One argument Robert and Baylis do not raise in their article on the creation of interspecies chimeras using human cellular material is that the creation of these chimeras would, or could, offend human dignity. Yet, human dignity is one of the most common concerns raised in public debates, academic arguments, and policy documents regarding biotechnology in general, and the creation animal-human chimeras in particular. … The concept is ill-defined within bioethics and … risks being dismissed as meaningless or uselessly vague. (...) However, this lack of definition should not yet cause us to abandon or ignore human dignity. At least in arguments about creating chimeras, an examination of what may be meant by appeals to human dignity can uncover important concerns or arguments that are not captured by other formulations of the debate. (shrink)

Switzerland has very detailed laws regulating the use of animals in agriculture, entertainment and science. There are also many Swiss laws governing the genetic modification of animals, protecting human embryos, and criminalising the creation of human/animal chimeras or hybrids. Despite all these regulations, the creation of an animal embryo that will develop a human organ using induced pluripotent stem cells and the subsequent birth of the resulting chimera would actually be permitted by current legislation. While this might appear to (...) be an unhappy accident due to insufficient scientific foresight, I argue here that this loophole should not be closed, as the creation of human organs inside animals will probably be possible within 10 years, and Swiss laws would currently enable the use of this process to save human lives through this allogenic or autologous organ source. (shrink)

The creation of chimeras by introducing human stem cells into nonhu- man animals has provoked intense concerns. Addressing objections that appeal to human dignity, I focus in this essay on stem cell research intended to generate human neurons in Great Apes and rodents. After considering samples of dignity- based objections from the literature, I examine the underlying assumption that nonhuman animals have lower moral status than personsFwith particular attention to what it means to speak of higher and lower moral statusFbefore (...) evaluating the chimera research in question. I argue that (1) such experiments involving Great Apes should be prohibited out of respect for the research subjects and (2) such experiments involving rodents may or may not be permissible, depending on how we answer unresolved questions regarding rodents’ moral status. In the end, concerns about human dignity prove insignificant. (shrink)

The figure of the chimera animates both mythology and the biotechnological imagination. The mythological construction of animals from the sections or attributes of different species parallels the surgical and genetic manipulations of animals in modern transformations. Chimerization also represents a hybridization that relationally links different species. Both the mythological imagination and biotechnical practice bear heavily on the definition and identity of the human animal. In mythology the chimera links the animal, the human, and the divine. In biotechnology like (...) xenotransplantation and genetic engineering, real patchwork combinations of humans and other animals are constructed. (shrink)

Moral status is the moral value that something has in its own right, independently of the interests or concerns of others. Research using human embryonic stem cells implicates issues about moral status because the current method of extracting hESCs involves the destruction of a human embryo, the moral status of which is contested. Moral status issues can also arise, however, when hESCs are transplanted into embryonic or fetal animals, thereby creating human/ nonhuman stem cell chimeras. In particular, one concern about (...) chimera research is that it could confer upon an animal the moral status of a normal human adult, but then impermissibly fail to accord the animal the protections it merits in virtue of its enhanced status. Understanding the public policy implications of this ethical conclusion is complicated by the fact that certain views about the moral status of the embryo cannot legitimately be used to justify public policy decisions. Arguments like those employed in the abortion debate for the conclusion that abortion should be legally permissible even if abortion is not morally permissible also support, to a more limited degree, a liberal policy on hESC research involving the creation of chimeras. (shrink)

Non-human animal chimeras, containing human neurological cells, have been created in the laboratory. Despite a great deal of debate, the status of such beings has not been resolved. Under normal definitions, such a being could either be unconventionally human or abnormally animal. Practical investigations in animal sentience, artificial intelligence, and now chimera research, suggest that such beings may be assumed to have no legal rights, so philosophy could provide a different answer. In this vein, therefore, we can ask: What (...) would a chimera, if it could think, think about? Thinking is used to capture the phenomena of a novel, chimeric being perceiving its terrible predicament as no more than a laboratory experiment. The creation of a thinking chimera therefore forces us to reconsider our assumptions about what makes human beings (potentially) unique (and other sentient animals different), because, as such, a chimera’s existence bridges our social and legal expectations about definitions of human and animal. Society has often evolved new social norms based on different kinds of (ir)rational contrivances; the imperative of non-contradiction, which is defended here, therefore requires a specific philosophical response to the rights of a thinking chimeric being. (shrink)

