In my response to the paper by Jagers op Akkerhuis, I object against giving definitions of life, since they bias anything that follows. As we don’t know how life originated, authors characterise life using criteria derived from present-day properties, thus emphasising widely different ones, which gives bias to their further analysis. This makes their results dependent on their initial suppositions, which introduces circularity in their reasoning.

During the last decades the question of defining life has gained increased interest but, at the same time, the difficulty in reaching consensus on a possible answer has led many to skeptical positions. This, in turn, has raised a wider debate about why defining life is so hard and controversial. Such a debate introduces additional aspects to be considered, like the role and nature of a definition of life itself. In this paper, we will focus on those (...) aspects, arguing that progress can be made if we conceive definitions of life as open heuristic tools that contribute to develop specific research strategies in the biological sciences and, more generally, to increase our understanding of life’s complexity. In contrast with pragmatic or operationalist approaches, we will defend that definitions of life comprise a set of ontological assumptions, together with an inherent unifying vocation, so they should be subject to comparison and critical assessment, closely related to the success or failure of the corresponding research programs, but also to the success or failure in establishing well-grounded interconnections among the latter. We consider that the search for a more coherent, integrated and generalized theory of biology cannot be pursued without keeping an empirical standpoint, and the exercise of defining life should not be taken as an obstacle but as a valuable instrument to achieve that goal. (shrink)

The concept of “life” certainly is of some use to distinguish birds and beavers from water and stones. This pragmatic usefulness has led to its construal as a categorical predicate that can sift out living entities from non-living ones depending on their possessing specific properties—reproduction, metabolism, evolvability etc. In this paper, we argue against this binary construal of life. Using text-mining methods across over 30,000 scientific articles, we defend instead a degrees-of-life view and show how these methods (...) can contribute to experimental philosophy of science and concept explication. We apply topic-modeling algorithms to identify which specific properties are attributed to a target set of entities (bacteria, archaea, viruses, prions, plasmids, phages and the molecule of adenine). Eight major clusters of properties were identified together with their relative relevance for each target entity (two that relate to metabolism and catalysis, one to genetics, one to evolvability, one to structure, and—rather unexpectedly—three that concern interactions with the environment broadly construed). While aligning with intuitions—for instance about viruses being less alive than bacteria—these quantitative results also reveal differential degrees of performance that have so far remained elusive or overlooked. Taken together, these analyses provide a conceptual “lifeness space” that makes it possible to move away from a categorical construal of life by empirically assessing the relative lifeness of more-or-less alive entities. (shrink)

There have through history been many attempts to define 'life' but there is no generally accepted definition of 'life' at this date. As a result, some have come to believe that defining 'life' is not a fruitful endeavour. This seems to be a minority view, however, since the quest to find or create a definition of 'life' is as active as ever.

The definition of life is a very important issue in the philosophy of biology, but this issue has unfortunately been neglected by the mainstream philosopher of biology for many years. In this paper, the difficulties with and the reasons for defining life are illustrated, the characteristics of life on Earth are explored, ways of defining life are examined, the main definitions of life are explained and evaluated, and finally, a new information definition of (...) class='Hi'>life is proposed. (shrink)

There are about 100 different contradictory definitions of life. The definition of life based on symbiosis that is presented here differs fundamentally from them; it gives life a value. So this definition offers a basis for ethical and legal action e.g. in organ transplants. It is based on principles and is not an ad hoc model: Significant processes for life are basis for a theoretical concept. Quality criteria for definitions are employed to control the (...) concept. There is a graduation, not a clear division, between inanimate and animate. The graduation is based on the amount of symbiosis to be found. Life is based on symbiosis. The ideas of “ethics” and “reality” are considered in the context of this definition. (shrink)

