On the Authenticity of De-Extinct Organisms, and the Genesis Argument

Are the methods of synthetic biology capable of recreating authentic living members of an extinct species? An analogy with the restoration of destroyed natural landscapes suggests not. The restored version of a natural landscape will typically lack much of the aesthetic value of the original landscape because of the different historical processes that created it—processes that involved human intentions and actions, rather than natural forces acting over millennia. By the same token, it would appear that synthetically recreated versions of extinct natural organisms will also be less aesthetically valuable than the originals; that they will be, in some strong sense, ‘inauthentic’, because of their peculiar history and mode of origin. I call this the ‘genesis argument’ against de-extinction. In this article I critically evaluate the genesis argument. I highlight an important disanalogy between living organisms and natural landscapes: viz., it is of the essence of the former, but not of the latter, to regularly reproduce and die. The process of iterated natural reproduction that sustains the continued existence of a species through time obviously does not undermine the authenticity of the species. I argue that the authenticity of a species will likewise be left intact by the kind of artificial copying of genes and traits that a de-extinction project entails. I conclude on this basis that the genesis argument is unsound

The Eightfold Way: Why Analyticity, Apriority and Necessity are Independent

This paper concerns the three great modal dichotomies: (i) the necessary/contingent dichotomy; (ii) the a priori/empirical dichotomy; and (iii) the analytic/synthetic dichotomy. These can be combined to produce a tri-dichotomy of eight modal categories. The question as to which of the eight categories house statements and which do not is a pivotal battleground in the history of analytic philosophy, with key protagonists including Descartes, Hume, Kant, Kripke, Putnam and Kaplan. All parties to the debate have accepted that some categories are void. This paper defends the contrary view that all eight categories house statements—a position I dub ‘octopropositionalism’. Examples of statements belonging to all eight categories are given

Does the solar system compute the laws of motion?

The counterfactual account of physical computation is simple and, for the most part, very attractive. However, it is usually thought to trivialize the notion of physical computation insofar as it implies ‘limited pancomputationalism’, this being the doctrine that every deterministic physical system computes some function. Should we bite the bullet and accept limited pancomputationalism, or reject the counterfactual account as untenable? Jack Copeland would have us do neither of the above. He attempts to thread a path between the two horns of the dilemma by buttressing the counterfactual account with extra conditions intended to block certain classes of deterministic physical systems from qualifying as physical computers. His theory is called the ‘algorithm execution account’. Here we show that the algorithm execution account entails limited pancomputationalism, despite Copeland’s argument to the contrary. We suggest, partly on this basis, that the counterfactual account should be accepted as it stands, pancomputationalist warts and all

Why Katz is Wrong: A Lab-Created Creature Can Still Have an Ancient Evolutionary History

Katz denies that organisms created in a lab as part of a de-extinction attempt will be authentic members of the extinct species, on the basis that they will lack the original species’ defining biological and evolutionary history. Against Katz, I note that an evolutionary lineage is conferred on an organism through its inheriting genes from forebears already possessed of such a lineage, and that de-extinction amounts to a delayed, human-assisted reproductive process, in which genes are inherited from forebears long dead. My conclusion is that de-extinct organisms can perfectly well have an ancient evolutionary history, contrary to what Katz claims

Against Lewis on ‘Desire as Belief’

David Lewis describes, then attempts to refute, a simple anti-Humean theory of desire he calls ‘Desire as Belief’. Lewis’ critics generally accept that his argument is sound and focus instead on trying to show that its implications are less severe than appearances suggest. In this paper I argue that Lewis’ argument is unsound. I show that it rests on an essential assumption that can be straightforwardly proven false using ideas and principles to which Lewis is himself committed

Landscape Influence on Canis Morphological and Ecological Variation in a Coyote-Wolf C. lupus × latrans Hybrid Zone, Southeastern Ontario

The ecology of Coyote-Wolf (Canis latrans × C. lupus) hybrids has never fully been typified. We studied morphological and ecological variation in Canis within a region of Coyote-Wolf hybridization in southeastern Ontario. We assessed Canis morphology from standard body measurements and ten skull measurements of adult specimens and found that Canis in this region are morphologically intermediate between Algonquin Provincial Park Wolves (C. lupus lycaon) and Coyotes, indicating a latrans × lycaon hybrid origin; however, there is a closer morphological affinity to latrans than lycaon. Analysis of 846 scats indicated dietary habits also intermediate between lycaon and Coyotes. We used a geographic information system (GIS) to assess spatial landscape features (road density, land cover and fragmentation) for six study sites representing three landscape types. We found noticeable variation in Canis morphology and diet in different landscape types. In general, canids from landscape type A (lowest road density, more total forest cover, less fragmentation) displayed more Wolf-like body morphology and consumed a greater proportion of larger prey (Beaver [Castor canadensis] and White-tailed Deer [Odocoileus virginianus]). In comparison, canids from landscape types B and C (higher road density and/or less total forest cover, more fragmentation) were generally more Coyote-like in body and skull morphology and made greater use of medium to small-sized prey (Groundhog [Marmota monax], Muskrat [Ondatra zibethicus] and lagomorphs). These landscape trends in Canis types suggest selection against Wolf-like traits in fragmented forests with high road density. The range of lycaon southeast of Algonquin Provincial Park appears to be limited primarily due to human access and consequent exploitation. We suggest that road density is the best landscape indicator of Canis types in this region of sympatric, hybridizing and unprotected Canis populations

