Where Tracking Loses Traction

Episteme ◽  
2020 ◽  
pp. 1-14
Author(s):  
Mitchell Barrington

Abstract Tracking theories see knowledge as a relation between a subject's belief and the truth, where the former is responsive to the latter. This relationship involves causation in virtue of a sensitivity condition, which is constrained by an adherence condition. The result is what I call a stable causal relationship between a fact and a subject's belief in that fact. I argue that when we apprehend the precise role of causation in the theory, previously obscured problems pour out. This paper presents 13 distinct and original counterexamples to Nozick's tracking theory – many of which also constitute problems for more recent tracking theories. I begin by discussing how tracking relates to causation: Nozick invokes causation through conditions similar to those of Lewisian causal dependence. As a result, when causal dependence is not necessary for causation, Nozick fails to identify knowledge. I then address the inability of causation to capture epistemically important concepts, such as justification and truth. I conclude by discussing the underlying asymmetries between causation and knowledge that undermine any attempt to reduce knowledge to a purely metaphysical relation.

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2258
Author(s):  
Yu Wang ◽  
Bei Tan ◽  
Yi Wang ◽  
Zhong Chen

Epilepsy is a common brain disorder characterized by recurrent epileptic seizures with neuronal hyperexcitability. Apart from the classical imbalance between excitatory glutamatergic transmission and inhibitory γ-aminobutyric acidergic transmission, cumulative evidence suggest that cholinergic signaling is crucially involved in the modulation of neural excitability and epilepsy. In this review, we briefly describe the distribution of cholinergic neurons, muscarinic, and nicotinic receptors in the central nervous system and their relationship with neural excitability. Then, we summarize the findings from experimental and clinical research on the role of cholinergic signaling in epilepsy. Furthermore, we provide some perspectives on future investigation to reveal the precise role of the cholinergic system in epilepsy.


2005 ◽  
Vol 25 (23) ◽  
pp. 10315-10328 ◽  
Author(s):  
Yukinori Minoshima ◽  
Tetsuya Hori ◽  
Masahiro Okada ◽  
Hiroshi Kimura ◽  
Tokuko Haraguchi ◽  
...  

ABSTRACT We identified CENP-50 as a novel kinetochore component. We found that CENP-50 is a constitutive component of the centromere that colocalizes with CENP-A and CENP-H throughout the cell cycle in vertebrate cells. To determine the precise role of CENP-50, we examined its role in centromere function by generating a loss-of-function mutant in the chicken DT40 cell line. The CENP-50 knockout was not lethal; however, the growth rate of cells with this mutation was slower than that of wild-type cells. We observed that the time for CENP-50-deficient cells to complete mitosis was longer than that for wild-type cells. Centromeric localization of CENP-50 was abolished in both CENP-H- and CENP-I-deficient cells. Coimmunoprecipitation experiments revealed that CENP-50 interacted with the CENP-H/CENP-I complex in chicken DT40 cells. We also observed severe mitotic defects in CENP-50-deficient cells with apparent premature sister chromatid separation when the mitotic checkpoint was activated, indicating that CENP-50 is required for recovery from spindle damage.


2000 ◽  
Vol 69 (Supplement) ◽  
pp. S414-S415
Author(s):  
Xin Xiao Zheng ◽  
Thomas A. Markees ◽  
Martina Weber ◽  
Xian Chang Li ◽  
Yongsheng Li ◽  
...  

1935 ◽  
Vol 31 (3-4) ◽  
pp. 533-533
Author(s):  
Н. Lotze

A. advocates the theory of Pettenkofer about the role of soil in the emergence of epidemics.


2004 ◽  
Vol 167 (1) ◽  
pp. 75-85 ◽  
Author(s):  
Brenton L. Scott ◽  
Jeffrey S. Van Komen ◽  
Hassan Irshad ◽  
Song Liu ◽  
Kirilee A. Wilson ◽  
...  

Sec1 proteins are critical players in membrane trafficking, yet their precise role remains unknown. We have examined the role of Sec1p in the regulation of post-Golgi secretion in Saccharomyces cerevisiae. Indirect immunofluorescence shows that endogenous Sec1p is found primarily at the bud neck in newly budded cells and in patches broadly distributed within the plasma membrane in unbudded cells. Recombinant Sec1p binds strongly to the t-SNARE complex (Sso1p/Sec9c) as well as to the fully assembled ternary SNARE complex (Sso1p/Sec9c;Snc2p), but also binds weakly to free Sso1p. We used recombinant Sec1p to test Sec1p function using a well-characterized SNARE-mediated membrane fusion assay. The addition of Sec1p to a traditional in vitro fusion assay moderately stimulates fusion; however, when Sec1p is allowed to bind to SNAREs before reconstitution, significantly more Sec1p binding is detected and fusion is stimulated in a concentration-dependent manner. These data strongly argue that Sec1p directly stimulates SNARE-mediated membrane fusion.


