The Existential Quantifier, Composition and Contingency

There is a good deal of disagreement about composition. There is first-order disagreement: there are radically different answers to the special composition question—the question of under what circumstances the xs compose a y. There is second-order disagreement: there are different answers to the question of whether first-order disagreement is real or merely semantic. Virtually all disputants with respect to both the first- and second-order issues agree that the answer or answers to the special composition question will take the form of a necessary truth or truths even though, as I will argue, such answers do not appear to be good candidates to be necessary truths. This paper provides an analysis of the concept of <exists> as it pertains to concrete objects, that fulfils two functions. First, it explicates the sense in which claims about composition are contingent and the sense in which they are necessary, and second, it provides a way of understanding when first-order disputes are substantial and when they are merely semantic.     

Quantum gravity,timelessness, and the contents of thought

Philosophical Studies - A number of recent theories of quantum gravity lack a one-dimensional structure of ordered temporal instants. Instead, according to many of these views, our world is either...     

The new growing block theory vs presentism

It was once held to be a virtue of the growing block theory that it combines temporal dynamism with a straightforward account of in virtue of what past-tensed propositions are true, and an explanation for why some future-tensed propositions are not true (assuming they are not). This put the growing block theory ahead of its principal dynamist rival: presentism. Recently, new growing block theorists have suggested that what makes true, past-tensed propositions, is not the same kind of thing as what makes true, present-tensed propositions. They have done so in an attempt to defuse a particular epistemic objection to their view. In this paper it is argued that the new growing block theorist faces a dilemma. The more unified a strategy is for responding to the epistemic objection, the more that strategy results in the new growing block model positing truthmakers that are similar to those posited by the presentist, which erodes the purported advantage of the growing block theory over presentism. On the other hand, versions of the new growing block theory that embrace disunified strategies are better able to differentiate themselves from presentism, but are unattractive because of their disunity.     

The Unique Groundability of Temporal Facts

The A‐theory and the B‐theory advance competing claims about how time is grounded. The A‐theory says that A‐facts are more fundamental in grounding time than are B‐facts, and the B‐theory says the reverse. We argue that whichever theory is true of the actual world is also true of all possible worlds containing time. We do this by arguing that time is uniquely groundable: however time is actually grounded, it is necessarily grounded in that way. It follows that if either the A‐theory or the B‐theory is actually false, then it is necessarily false.     

Belief in robust temporal passage (probably) does not explain future-bias

Philosophical Studies - Empirical work has lately confirmed what many philosophers have taken to be true: people are ‘biased toward the future’. All else being equal, we usually prefer...     

Strategies used by transmasculine and non-binary adults assigned female at birth to resist transgender stigma in healthcare

Abstract

Background: Transgender stigma is rampant within healthcare systems in the United States. Transgender adults assigned female at birth – including those identifying as transmasculine or non-binary – face unique barriers, such as stigma when accessing sexual and reproductive healthcare labeled as being for “women.” However, transgender and non-binary people are not passive victims to this stigma, and the medical community would benefit from understanding the actions this population takes to resist and reduce transgender stigma in healthcare. Yet, little research has attempted to understand such actions.

Aims: This qualitative study aims to explore how transmasculine and non-binary adults are actively resisting and reducing the impact of transgender stigma in healthcare.

Methods: In-depth semi-structured interviews were conducted with 25 transmasculine and non-binary adults assigned female at birth who were living in a metropolitan area in the mid-Atlantic United States. The research team analyzed qualitative interview data using content analysis.

Results: The 25 participants ranged in age from 21 to 57, with an average age of 33?years old. Six themes were identified related to resisting and reducing transgender stigma in healthcare: (a) using social support; (b) persistence to meet one’s own needs; (c) avoiding mainstream healthcare; (d) advocacy; (e) doing one’s own research; and (f) strategic disclosure of transgender/non-binary identity. We detail how privilege and intersectionality connect to the use of these strategies.

Discussion: Findings indicate there is value in using peer advocates and peer health literacy; in developing and nurturing support groups related to transgender/non-binary health; in developing “allies” employed within the healthcare system; in creating and maintaining lists of culturally responsive health providers and resources about navigating the healthcare system; and in offering trainings related to self-advocacy and health-related activism. These findings can be used to inform future health prevention and intervention efforts with transmasculine and non-binary adults.     