Research with human–animal chimera raises a number of ethical concerns, especially when neural stem cells are transplanted into the brains of non-human primates . Besides animal welfare concerns and ethical issues associated with the use of embryonic stem cells, the research is also regarded as controversial from the standpoint of NHPs developing cognitive or behavioural capabilities that are regarded as “unique” to humans. However, scientists are urging to test new therapeutic approaches for neurological diseases in primate models as they (...) better mimic human physiology than all current animal models. As a response, various countries have issued reports on the topic. Our paper summarizes the ethical issues raised by research with human–animal brain chimeras and compares the relevant regulatory instruments and different recommendations issued in national reports from three important European research nations: Germany, Switzerland and the United Kingdom. We assess and discuss the focus and priorities set by the different reports, review various reasons for and perspectives on the importance of the brain in chimera research, and identify critical points in the reports that warrant further specification and debate. (shrink)

Human eggs for basic, fertility and stem-cell research are in short supply. Many experiments that require their use cannot be carried out at present, and, therefore, the benefits that could emerge from these are either delayed or never materialise. This state of affairs is problematic for scientists and patients worldwide, and it is a matter that needs our attention. Recent advances in chimera research have opened the possibility of creating human/non-human animal chimeras intended for human gamete production (chimeras-IHGP). In (...) this paper, I examine four arguments against the creation of such chimeras and prove that all of them are found wanting. I conclude by showing that there is a strong moral reason for scientists to pursue this research avenue. (shrink)

Many people find the notion of blending humans and nonhumans together to create animals whose brains are composed entirely of human brain cells disturbing. I argue that these moral qualms lack adequate justification. I consider a number of reasons for objecting to the creation of such chimeras and argue that none of these reasons withstand scrutiny. I argue that the only plausible objections to these chimeras would require that they possess morally significant properties that would be lacked by similar, non-chimeric (...) animals, but that there is no good reason to think this would be the case. (shrink)

We show that dynamical clustering, where a system segregates into distinguishable subsets of synchronized elements, and chimera states, where differentiated subsets of synchronized and desynchronized elements coexist, can emerge in networks of globally coupled robust-chaos oscillators. We describe the collective behavior of a model of globally coupled robust-chaos maps in terms of statistical quantities and characterize clusters, chimera states, synchronization, and incoherence on the space of parameters of the system. We employ the analogy between the local dynamics of (...) a system of globally coupled maps with the response dynamics of a single driven map. We interpret the occurrence of clusters and chimeras in a globally coupled system of robust-chaos maps in terms of windows of periodicity and multistability induced by a drive on the local robust-chaos map. Our results show that robust-chaos dynamics does not limit the formation of cluster and chimera states in networks of coupled systems, as it had been previously conjectured. (shrink)

The writer responds to the article “Human‐Animal Chimeras: The Moral Insignificance of Uniquely Human Capacities,” by Julian J. Koplin, in the September‐October 2019 issue of the Hastings Center Report.

Discussions about whether new biomedical technologies threaten or violate human dignity are now common. Indeed, appeals to human dignity have played a central role in national and international debates about whether to allow particular kinds of biomedical investigations. The focus of this paper is on chimera research. I argue here that both those who claim that particular types of human-nonhuman chimera research threaten human dignity and those who argue that such threat does not exist fail to make their (...) case. I first introduce some of the arguments that have been offered supporting the claim that the creation of certain sorts of chimeras threatens or violates human dignity. I next present opponents' assessments of such arguments. Finally I critically analyze both the critics' and the supporters' claims about whether chimera research threatens human dignity. (shrink)