Detecting West Nile Virus in Owls and Raptors by an Antigen-capture Assay

We evaluated a rapid antigen-capture assay (VecTest) for detection of West Nile virus in oropharyngeal and cloacal swabs, collected at necropsy from owls (N = 93) and raptors (N = 27). Sensitivity was 93.5%–95.2% for northern owl species but <42.9% for all other species. Specificity was 100% for owls and 85.7% for raptors

Conquest and Form: Narrativity in Joshua 5-11 and Historical Discourse in Ancient Judah

One goal of this essay is to offer an exploratory, historiographical analysis of the conquest account in the book of Joshua, an analysis that focuses upon the sociocultural milieu of ancient Judah. I propose to show how this narrative of conquest might have contributed to discourse(s) among the literate Judean community that perpetuated the text, and I will offer a few thoughts on the potential relationship between the narrative and the supposed cultic reforms of the late seventh century b.c.e. A number of biblical scholars have argued that the late monarchic period gave rise to the conquest story as recounted in Joshua. In this essay, I would like to pay special attention to precisely how this narrative might have functioned within the milieu of the late monarchic period, thus refining our understanding of the narrative’s contribution to the discourses of this era and our knowledge of its relationship to other narratives that were probably extant at the same time. In other words, what particular features of the narrative might have had special import in this period? Specifically, I will argue that the narrative reveals certain discursive statements about Yahweh’s cultic supremacy and about important cultic sites in late monarchic Judah, and that this is evident in particular narratival features that are present in the text

Short-term variability in Greenland Ice Sheet motion forced by time-varying meltwater inputs: implications for the relationship between subglacial drainage system behavior and ice velocity.

High resolution measurements of ice motion along a -120 km transect in a land-terminating section of the GrIS reveal short-term velocity variations (<1 day), which are forced by rapid variations in meltwater input to the subglacial drainage system from the ice sheet surface. The seasonal changes in ice velocity at low elevations (<1000 m) are dominated by events lasting from 1 day to 1 week, although daily cycles are largely absent at higher elevations, reflecting different patterns of meltwater input. Using a simple model of subglacial conduit behavior we show that the seasonal record of ice velocity can be understood in terms of a time-varying water input to a channelized subglacial drainage system. Our investigation substantiates arguments that variability in the duration and rate, rather than absolute volume, of meltwater delivery to the subglacial drainage system are important controls on seasonal patterns of subglacial water pressure, and therefore ice velocity. We suggest that interpretations of hydro-dynamic behavior in land-terminating sections of the GrIS margin which rely on steady state drainage theories are unsuitable for making predictions about the effect of increased summer ablation on future rates of ice motion. © 2012. American Geophysical Union

Exploring causality in the association between circulating 25-hydroxyvitamin D and colorectal cancer risk:a large Mendelian randomisation study

Background: Whilst observational studies establish that lower plasma 25-hydroxyvitamin D (25-OHD) levels are associated with higher risk of colorectal cancer (CRC), establishing causality has proven challenging. Since vitamin D is modifiable, these observations have substantial clinical and public health implications. Indeed, many health agencies already recommend supplemental vitamin D. Here, we explore causality in a large Mendelian randomisation (MR) study using an improved genetic instrument for circulating 25-OHD. Methods: We developed a weighted genetic score for circulating 25-OHD using six genetic variants that we recently reported to be associated with circulating 25-OHD in a large genome-wide association study (GWAS) meta-analysis. Using this score as instrumental variable in MR analyses, we sought to determine whether circulating 25-OHD is causally linked with CRC risk We conducted MR analysis using individual-level data from 10,725 CRC cases and 30,794 controls (Scotland, UK Biobank and Croatia). We then applied estimates from meta-analysis of 11 GWAS of CRC risk (18,967 cases; 48,168 controls) in a summary statistics MR approach. Results: The new genetic score for 25-OHD was strongly associated with measured plasma 25-OHD levels in 2821 healthy Scottish controls (P = 1.47 x 10(-11)), improving upon previous genetic instruments (F-statistic 46.0 vs. 13.0). However, individual-level MR revealed no association between 25-OHD score and CRC risk (OR 1.03/unit log-transformed circulating 25-OHD, 95% CI 0.51-2.07, P= 0.93). Similarly, we found no evidence for a causal relationship between 25-OHD and CRC risk using summary statistics MR analysis (OR 0.91, 95% CI 0.69-1.19, P= 0.48). Conclusions: Despite the scale of this study and employing an improved score capturing more of the genetic contribution to circulating 25-OHD, we found no evidence for a causal relationship between circulating 25-OHD and CRC risk Although the magnitude of effect for vitamin D suggested by observational studies can confidently be excluded, smaller effects sizes and non-linear relationships remain plausible. Circulating vitamin D may be a CRC biomarker, but a causal effect on CRC risk remains unproven