2011 ◽  
Vol 58 (2) ◽  
pp. 229-244 ◽  
Author(s):  
Nina Ponikvar ◽  
Maks Tajnikar

The aim of this paper is to identify factors that affect the pricing policy in Slovenian manufacturing firms in terms of the markup size and, most of all, to explicitly account for the possibility of differences in pricing procedures among manufacturing industries. Accordingly, the analysis of the dynamic panel is carried out on an industry-by-industry basis, allowing the coefficients on the markup determinants to vary across industries. We find that the oligopoly theory of markup determination for the most part holds for the manufacturing sector as a whole, although large variability in markup determinants exists across industries within the Slovenian manufacturing. Our main conclusion is that each industry should be investigated separately in detail in order to assess the precise role of markup factors in the markup-determination process.


2019 ◽  
Author(s):  
Yann Iboudo ◽  
Melanie E. Garrett ◽  
Pablo Bartolucci ◽  
Carlo Brugnara ◽  
Clary B. Clish ◽  
...  

ABSTRACTIn a recent clinical trial, the metabolite L-glutamine was shown to reduce painful crises in sickle cell disease (SCD) patients. To confirm this observation and identify other metabolites implicated in SCD clinical heterogeneity, we profiled 129 metabolites in the plasma of 705 SCD patients. We tested correlations between metabolite levels and six SCD-related complications (painful crises, cholecystectomy, retinopathy, leg ulcer, priapism, aseptic necrosis) or estimated glomerular filtration rate (eGFR), and used Mendelian randomization (MR) to assess causality. We found a causal relationship between L-glutamine levels and painful crises (N=1,278, odds ratio (OR) [95% confidence interval] = 0.68 [0.52 – 0.89], P=0.0048). In two smaller SCD cohorts (N=299 and 406), the protective effect of L-glutamine was observed (OR=0.82 [0.50-1.34]), although the MR result was not significant (P=0.44). We identified 66 significant correlations between the levels of other metabolites and SCD-related complications or eGFR. We tested these correlations for causality using MR analyses and found no significant causal relationship. The baseline levels of quinolinic acid was associated with prospectively ascertained survival in SCD patients, and this effect was dependent on eGFR. Metabolomics provide a promising approach to prioritize small molecules that may serve as biomarkers or drug targets in SCD.


2000 ◽  
Vol 4 (4) ◽  
pp. 337-354 ◽  
Author(s):  
Vivian L. Vignoles ◽  
Xenia Chryssochoou ◽  
Glynis M. Breakwell

Extending theories of distinctiveness motivation in identity (Breakwell, 1987; Brewer, 1991; Snyder & Fromkin, 1980), we discuss the precise role of distinctiveness in identity processes and the cross-cultural generality of the distinctiveness principle. We argue that (a) within Western cultures, distinctiveness is necessaryfor the construction of meaning within identity, and (b) the distinctiveness principle is not incompatible with non-Western cultural systems. We propose a distinction among three sources of distinctiveness: position, difference, and separateness, with different implications for identity and behavior. These sources coexist within cultures, on both individual and group levels of selfrepresentation, but they may be emphasized differently according to culture and context.


1978 ◽  
Vol 76 (1) ◽  
pp. 149-165 ◽  
Author(s):  
G. M. HUGHES ◽  
G. A. VERGARA

1. Static pressure/volume curves have been determined for isolated frog lungs inflated with either air or saline. In both cases a hysteresis was present: the pressure required to produce unit change of volume being greater during inflation than deflation. 2. The pressure necessary for a given volume change was less for the saline-filled than the air-filled lungs. The difference between these curves is due to the surface tension at the air/lung interface. 3. Pressure/volume curves for air-filled lungs in situ were similar to curves for isolated lungs. However, a greater pressure was required for the same volume change during both inflation and deflation. 4. Compliance was calculated from different parts of air pressure/volume curves and gave values greater than those obtained using similar calculations for higher vertebrates. 5. These observations support other evidence for the presence of a surfactant in the lung lining of frogs in spite of the relatively large diameter of their ‘alveoli.’ The precise role of such a lining is uncertain and it is concluded that similar forces may be involved during the inflation and deflation of lungs of frogs and higher vertebrates in spite of differences in gross morphology.


Author(s):  
Jean-Luc Marion

Marion criticizes the distinction between clerics and laity, which turns the layperson into a militant defender of the faith and ignores the priestly function they already have in virtue of their baptism. It turns clerics into officials dependent on the laity instead of the ones who administer the sacraments. The two kinds of priesthood (baptismal and presbyteral) are linked. We must convert ourselves and the world. The priest calls the assembly together only in the Name of Christ. The priest is in service of the community, helping the baptized to grow into Christ. We become Christian only through imitation of Christ. The proper role of the baptized Christian is to communicate Christ to the world by converting himself.


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