Contributions of glucocorticoid receptors in cortical astrocytes to memory recall

Dysfunctions in memory recall lead to pathological fear; a hallmark of trauma-related disorders, like posttraumatic stress disorder (PTSD). Both, heightened recall of an association between a cue and trauma, as well as impoverished recall that a previously trauma-related cue is no longer a threat, result in a debilitating fear toward the cue. Glucocorticoid-mediated action via the glucocorticoid receptor (GR) influences memory recall. This literature has primarily focused on GRs expressed in neurons or ignored cell-type specific contributions. To ask how GR action in nonneuronal cells influences memory recall, we combined auditory fear conditioning in mice and the knockout of GRs in astrocytes in the prefrontal cortex (PFC), a brain region implicated in memory recall. We found that knocking out GRs in astrocytes of the PFC disrupted memory recall. Specifically, we found that knocking out GRs in astrocytes in the PFC (AstroGRKO) after fear conditioning resulted in higher levels of freezing to the CS+ tone when compared with controls (AstroGRintact). While we did not find any differences in extinction of fear toward the CS+ between these groups, AstroGRKO female but not male mice showed impaired recall of extinction training. These results suggest that GRs in cortical astrocytes contribute to memory recall. These data demonstrate the need to examine GR action in cortical astrocytes to elucidate the basic neurobiology underlying memory recall and potential mechanisms that underlie female-specific biases in the incidence of PTSD.

Recalling important information about salient environmental cues is an integral part of how we navigate our world. Recalling too much, or too little, information about salient environmental cues is a part of the psychopathology of posttraumatic stress disorder (PTSD) (Milad and Quirk 2012). More specifically, the augmented recall of an association between an environmental cue and a traumatic event results in debilitating fear toward the cue, even in the absence of any threat. In contrast, impoverished recall of information that a cue, previously associated with trauma, is no longer a threat also results in debilitating fear toward the cue after it is no longer dangerous. Therefore, one way to mitigate debilitating fear that characterizes PTSD is to understand the neurobiological mechanisms underlying memory recall.Among many mechanisms, glucocorticoid action via signaling through glucocorticoid receptors (GRs) is an important neurobiological pathway that underlies the recall of salient information. When trauma-associated cues are encountered, the hypothalamic-pituitary-adrenal axis is activated and GR signaling is consequently triggered (McEwen et al. 1988; McEwen 1992; Lupien et al. 2009). Existing literature demonstrates that glucocorticoids and GRs do in fact influence learning, memory, and the recall of learning (Pugh et al. 1997; de Quervain et al. 1998, 2009, 2011, 2017, 2019; Roozendaal 2002, 2003; Conrad et al. 2004; Hui et al. 2004; Donley et al. 2005; Roozendaal and de Quervain 2005; Cai et al. 2006; Soravia et al. 2006; Yang et al. 2006; Roozendaal et al. 2009; Bentz et al. 2010; Blundell et al. 2011; Clay et al. 2011; Nikzad et al. 2011; Roesler 2012; Liao et al. 2013; Wislowska-Stanek et al. 2013; Arp et al. 2016; Reis et al. 2016; Dadkhah et al. 2018; Inoue et al. 2018; Scheimann et al. 2019; Lin et al. 2020). The relationship between glucocorticoids, GRs, learning and memory is complicated and within the literature cited above, one can find examples of GR action being facilitatory as well as inhibitory to learning and memory recall. As expansive as this research is, the influence of GRs on learning, memory, and recall of learning has mostly focused only on GR action in neurons or has ignored cell type specific contributions. While glia are approximately as common as neurons in the nervous system (von Bartheld et al. 2016; von Bartheld 2018), the role of GRs in glial cells on the recall of salient environmental cues has been neglected. More specifically, while astrocytes comprise a significant proportion of the glial cell population (von Bartheld et al. 2016) and express GRs (Vielkind et al. 1990; Bohn et al. 1991), the influence of GRs in astrocytes on memory recall remains largely unappreciated (for one exception, see the Discussion).Our goal in this study was to determine the influence of GRs in astrocytes on memory recall. To do so, we combined the robust and reliable experimental framework of classical fear conditioning in rodents (Santini et al. 2008; Dias et al. 2014; Bukalo et al. 2015; Keiser et al. 2017; Giustino and Maren 2018; Greiner et al. 2019; Gunduz-Cinar et al. 2019; Venkataraman et al. 2019) with molecular genetic manipulations in the prefrontal cortex (PFC), a brain region critical for the recall of memory (Morgan and LeDoux 1995; Quirk et al. 2000; Mueller et al. 2008; Quirk and Mueller 2008; Giustino and Maren 2015; Rozeske et al. 2015; Maren and Holmes 2016). We first trained mice to associate tone presentations with mild footshocks. After this auditory fear conditioning, we used a CRE-loxP strategy to specifically knock out GRs in astrocytes in the PFC (hereafter termed cortical astrocytes) of these trained mice. We then exposed animals to extinction training: 30 presentations of the tone in the absence of any footshocks. Finally, 1 d after the extinction training, we exposed animals to two presentations of the tone. This experimental timeline allowed us to ask how a lack of GRs in cortical astrocytes influences (1) the recall of the previous aversive association of the tone presentation with the footshock, (2) the extinction of fear that would typically occur during extinction training, and (3) the recall of extinction training allowing us to measure the influence of GRs in cortical astrocytes on the recall of extinction training. Broadly, our results demonstrate that knocking out GRs in cortical astrocytes disrupts fear memory recall in both male and female mice, while only disrupting extinction recall in female mice.