Cerebral organoid models in-of-themselves are considered as an alternative to research animal models. But their developmental and biological limitations currently inhibit the probability that organoids can fully replace animal models. Furthermore, these organoid limitations have, somewhat ironically, brought researchers back to the animal model via xenotransplantation, thus creating hybrids and chimeras. In addition to attempting to study and overcome cerebral organoid limitations, transplanting cerebral organoids into animal models brings an opportunity to observe behavioral changes in the animal itself. Traditional animal (...) ethics frameworks, such as the well-known three Rs (reduce, refine, and replace), have previously addressed chimeras and xenotransplantation of tissue. But these frameworks have yet to completely assess the neural-chimeric possibilities. And while the three Rs framework was a historical landmark in animal ethics, there are identifiable gaps in the framework that require attention. The authors propose to utilize an expanded three Rs framework initially developed by David DeGrazia and Tom L. Beauchamp, known as the Six Principles (6Ps). This framework aims to expand upon the three Rs, fill in the gaps, and be a practical means for assessing animal ethical issues like that of neural-chimeras and cerebral organoid xenotransplantation. The scope of this 6Ps application will focus on two separate but recent studies, which were published in 2019 and 2020. First, they consider a study wherein cerebral organoids were grown from donors with Down syndrome and from neurotypical donors. After these organoids were grown and studied, they were then surgically implanted into mouse models to observe the physiological effects and any behavioral change in the chimera. Second, they consider a separate study wherein neurotypical human embryonic stem cell-derived cerebral organoids were grown and transplanted into mouse and macaque models. The aim was to observe if such a transplantation method would contribute to therapies for brain injury or stroke. The authors place both studies under the lens of the 6Ps framework, assess the relevant contexts of each case, and provide relevant normative conclusions. In this way, they demonstrate how the 6Ps could be applied in future cases of neural-chimeras and cerebral organoid xenotransplantation. (shrink)

In “Human‐Animal Chimeras: The Moral Insignificance of Uniquely Human Capacities,” Julian Koplin explores a promising way of thinking about moral status. Without attempting to develop a model in any detail, Koplin picks up Joshua Shepherd's interesting proposal that we think about moral status in terms of the value of different kinds of conscious experience. For example, a being with the most basic sort of consciousness and sentience would have interests that matter morally, while a being whose consciousness featured the riches (...) of loving affection, say, might have greater moral status and therefore deserve some sort of priority if the interests of the two beings conflicted. This approach represents an improvement over the more common, transparently anthropocentric habits of thinking about moral status, whether in connection with evaluating human‐animal chimera research, deciding what one can ethically eat, or pursuing some other moral inquiry. (shrink)

Kant typically is not identified with the tradition of virtue epistemology. Although he may not be a virtue epistemologist in a strict sense, I suggest that intellectual virtues and vices play a key role in his epistemology. Specifically, Kant identifies a serious intellectual vice that threatens to undermine reason, namely enthusiasm (Schwärmerei). Enthusiasts become so enamored with their own thinking that they refuse to subject reason to self-critique. The particular danger of enthusiasm is that reason colludes in its own destruction: (...) enthusiasm occurs when self-conceit and reason’s desire to transcend its boundaries mutually reinforce each other. I conclude by sketching an account of Kantian intellectual virtue that is consistent with Kantian moral virtue. (shrink)

In Greek mythology, the Chimera is a fire-breathing monster with three heads: one of a lion, one of a horned goat, and one of a powerful dragon. Of similar construction is the presence of three structures in US society, whiteness, patriarchy, and capitalism, which are overwhelmingly represented, valued, and espoused when examining areas of progress, i.e., family income, poverty rates, high school and college graduation rates, and home ownership. This modern American three-headed beast controls, manipulates, and permeates all aspects (...) of US society irrespective of class, culture, or gender. Using critical race theory and critical whiteness studies, this critically interpretive parable draws from the ways in which whiteness, patriarchy, and capitalism function in social, cultural, economic, and educational spheres. The parable tells the story of Sue Libertad and analyzes how this metaphorical Chimera, despite its ubiquity, silently permeates all aspects of her life. Not until a tragic outbreak occurs, does the hegemony of this chimera erodes and Sue. (shrink)

Developments in biological technology in the last few decades highlight the surprising and ever-expanding practical benefits of stem cells. With this progress, the possibility of combining human and nonhuman organisms is a reality, with ethical boundaries that are not readily obvious. These inter-species hybrids are of a larger class of biological entities called “chimeras.” As the concept of a human-nonhuman creature is conjured in our minds, either incredulous wonder or grotesque horror is likely to follow. This paper seeks to mitigate (...) those worries and demotivate reasonable concerns raised against chimera research, all the while pressing current ethical positions toward their plausible conclusions. -/- In service of this overall aim, first, I intend to show that chimeras are far less foreign and fantastic in light of recent research in the lab; second, I intend to show that anti-realist (so-called “constructivist”) commitments regarding species ontology render the species distinction (i.e., the divide between human and nonhuman) superfluous as a basis for ethical practice; and third, I discuss some prevailing dignity accounts regarding the practical ethics of the creation, research, and treatment of chimeras. Consequently I intend to show that the adoption of this particular set of views (constructivist ontology, capacity-based ethics) in conjunction with recent research ought to justify a parallel with what we accord to humans persons, and that trajectory allows for cases of moral permissibility. (shrink)

