46,005 research outputs found
Phylogeny of the Orangethroat Darter (Etheostoma spectabile) species complex in the Ozark Highlands of Arkansas
Darters are small, benthic fishes that live in freshwater rivers and streams and belong to the family Percidae. Pleistocene glaciations fragmented many darter species, resulting in speciation, but new species are often hard to detect if they are morphologically identical to pre-existing species. Intraspecific hybridization and resulting introgression, which occur frequently in glaciated areas, further complicate identification by introducing heterospecific genomes into mitochondrial DNA, making it difficult to accurately resolve phylogenetic relationships. The results of Bossu and Nearâs 2009 study highlight this issue, showing a large degree of incongruence between mitochondrial and nuclear gene trees.
This study analyzed samples from 50 collection sites along the White River Drainages in the Ozark Highlands region of Arkansas, and area that is high in both species richness and habitat diversity. SVDQuartets analysis genrerating bootstap values for 1000 iterations recovered 12 species of Etheostoma, including 3 from the E. spectabile species complex, which was surprisingly non-monophyletic for the represented taxa. However, the relationships shown in the tree are consistent with previous studies which concluded that heterospecific DNA is being introgressed into the E. spectabile complex, although the sister-species relationships recovered differ from those found in Bossu and Near. The relationships displayed in this tree reveal the tendency for hybridization and introgression to occur between members of E. spectabile and other Etheostoma, however, sampling size and sampling area are both small, and further analysis is needed that includes more individuals and a broader sampling across a wide range of darter habitats to determine if these relationships are representative of the clade as a whole
Reliabilism and Relativism
Process reliabilism says that a belief is justified iff the belief-forming process that produced it is sufficiently reliable. But any token belief-forming process is an instance of a number of different belief-forming process types. The problem of specifying the relevant type is known as the âgenerality problemâ for process reliabilism. This paper proposes a broadly relativist solution to the generality problem. The thought is that the relevant belief-forming process type is relative to the context. While the basic idea behind the solution is from Mark Heller (1995), the solution defended here departs from Heller on a crucial point. Because of this departure, my solution avoids a serious problem with Hellerâs solution
Irrelevant Cultural Influences on Belief
Recent work in psychology on âcultural cognitionâ suggests that our cultural background drives our attitudes towards a range of politically contentious issues in science such as global warming. This work is part of a more general attempt to investigate the ways in which our wants, wishes and desires impact on our assessments of information, events and theories. Put crudely, the idea is that we conform our assessments of the evidence for and against scientific theories with clear political relevance to our pre-existing political beliefs and convictions. In this paper I explore the epistemological consequences of cultural cognition. What does it mean for the rationality of our beliefs about issues such as global warming? I argue for an unsettling conclusion. Not only are those on the âpolitical rightâ who reject the scientific consensus on issues like global warming unjustified in doing so, some of those on the âpolitical leftâ who accept the consensus are also unjustified in doing so. I finish by addressing the practical implications of my conclusions
The Disappearance of Ignorance
Keith DeRoseâs new book The Appearance of Ignorance is a welcome companion volume to his 2009 book The Case for Contextualism. Where latter focused on contextualism as a view in the philosophy of language, the former focuses on how contextualism contributes to our understanding of some perennial epistemological problems, with the skeptical problem being the main focus of six of the seven chapters. DeRoseâs view is that a solution to the skeptical problem must do two things. First, it must explain how it is that we can know lots of things, such as that we have hands. Second, it must explain how it can seem that we donât know these things. In slogan form, DeRoseâs argument is that a contextualist semantics for knowledge attributions is needed to account for the âappearance of ignoranceââthe appearance that we donât know that skeptical hypotheses fail to obtain. In my critical discussion, I will argue inter alia that we donât need a contextualist semantics to account for the appearance of ignorance, and in any case that the âstrengthâ of the appearance of ignorance is unclear, as is the need for a philosophical diagnosis of it
Clifford and the Common Epistemic Norm
This paper develops a âCliffordianâ argument for a common epistemic norm governing belief, action, and assertion. The idea is that beliefs are the sorts of things that lead to actions and assertions. What each of us believes influences what we act on and assert, and in turn influences what those around us believe, act on, and assert. Belief, action, and assertion should be held to a common epistemic norm because, otherwise, this system will become contaminated. The paper finishes by drawing out the relativistic implications of the Cliffordian argument
No Epistemic Trouble for Engineering âWomanâ
In a recent article in this journal, Mona Simion argues that Sally Haslangerâs âengineeringâ approach to gender concepts such as âwomanâ faces an epistemic objection. The primary function of all conceptsâgender concepts includedâis to represent the world, but Haslangerâs engineering account of âwomanâ fails to adequately represent the world because, by her own admission, it doesnât include all women in the extension of the concept âwoman.â I argue that this objection fails because the primary function of gender conceptsâand social kind concepts in generalâis not to represent the world, but rather to shape it. I finish by considering the consequences for âconceptual engineeringâ in philosophy more generally. While Haslangerâs account may escape Simionâs objection, other appeals to conceptual engineering might not fair so well
Braid read-only memory
Transformer-type memory is fault-tolerant array of independent read-only memory units. Information pattern in each unit is written by weaving wires through array of linear (nonswitching) transformers. Presence or absence of a bit is determined by whether a given wire threads or bypasses given transformer
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