The attempt to define life has gained new momentum in the wake of novel fields such as synthetic biology, astrobiology, and artificial life. In a series of articles, Cleland, Chyba, and Machery claim that definitions of life seek to provide necessary and sufficient conditions for applying the concept of life—something that such definitions cannot, and should not do. We argue that this criticism is largely unwarranted. Cleland, Chyba, and Machery approach definitions of (...) class='Hi'>life as classifying devices, thereby neglecting their other epistemic roles. We identify within the discussions of the nature and origin of life three other types of definitions: theoretical, transdisciplinary, and diagnostic definitions. The primary aim of these definitions is not to distinguish life from nonlife, although they can also be used for classificatory purposes. We focus on the definitions of life within the budding field of astrobiology, paying particular attention to transdisciplinary definitions, and diagnostic definitions in the search for biosignatures from other planets. (shrink)

Schrödinger's definition of life needs a slight modification to absorb the criticism of it. It is the comparison of the entropy level of a system before and after a process which makes one view it as living: we consider the stability of the deviation from the probable a sign of life. This explains why we do not hesitate to consider as remnants of living systems skeletons and fossils anywhere and physical culture on any archeological site.

The comments focus on a presumed circular reasoning in the operator hierarchy and the necessity of understanding life’s origin for defining life. Below it is shown that its layered structure prevents the operator hierarchy from circular definitions. It is argued that the origin of life is an insufficient basis for a definition of life that includes multicellular and neural network organisms.

Despite hundreds of definitions, no consensus exists on a definition of life or on the closely related and problematic definitions of the organism and death. These problems retard practical and theoretical development in, for example, exobiology, artificial life, biology and evolution. This paper suggests improving this situation by basing definitions on a theory of a generalized particle hierarchy. This theory uses the common denominator of the “operator” for a unified ranking of both particles and organisms, (...) from elementary particles to animals with brains. Accordingly, this ranking is called “the operator hierarchy”. This hierarchy allows life to be defined as: matter with the configuration of an operator, and that possesses a complexity equal to, or even higher than the cellular operator. Living is then synonymous with the dynamics of such operators and the word organism refers to a select group of operators that fit the definition of life. The minimum condition defining an organism is its existence as an operator, construction thus being more essential than metabolism, growth or reproduction. In the operator hierarchy, every organism is associated with a specific closure, for example, the nucleus in eukaryotes. This allows death to be defined as: the state in which an organism has lost its closure following irreversible deterioration of its organization. The generality of the operator hierarchy also offers a context to discuss “life as we do not know it”. The paper ends with testing the definition’s practical value with a range of examples. (shrink)

Because biologists are concerned with life in all its forms, and physicians deal with life and death on a daily basis, it is crucial that they explicitly understand what life is. Nevertheless, a clear idea of what life means remains elusive, and there is no universally accepted definition. Therefore, we offer our own: Life is a self-contained, self-regulating, self-organizing, self-reproducing, interconnected, open thermodynamic network of component parts which performs work, existing in a complex regime which (...) combines stability and adaptability in the phase transition between order and chaos, as a plant, animal, fungus, or microbe. This definition describes life as we know it here on earth and .. (shrink)

A distinction must be made between various levels of thought. For a definition of life the formulation on the level of natural sciences,i.e. the biological definition, will not be the same as the philosophical expression. The biological definition is based on thephenomenon of life, the appearance, and considers the molecular structure and functions of a cell. The philosophical definition regards thebeing and it is proposed to consider life as transcendental. It is argued that there is no opposition (...) between these definitions, but that together they can deepen our insight into the problems of matter and life. (shrink)

What is the definition of life? Artificial life environments provide an interesting test case for this classical question. Understanding what such systems can tell us about biological life requires negotiating the tricky conceptual boundary between virtual and real life forms. Drawing from Wittgenstein’s analysis of the concept of a game and a Darwinian insight about classification, I argue that classifying life involves both causal and pragmatic elements. Rather than searching for a single, sharp definition, these (...) considerations suggest that life is a cluster concept with fuzzy boundaries and that there are multiple legitimate ways to make the notion precise for different scientific purposes. This pluralist, realist account avoids unnecessary border disputes by emphasizing how science negotiates such questions in relation to theory and evidence. I also discuss several objections to this approach, including a “moral hesitation” some have to allowing broader application of the concept of life to include artificial life. (shrink)