We examine some of Connes’ criticisms of Robinson’s infinitesimals starting in 1995. Connes sought to exploit the Solovay model S as ammunition against non-standard analysis, but the model tends to boomerang, undercutting Connes’ own earlier work in functional analysis. Connes described the hyperreals as both a “virtual theory” and a “chimera”, yet acknowledged that his argument relies on the transfer principle. We analyze Connes’ “dart-throwing” thought experiment, but reach an opposite conclusion. In S , all definable sets of reals (...) are Lebesgue measurable, suggesting that Connes views a theory as being “virtual” if it is not definable in a suitable model of ZFC. If so, Connes’ claim that a theory of the hyperreals is “virtual” is refuted by the existence of a definable model of the hyperreal field due to Kanovei and Shelah. Free ultrafilters aren’t definable, yet Connes exploited such ultrafilters both in his own earlier work on the classification of factors in the 1970s and 80s, and in Noncommutative Geometry, raising the question whether the latter may not be vulnerable to Connes’ criticism of virtuality. We analyze the philosophical underpinnings of Connes’ argument based on Gödel’s incompleteness theorem, and detect an apparent circularity in Connes’ logic. We document the reliance on non-constructive foundational material, and specifically on the Dixmier trace −∫ (featured on the front cover of Connes’ magnum opus) and the Hahn–Banach theorem, in Connes’ own framework. We also note an inaccuracy in Machover’s critique of infinitesimal-based pedagogy. (shrink)

: The transplantation of adult human neural stem cells into prenatal non-humans offers an avenue for studying human neural cell development without direct use of human embryos. However, such experiments raise significant ethical concerns about mixing human and nonhuman materials in ways that could result in the development of human-nonhuman chimeras. This paper examines four arguments against such research, the moral taboo, species integrity, "unnaturalness," and human dignity arguments, and finds the last plausible. It argues that the transfer of human (...) brain or retinal stem cells to nonhuman embryos would not result in the development of human-nonhuman chimeras that denigrate human dignity, provided such stem cells are dissociated. The article provides guidelines that set ethical boundaries for conducting such research that are consonant with the requirements of human dignity. (shrink)

In this contribution to the Common Knowledge symposium “Comparative Relativisim,” Smith argues that relativism is a chimera, half straw man, half red herring. Over the past century, she shows, objections to the supposed position so named have typically involved either crucially improper paraphrases of general observations of the variability and contingency of human perceptions, interpretations, and judgments or dismaying inferences gratuitously drawn from such observations. More recently, the label relativism has been elicited by the display, especially by anthropologists or (...) historians, of attitudes of epistemic tolerance or efforts at explanatory or evaluative symmetry. Objections here commonly involve mistaken, unwarranted universalizing of those attitudes or recommendations. Purported refutations of what is identified as relativism commonly have no force for alleged relativists because relativism-refuters commonly deploy and depend on the very concepts (e.g., truth and reason) and relations (e.g., between what are referred to as facts and evidence) that are at issue. The result is circular argumentation, intellectual nonengagement, and perfect deadlock. Although there are signs that this tragicomic episode of intellectual history has run its course, two contemporary sites of antirelativist energy are worth noting. One is the claim that so-called cultural relativism is refuted by the existence of cognitive universals. The other is the fear that evaluative symmetry leads to ethically or politically debilitating neutrality. Consideration of the nature of cognitive universals indicates that their existence does not contradict observations of the significance of cultural variability. Consideration of anxieties about the supposed quietistic implications of commitments to epistemic tolerance or symmetry indicates that such anxieties are misplaced. (shrink)

