theory of Human–Animal Relations in Animism

ABSTRACT

This article examines human–animal relations in animism. Ethnographies of indigenous peoples in the Americas, Asia, and Africa are compared in order to provide a basic sketch of the remarkable consistency of animism across the world. A central feature that recurs time and again is the positional quality of life and death. That is, life and death are not conceived of as inherent properties but as changeable positions. This is why indigenous hunters, shamans, and diviners temporarily “die” when they participate in the specific rites or cults associated with their respective endeavors. Such metamorphoses of the living into the dead are crucial to understand how hunters engage with their prey, shamans mobilize their animal-helpers, and honey collectors approach their bees. At the same time, these different activities involve the transformation of humans into animals. Chachi bird stalkers and Uduk antelope hunters identify themselves with their quarry, Navajo medicine men and Ainu shamans shape-change into their animallike adversaries, while Batek mourners may adopt a tiger-form. At first sight, such simultaneous metamorphoses (from the living into the dead and from humans into animals) may seem contradictory. Yet, this apparent inconsistency disappears if one realizes that the modern notion of wildlife cannot be applied to animism. I show that the monkeys, deer, whales, tigers, and elephants that indigenous hunters and shamans deal with must be understood as “wild-dead” rather than as wildlife. These various animals are palpable representatives of an expanded realm of death which—I suggest—is characteristic of all forms of animism. In this context, being animate is not sufficient to be considered “alive.”     

Theory and practice of a posteriori “Wiener” filtering of average evoked potentials

In this study a theoretical and practical analysis of the technique of a posteriori Wiener filtering of averaged evoked potentials is presented. It is shown that spectral smoothing plays a central role in obtaining a reliable estimate. Attention is paid to some practical problems that arise when the method is applied in discrete time. In an illustrative case study results are compared to theoretical Wiener filtering, while the influence of slow amplitude modulation has also been investigated. Some of the conflicting results regarding the method that have been reported in several recent papers are discussed. It is concluded, that when the method is applied with prudence, it may lead to an improved estimation of those evoked potentials that can be assumed to be approximately stationary. If the latter assumption is not valid, application of a time-varying filter technique is recommended instead.     

Edward Hitchcock’s Pre-Darwinian (1840) “Tree of Life”

The “tree of life” iconography, representing the history of life, dates from at least the latter half of the 18th century, but evolution as the mechanism providing this bifurcating history of life did not appear until the early 19th century. There was also a shift from the straight line, scala naturae view of change in nature to a more bifurcating or tree-like view. Throughout the 19th century authors presented tree-like diagrams, some regarding the Deity as the mechanism of change while others argued for evolution. Straight-line or anagenetic evolution and bifurcating or cladogenetic evolution are known in biology today, but are often misrepresented in popular culture, especially with anagenesis being confounded with scala naturae. Although well known in the mid 19th century, the geologist Edward Hitchcock has been forgotten as an early, if not the first author to publish a paleontologically based “tree of life” beginning in 1840 in the first edition of his popular general geology text Elementary Geology. At least 31 editions were published and those between 1840 and 1859 had this “paleontological chart” showing two trees, one for fossil and living plants and another for animals set within a context of geological time. Although the chart did not vary in later editions, the text explaining the chart did change to reflect newer ideas in paleontology and geology. Whereas Lamarck, Chambers, Bronn, Darwin, and Haeckel saw some form of transmutation as the mechanism that created their “trees of life,” Hitchcock, like his contemporaries Agassiz and Miller, who also produced “trees of life,” saw a deity as the agent of change. Through each edition of his book Hitchcock denounced the newer transmutationist hypotheses of Lamarck, then Chambers, and finally Darwin in an 1860 edition that no longer presented his tree-like “paleontological chart.”     

The date palm—“Tree of Life”in the subtropical deserts

Dates, staple food in the valleys of the Tigris, Euphrates and Nile rivers since the dawn of history, have been established on nearly 6,000 acres in southern California and Arizona.     

The Impact of Lamarck’s Theory of Evolution Before Darwin’s Theory

This paper analyzes the impact that Lamarckian evolutionary theory had in the scientific community during the period between the advent of Zoological Philosophy and the publication Origin of Species. During these 50 years Lamarck’s model was a well known theory and it was discussed by the scientific community as a hypothesis to explain the changing nature of the fossil record throughout the history of Earth. Lamarck’s transmutation theory established the foundation of an evolutionary model introducing a new way to research in nature. Darwin’s selectionist theory was proposed in 1859 to explain the origin of species within this epistemological process. In this context, Charles Lyell’s Principles of Geology and Auguste Comte’s Cours de Philosophie Positive appear as two major works for the dissemination of Lamarck’s evolutionary ideology after the death of the French naturalist in 1829.     