In several disciplines within science—evolutionary biology, molecular biology, astrobiology, synthetic biology, artificial life—and outside science—primarily ethics—efforts to define life have recently multiplied. However, no consensus has emerged. In this article, I argue that this is no accident. I propose a dilemma showing that the project of defining life is either impossible or pointless. The notion of life at stake in this project is either the folk concept of life or a scientific concept. In the former (...) case, empirical evidence shows that life cannot be defined. In the latter case, I argue that, although defining life may be possible, it is pointless. I conclude that scientists, philosophers, and ethicists should discard the project of defining life. (shrink)

Discussions on the status of definitions of life have long been dominated by a position known as definitional pessimism. Per the definitional pessimist, there is no point in trying to define life. This claim is defended in different ways, but one of the shared assumptions of all definitional pessimists is that our attempts to define life are attempts to provide a list of all necessary and sufficient conditions for something to count as alive. In other words, (...) a definition of life is a strict, descriptive definition. Against this, several pragmatic alternatives have been put forward. On these pragmatic accounts, definitions of life are not strictly, but rather loosely descriptive. Their purpose is not to be true, but to be useful to scientists by guiding scientific practice. More recently, this position has come under attack for not being able to explain how our attempts to define life are connected to scientific progress within the biological sciences. Here, I argue to the contrary by showing how pragmatic definitions of life can be, and in fact are, conducive to scientific progress. Additionally, I show how the pragmatic account of definitions of life can be brought to bear upon our normative discussions involving definitions of life. (shrink)

To determine when the life of a human organism begins, Mark T. Brown has developed the somatic integration definition of life. Derived from diagnostic criteria for human death, Brown’s account requires the presence of a life‐regulation internal control system for an entity to be considered a living organism. According to Brown, the earliest point at which a developing human could satisfy this requirement is at the beginning of the fetal stage, and so the embryo is not regarded (...) as a living human organism. This, Brown claims, has significant bioethical implications for both abortion and embryo experimentation. Here, we dispute the cogency of Brown’s derivation. Diagnostic criteria for death are used to determine when an organism irreversibly ceases functioning as an integrated whole, and may vary significantly depending on how developed the organism is. Brown’s definition is derived from a specific definition of death applicable to postnatal human beings, which is insufficient for generating a general definition for human organismal life. We have also examined the bioethical implications of Brown’s view, and have concluded that they are not as significant as he believes. Whether the embryo is classified as a human organism is of peripheral interest—a far more morally relevant question is whether the embryo is a biological individual with an identity that is capable of persisting during development. (shrink)

El objetivo de este artículo es examinar la definición de "vida" en el pensamiento de Helmut Plessner y de Hans Jonas, para, con base en las evidencias biológicas y las reflexiones de estos autores, plantear la pregunta por las categorías fundamentales que diferencian lo vital de lo inerte, que son, a nuestro juicio, tres: la célula como unidad estructural y funcional, la transmisión de información genética, y la evolución por selección natural. The objective of the article is to explore the (...) definition of "life" in the thought of Helmut Plessner and Hans Jonas. On the basis of biological evidence and the authors' reflections, the paper inquires into the three fundamental categories that differentiate living and non-living things: the cell as a structural and functional unit, the transmission of genetic information, and evolution due to natural selection. (shrink)

The somatic integration definition of life is familiar from the debate on the determination of death, with some bioethicists arguing that it supports brain death while others argue that some brain‐dead bodies exhibit sufficient somatic integration for biological life. I argue that on either interpretation, the somatic integration definition of life implies that neither the preimplantation embryo nor the postimplantation embryo meet the somatic integration threshold condition for organismal human life. The earliest point at which a (...) somatic integration determination of life could be made would be the beginning of the fetal stage, 9 weeks postfertilization. Bioethical implications are considered, specifically with respect to the moral status of the postimplantation embryo in embryo research and abortion. (shrink)