Human‐animal chimeras—creatures composed of a mix of animal and human cells—have come to play an important role in biomedical research, and they raise ethical questions. This article focuses on one particularly difficult set of questions—those related to the moral status of human‐animal chimeras with brains that are partly or wholly composed of human cells. Given the uncertain effects of human‐animal chimera research on chimeric animals’ cognition, it would be prudent to ensure we do not overlook or underestimate their moral (...) status. However, to assess moral status, we first need to determine what kinds of capacities are morally relevant. The standard view holds that it matters, morally, if chimeric animals develop uniquely human cognitive capacities. I argue that this view is mistaken, highlighting three problems with it: that we can think of examples of uniquely human cognitive capacities that are not morally significant, that we can think of examples of morally significant cognitive capacities that are not uniquely human, and that evidence that some cognitive capacity is shared with nonhuman animals does not undermine claims that this capacity is morally significant. We need a better framework for thinking about the moral status of part‐human beings. (shrink)

The burgeoning field of biomedical research involving the mixture of human and animal materials has attracted significant ethical controversy. Due to the many dimensions of potential ethical conflict involved in this type of research, and the wide variety of research projects under discussion, it is difficult to obtain an overview of the ethical debate. This paper attempts to remedy this by providing a systematic review of ethical reasons in academic publications on human-animal chimera research. We conducted a systematic review (...) of the ethical literature concerning human-animal chimeras based on the research question: “What ethical reasons have been given for or against conducting human-animal chimera research, and how have these reasons been treated in the ongoing debate?” Our search extends until the end of the year 2017, including MEDLINE, Embase, PhilPapers and EthxWeb databases, restricted to peer-reviewed journal publications in English. Papers containing ethical reasons were analyzed, and the reasons were coded according to whether they were endorsed, mentioned or rejected. Four hundred and thirty-one articles were retrieved by our search, and 88 were ultimately included and analyzed. Within these articles, we found 464 passages containing reasons for and against conducting human-animal chimera research. We classified these reasons into five categories and, within these, identified 12 broad and 31 narrow reason types.15% of the retrieved passages contained reasons in favor of conducting chimera research, while 85% of the passages contained reasons against it. The reasons against conducting chimera research fell into four further categories: reasons concerning the creation of a chimera, its treatment, reasons referring to metaphysical or social issues resulting from its existence and to potential downstream effects of chimera research. A significant proportion of identified passages fell under Category C. We hope that our results, in revealing the conceptual and argumentative structure of the debate and highlighting some its most notable tendencies and prominent positions, will facilitate continued discussion and provide a basis for the development of relevant policy and legislation. (shrink)

The prospect of creating and using human–animal chimeras and hybrids that are significantly human-like in their composition, phenotype, cognition, or behavior meets with divergent moral judgments: on the one side, it is claimed that such beings might be candidates for human-analogous rights to protection and care; on the other side, it is supposed that their existence might disturb fundamental natural and social orders. This paper tries to show that both positions are paradoxically intertwined: they rely on two kinds of species (...) arguments, “individual species arguments” and “group species arguments,” which formulate opposing demands but are conceptually interdependent. As a consequence, the existence of HACHs may challenge exactly those normative standards on which the protection of HACHs may eventually be based. This ethical paradox could constitute the ultimate source of the “moral confusion” that some authors have suspected HACHs to provoke. (shrink)

This work was supported, in part, by a Stem Cell Network grant to Françoise Baylis and Jason Scott Robert and a CIHR grant to Françoise Baylis. We sincerely thank Alan Fine, Rich Campbell, Cynthia Cohen, and Tim Krahn for helpful comments on an earlier draft of this paper. Thanks are also owed to Tim Krahn for his research assistance. An earlier version of this paper was presented to the Department of Bioethics and the Novel Tech Ethics research team. We thank (...) the participants at each of these meetings for their helpful comments. (shrink)

This paper addresses several questions related to the nature, production, and use of animal-human (a-h) chimeras. At the heart of the issue is whether certain types of a-h chimeras should be brought into existence, and, if they are, how we should treat such creatures. In our current research environment, we recognize a dichotomy between research involving nonhuman animal subjects and research involving human subjects, and the classification of a research protocol into one of these categories will trigger different ethical standards (...) as to the moral permissibility of the research in question. Are a-h chimeras entitled to the more restrictive and protective ethical standards applied to human research subjects? We elucidate an Aristotelian-Thomistic metaphysical framework in which to argue how such chimeras ought to be defined ontologically. We then examine when the creation of, and experimentation upon, certain types of a-h chimeras may be morally permissible. (shrink)