“It's a Wonderful Life”: signaling generosity among the Ache of Paraguay

Intensive food sharing among foragers and horticulturists is commonly explained as a means of reducing the risk of daily shortfalls, ensuring adequate daily consumption for all group members who actively pool resources. Consistently high food producers who give more than they receive, however, gain the least risk-reduction benefit from this daily pooling because they are the least likely to go without food on any given day. Why then do some high producers consistently share food, and why do some average producers share proportionally more food than others? We propose that although these individuals may not receive the same amounts they give (i.e., strict Tit-for-Tat), one explanation for their generosity is that they receive additional food during hard times. These include brief episodes of sickness, disease, injury, or accidents—fairly common events in traditional societies that can render individuals incapable of producing food, thereby having long-term effects on morbidity and fecundity and ultimately on lifetime reproductive success. Data collected among the Ache, a group of South American forager-horticulturists, indicate that those who shared and produced more than average (signaling cooperative intent and/or ability to produce) were rewarded with more food from more people when injured or sick than those who shared and produced below average. These results, framed within the context of tradeoffs between short-term and long-term fitness, may provide insight into motivations behind costly expenditures for establishing and reinforcing status and reputation.     

Yale Peabody Museum of Natural History’s “Travels in the Great Tree of Life”

The Yale Peabody Museum of Natural History developed a 1,000-square-foot exhibition to help the general public understand the concept of phylogenetic relationships and their depiction on scientific Trees, or cladograms. In addition, exhibition planners hoped visitors would understand that research on the Tree of Life is a massive, complex undertaking requiring powerful computers and that Tree research has many potential practical applications. Museum exhibits designed to convey scientific information must use “stealth” to accomplish their cognitive goals: Unlike students in formal science education classes, visitors are not obliged to learn—they do not learn because they must pass a final examination. Informal educators must engage visitors’ interest so that they willingly take in new information and perhaps even learn new skills, change attitudes, and behaviors. “Travels in the Great Tree of Life” succeeded in engaging visitors who came away with awareness and understanding of scientific Trees, the immensity of the construct, and to a lesser extent, potential practical applications.     

Levels or Domains of Life?

In the case of living beings – the very concept of “level” of organization becomes obscure: it suggests a value-based assessment, assigning notions like “lower” and “higher” with rather vague criteria for constructing the ladder of perfection, complexity, importance, etc. We prefer therefore the term “domain”, entities ranking equal. Domains may represent natural entities as well as purely human constructs developed in order to gain understanding of some facets of living things; living, evolved beings (e.g. viviparous animals, eukaryotic cells, etc.) as well as those abstract constructs, such as genotype and ‘niche’ which have been developed in the search for better understanding of such living things. Delimitation of such domains is sometimes a question of the dexterity of the researcher, and sometimes draws from the tradition in a given field. Such domains are not completely (canonically) translatable to each other. Rather, they interact by a process that we call here reciprocal formation. Life (including the biosphere and human cultures which are emergent within the frame of the biosphere) is unique among multi-domain systems. In contrast to purely physical systems, life is a semiotic system driven by the historical experience of lineages, interpreted and re-interpreted by the incessant turnover of both individuals and their communities. This paper provides cases of domain interrelations, and addresses two questions: (1) How do new qualities of inter-domain interaction emerge historically? (2) How do new domains (ways of understanding the world) emerge in evolution. Two approaches, physical and biosemiotic, are discussed as we seek to get a better understanding of the overarching tasks.     

What is Life? Defining Life in the Context of Emergent Complexity

Erwin Schrödinger defined life not only as a “self-reproducing” aperiodic crystal of DNA coding for proteins but within the context of living entities increasing their order by dissipating matter/energy gradients to maintain themselves away from equilibirium. Since then most definitions of life have focused on the former. But living cells do more than replicate their DNA. Cells also have membrane barriers across which metabolites must move, via which energy transduction as well as information processing occurs, and within which metabolic transformation occurs. An approach of complex systems dynamics, including nonequilibrium thermodynamics, may provide a more robust approach for defining life than a “naked replicator” at the origin of life. The crucial issue becomes the process of emergence of life from pre-biotic chemistry, concomitant with the emergence of function, information, and semiosis. Living entities can be viewed as bounded, informed autocatalytic cycles feeding off matter/energy gradients, exhibiting agency, capable of growth, reproduction, and evolution. Understanding how life might have emerged should sharpen our definition of what life is.     

A Note Against the Use of “Belonging To” Properties in Multilevel Selection Theory

Acta Biotheoretica - In this short paper, I argue against what I call the “belonging to” interpretation of group selection in scenarios in which a group’s fitness is defined as...     

What Is the Tree of Life?

A universal Tree of Life (TOL) has long been a goal of molecular phylogeneticists, but reticulation at the level of genes and possibly at the levels of cells and species renders any simple interpretation of such a TOL, especially as applied to prokaryotes, problematic.One of the several ways in which microbiology puts the neo-Darwinian synthesis in jeopardy is by the threatening to “uproot the Tree of Life (TOL)” [1]. Lateral gene transfer (LGT) is much more frequent than most biologists would have imagined up until about 20 years ago, so phylogenetic trees based on sequences of different prokaryotic genes are often different. How to tease out from such conflicting data something that might correspond to a single, universal Tree of Life becomes problematic. Moreover, since many important evolutionary transitions involve lineage fusions at one level or another, the aptness of a tree (a pattern of successive bifurcations) as a summary of life’s history is uncertain [2–4].