We draw on Short’s work on Peirce’s theory of signs to propose a new general definition of interpretation. Short argues that Peirce’s semiotics rests on his naturalised teleology. Our proposal extends Short’s work by modifying his definition of interpretation so as to make it more generally applicable to putatively interpretative processes in biological systems. We use our definition as the basis of an account of different kinds of misinterpretation and we discuss some questions raised by the definition by reference to (...) parallel problems in the field of teleosemantics. We propose that interpretative responses fulfilling the criteria of our definition may be made by relatively simple molecular entities and we suggest two specific empirical applications of the definition to experimental work in the field of origin of life research. Our wider aim is to suggest that a well formulated naturalistic definition of interpretation will allow a re-evaluation of the role of semiotic phenomena in biological systems, including the generation of empirically testable hypotheses. (shrink)

The term “euthanasia” is used in conflicting ways in the bioethical literature, as is the term “assisted suicide,” resulting in definitional confusion, ambiguities, and biases which are counterproductive to ethical and legal discourse. I aim to rectify this problem in two parts. Firstly, I explore a range of conflicting definitions and identify six disputed definitional factors, based on distinctions between (1) killing versus letting die, (2) fully intended versus partially intended versus merely foreseen deaths, (3) voluntary versus nonvoluntary versus (...) involuntary decisions, (4) terminally ill versus non-terminally ill patients, (5) patients who are fully conscious versus those in permanent comas or persistent vegetative states, and (6) patients who are suffering versus those who are not. Secondly, I distil these factors into six “building blocks” and combine them to develop an unambiguous, value-neutral taxonomy of “end-of-life practices.” I hope that this taxonomy provides much-needed clarification and a solid foundation for future ethical and legal discourse. (shrink)

The discovery that the universe is fine-tuned for life ? a discovery to which the phrase ?the anthropic principle? is often applied ? has prompted much extra-cosmic speculation by philosophers, theologians, and theoretical physicists. Such speculation is referred to as extra-cosmic because an inference is made to the existence either of one unobservable entity that is distinct from the cosmos and any of its parts (God) or of many such entities (multiple universes). In this article a case is mounted (...) for the sceptical position that cosmic fine-tuning does not support an inference to anything extra-cosmic. To that end three definitions of ?fine-tuned for life? are proposed: the ?slight difference? definition, the (unconditional) probability definition, and John Leslie?s conditional probability definition. These three definitions are the only ones suggested by the relevant literature on fine-tuning and the anthropic principle. Since on none of them do claims of fine-tuning warrant an inference to something extracosmic, it is concluded that there is no definition of ?fine-tuned for life? serving this function. (shrink)

Modern medicine provides unprecedented opportunities in diagnostics and treatment. However, in some situations at the end of a patient’s life, many physicians refrain from using all possible measures to prolong life. We studied the incidence of different types of treatment withheld or withdrawn in 6 European countries and analyzed the main background characteristics.

The phrase “minimal risk,” as defined in the United States’ federal research regulations, is ambiguous and poorly defined. This article argues that most of the ambiguity that one finds in the phrase stems from the “daily life risks” standard in the definition of minimal risk. In this article, the author argues that the daily life risks standard should be dropped and that “minimal risk” should be defined as simply “the probability and magnitude of the harm or discomfort anticipated (...) in research are not greater than those encountered during the performance of routine physical or psychological examinations or tests”. (shrink)