Human–nonhuman chimeras have been the focus of ethical controversies for more than a decade, yet some related issues remain unaddressed. For example, little has been said about the relationship between the origin of transferred cells and the morally relevant capacities to which they may give rise. Consider, for example, a developing mouse fetus that receives a brain stem cell transplant from a human and another that receives a brain stem cell transplant from a dolphin. If both chimeras acquire morally relevant (...) capacities as a result of transplantation, and if those capacities are indistinguishable, should the difference in cell origin matter to how we classify these creatures? I argue that if morally relevant capacities are easy to detect, cell origin is irrelevant to how the chimera ought to be treated. However, if such capacities are hard to detect, cell origin should play a role in considerations about how to treat the chimera. (shrink)

The International Society for Stem Cell Research (ISSCR) has recently released the 2021 update of its guidelines. The update includes detailed new recommendations on human–animal chimera research. This paper argues that the ISSCR recommendations fail to address the core ethical concerns raised by neurological chimeras—namely, concerns about moral status. In minimising moral status concerns, the ISSCR both breaks rank with other major reports on human–animal chimera research and rely on controversial claims about the grounds of moral status that (...) many people will rightly reject. A more robust framework for regulating human–animal chimera research still needs to be developed. (shrink)

Xenotransplantation is often deemed morally objectionable because of the costs it imposes on the organ donor and the risks it imposes on the recipient. For some, involving human–pig chimeras as donors makes the practice more objectionable or even abhorrent from the start. For others, by contrast, using such chimeras weakens recipient-based objections because it reduces the risk of organ rejection and malfunctioning, and cancels donor-based objections because the practice does not harm chimeras but instead gives them valuable lives they would (...) not otherwise have. The paper examines and eventually rejects the latter defense. It also discusses the additional risks of chimeric xenotourism in countries with less demanding procedural guidelines and reflects on two very different futures for humanity that may emerge from supporting or rejecting chimeric xenotransplantation. (shrink)

I argue that chimericity is a property that we typically experience when listening to multi-instrumental music. It is the property of hearing as a unified whole a melody or a harmony that does not belong to any single sound source but instead consists of the assembling of melodic or harmonic fragments coming from different sources. Chimericity is not reducible to the low-level audible properties of pitch and loudness; it is cognized at the perceptual level thanks to the auditory mechanism of (...) primitive grouping. My aim is to show that chimericity is a perceptual property, one that we can genuinely hear. In developing this view, I engage with the debate within the philosophy of sense perception between rich vs thin views of the content of perceptual experience. (shrink)

The paper discusses Husserl’s criticism of Frege in Philosophy of Arithmetic (1891) and then his later attitude towards logicism as expressed in Logical Investigations (1900-01). In Philosophy of Arithmetic Husserl holds that logicists offer needless and artificial definitions of notions such as equivalence and number. Frege criticized Husserl’s approach in Philosophy of Arithmetic as psychological, thus shifting the focus of the debate away from logicism. However, Frege’s criticism could be seen to lead Husserl to his later transcendental phenomenological concept of (...) correlation and, with it, to a more developed criticism of logicism. In this regard the division of labor between mathematics and philosophy established in Prolegomena to the Logical Investigations (1900) is central. It implies that in Husserl’s view formal methods fail to shed philosophical insight into the essence of mathematics. In his picture the central notions in need of philosophical clarification are, instead of number and quantity, the notions that are central to abstract structural mathematics. Contrary to Frege who can only elucidate the primitive concepts, Husserl engages in detailed description of their constitution. (shrink)

Genetic engineering often generates fear of out of control scientists creating Frankenstein creatures that will terrorize the general populace, especially in the cases of human-animal chimeras. While sometimes an accurate characterization of some researchers, this belief is often the result of repugnance for new technology rather than being rationally justified. To facilitate thoughtful discussion the moral issues raised by human-animal chimeras, ethicists and other stakeholders must develop a rational ethical framework before raw emotion has a chance of becoming the dominating (...) justification for public opinion and policy. Derek Parfit’s work on lives worth living for human beings can provide valuable insight into the morality of creating chimeras. As long as their lives are overall good, then bringing them into existence does not harm them even if they are used for medical research or procedures, or they are created to carry on the homo sapiens’ “family” line. (shrink)

The relationship of embryonal carcinoma (EC) cells, the stem cells of germ cell‐ or embryo‐derived teratocarcinoma tumors, to early embryonic cells came under intense scrutiny in the early 1970s when mouse chimeras were produced between EC cells and embryos. These chimeras raised tantalizing possibilities and high hopes for different areas of research. The normalization of EC cells by the embryo lent validity to their use as in vitro models for embryogenesis and indicated that they might reveal information about the relationship (...) between malignancy and differentiation. Chimeras also showed the way for the potential introduction of genes, selected in EC cells in vitro, into the germ line of mice. Although EC cells provided material for the elucidation of early embryonic events and stimulated many studies of early molecular differentiation, after years of intense scrutiny, they fell short as the means of genetic manipulation of the germ line, although arguably they pointed the way to the development of embryonic stem (ES) cells that eventually fulfilled this goal. (shrink)

Earman and Ruetsche ([2005]) have cast their gaze upon existing no-go theorems for relativistic modal interpretations, and have found them inconclusive. They suggest that it would be more fruitful to investigate modal interpretations proposed for "really relativistic theories," that is, algebraic relativistic quantum field theories. They investigate the proposal of Clifton ([2000]), and extend Clifton's result that, for a host of states, his proposal yields no definite observables other than multiples of the identity. This leads Earman and Ruetsche to a (...) suspicion that troubles for modal interpretations of such relativistic theories "are due less to the Poincaré invariance of relativistic QFT vs. the Galilean invariance of ordinary nonrelativistic QM than to the infinite number of degrees of freedom of former vs. the finite number of degrees of freedom of the latter" (577-78). I am skeptical of this suggestion. Though there are troubles for modal interpretations of a relativistic quantum field theory that are due to its being a field theory—that is, due to infinitude of the degrees of freedom—they are not the only troubles faced by modal interpretations of quantum theories set in relativistic spacetime; there are also troubles traceable to relativistic causal structure. (shrink)

In his book Perché ancora la filosofia Carlo Cellucci argues that truth does not play any role in (modern) science: truth is only a chimera that prevents us «from adequately understanding the character of knowledge» and therefore «must be disposed of». I summarize Cellucci’s evidence for his contention that truth is a chimera. I then raise four objections to Cellucci’s views on truth. My conclusion is that, Cellucci’s arguments notwithstanding, a notion of truth is necessary for the human (...) activity of problem solving and therefore for an adequate understanding of the phenomenon of knowledge. (shrink)

Why do laws and regulations marking boundaries between humans and other animals proliferate amid widespread proclamations of the waning of the species concept and the consensus that life is a continuum? Here I consider a recent spate of new guidelines and regulations in the United Kingdom and United States that work to estrange human bodies from other animals in biomedicine. Using the idea of a bioconstitutional moment to understand how state institutions deliberate over “human–animal chimeras,” I address how nations differently (...) establish separations between humans and other animals. New chimeric entities, containing human hereditary material, have consecrated regulatory ground and signify increased attention to fields of research that have long used interspecies mixing. Regulators and policy makers now find themselves in a curious position. On the one hand, they continue to regulate the estrangement between humans and other animals, but on the other, they support the creation of chimeric life––a form of life that draws into question the very basis of such separations. (shrink)

In this paper I explore some of the moral issues that could emerge from the creation of human–nonhuman chimeras capable of human gamete production and human pregnancy. First I explore whether there is a cogent argument against the creation of HNH-chimeras that could produce human gametes. I conclude that so far there is none, and that in fact there is at least one good moral reason for producing such types of creatures. Afterwards I explore some of the moral problems that (...) could emerge from the fact that a HNH-chimera could become pregnant with a human conceptus. I focus on two sets of problems: problems that would arise by virtue of the fact that a human is gestated by a nonhuman creature, and problems that would emerge from the fact that such pregnancies could affect the health of the HNH-chimera. (shrink)

Prima facie it seems easy to understand what he had in mind when he spoke of accidental being and being as true. Accidental or incidental being, what the Latins would later call ens per accidens, was in fact a juxtaposition of two or more categorical beings. As such it lacked a unified essence and thus it lacked genuine being. It was being "only in name." Being as true, he told us, was in the synthesis of the intellect, that is, the (...) intellect's second operation of judgment. Apparently, it was the being of the copula "is" in a true judgment. Contrasted with this was being as false, or pseudo-being, which strictly is nonbeing, found in the copula of a false judgment. (shrink)