This paper suggests that medically the term a 'human being' should be defined by the presence of an active human brain. The brain is the only unique and irreplaceable organ in the human body, as the orchestrator of all organ systems and the seat of personality. Thus, the presence or absence of brain life truly defines the presence or absence of human life in the medical sense. When viewed in this way, human life may be seen as (...) a continuous spectrum between the onset of brain life in utero (eight weeks gestation), until the occurrence of brain death. At any point human tissue or organ systems may be present, but without the presence of a functional human brain, these do not constitute a 'human being', at least in a medical sense. The implications of this theory for various ethical concerns such as in vitro fertilisation and abortion are discussed. This theory is the most consistent possible for the definition of a human being with no contradictions inherent. However, having a good theory of definition of a 'human being' does not necessarily solve the ethical problems discussed herein. (shrink)

This dissertation is based on four backgrounds: (1) the diversity of definitions of philosophy, (2) statements by several thingkers about the death/ending of philosophy, (3) the existence of Hassan Hanafi's writings about the definition, life and death of philosophy, and (4) the limitations of specific studies on philosophy according to Hanafi. On that basis, this dissertation examines philosophy according to Hanafi, by revealing and reviewing his definition of philosophy and his views on when philosophy lives and when philosophy (...) dies. In general, this is metaphilosophical study of Hanafi's philosophy by disclosuring it descriptively and analytically on the one side, and by reviewing it falsificatively, interpretatively and axiologically on the other side. This metaphilosophical study of Hanafi philosophy found several things. First, Hanafi's definition of philosophy is still diverse and needs to be reanalyzed, so it cannot overcome the problem of the diversity of definitions of philosophy. Second, Hanafi's statement about those who kill philosophy and turn on it is inconsistent and falsifiable. Third, philosophy can still live in conditions that are considered to kill it. Fourth, although it has several weaknesses, Hanafi's philosophy is useful in particular for Muslims and researchers about Islam, Arab nations and researchers about Arab, and societies that face internal and external traditions; and also worthwhile in general for philosophy and practitioners of philosophy. Fifth, Hanafi's philosophy can overcome the problem of ongoing discourse about the death/ending of philosophy, because his philosophy can actually bring philosophy to life. (shrink)

A compelling collection of the life-changing writings of William James William James—psychologist, philosopher, and spiritual seeker—is one of those rare writers who can speak directly and powerfully to anyone about life’s meaning and worth, and whose ideas change not only how people think but how they live. The thinker who helped found the philosophy of pragmatism and inspire Alcoholics Anonymous, James famously asked, “is life worth living?” Bringing together many of his best and most popular essays, talks, (...) and other writings, this anthology presents James’s answer to that and other existential questions, in his own unique manner—caring, humorous, eloquent, incisive, humble, and forever on the trail of the “ever not quite.” Here we meet a James perfectly attuned to the concerns of today—one who argues for human freedom, articulates a healthy-minded psychology, urges us to explore the stream of consciousness, presents a new definition of truth based on its practical consequences, and never forecloses the possibility of mystical transcendence. Introduced by John Kaag and Jonathan van Belle, these compelling and accessible selections reveal why James is one of the great guides to the business of living. (shrink)

Despite numerous and increasing attempts to define what life is, there is no consensus on necessary and sufficient conditions for life. Accordingly, some scholars have questioned the value of definitions of life and encouraged scientists and philosophers alike to discard the project. As an alternative to this pessimistic conclusion, we argue that critically rethinking the nature and uses of definitions can provide new insights into the epistemic roles of definitions of life for different (...) research practices. This paper examines the possible contributions of definitions of life in scientific domains where such definitions are used most (e.g., Synthetic Biology, Origins of Life, Alife, and Astrobiology). Rather than as classificatory tools for demarcation of natural kinds, we highlight the pragmatic utility of what we call operational definitions that serve as theoretical and epistemic tools in scientific practice. In particular, we examine contexts where definitions integrate criteria for life into theoretical models that involve or enable observable operations. We show how these definitions of life play important roles in influencing research agendas and evaluating results, and we argue that to discard the project of defining life is neither sufficiently motivated, nor possible without dismissing important theoretical and practical research. (shrink)

This chapter contains sections titled: The scaffolding of facts The role of our nature Forms of life Agreement: consensus of human beings and their actions.