Adams Thesis and the Local Interpretation of Conditionals

Adams' Thesis states that the probability of a conditional is the probability of the consequent conditional on the antecedent. S. Kaufmann introduced a rival method, the so-called ``local interpretation'', for calculating the probability of a conditional that, according to a purported majority, squares better with intuition in some circumstances. He also gives an example purporting to show that this new method sometimes corresponds to rational action. We challenge the intuitions and expose a mathematical error in the example. We also offer a model for the local interpretivist semantics. This model puts theoretical local interpretivists on ground as solid as that of Thesis abiders for whom conditionals have truth conditions

A Puzzle about Knowing Conditionals

We present a puzzle about knowledge, probability and conditionals. We show that in certain cases some basic and plausible principles governing our reasoning come into conflict. In particular, we show that there is a simple argument that a person may be in a position to know a conditional the consequent of which has a low probability conditional on its antecedent, contra Adams’ Thesis. We suggest that the puzzle motivates a very strong restriction on the inference of a conditional from a disjunction

First Nations Boil Water Advisories: New Methods and New Approaches for Risk Communication

When issuing drinking water advisories (such as boil water advisories, or BWAs) in First Nations, risk communicators must consider the unique historical, political, social and cultural context. A small number of studies have examined risk communication and message mapping in the First Nations context but First Nations drinking water-specific literature is scarce. A community-based participatory research (CBPR) project was conducted with two First Nations and their tribal council in Saskatchewan. The study examined the applicability of risk communication and message mapping in the First Nations context, with the overall goals of improving local risk communication practices and contributing to a First Nations drinking water risk communication framework. Using the Science in a Circle © model, the research partners developed a four-phase CBPR project, rooted in mutual respect for Indigenous and western science worldviews. Through a series of initial community meetings, the research team determined a novel method would be required to investigate boil water advisory communications using culturally appropriate methods. The Participatory Dot-Mapping Method enabled local leaders, experts and everyday community members to participate in all steps of the research process, including data interpretation. Using coloured dots on a map-like response board, participants from each community used coloured dots to note their main concerns, questions and information needs around BWAs. Current and potential BWA communication tactics were also evaluated. Age-coded dot colours showed differences between life stages or age groups. The results suggest effective risk communication must consider factors unique to each community. These include frequency of advisories and preferred methods of communication (e.g. radio, social media, interpersonal communication). Door-to-door flyers and social media alerts were more popular in one community, with youth and/or Elders showing more interest in other electronic alerts (e.g. text, email). Door-to-door flyers and local radio alerts were more popular in the other community. Like non-Indigenous communities, more research is needed to understand how frequency of boil water advisories should inform their communication, and/or what kinds of messages can improve communications of BWAs. Communities should consider health promotion and education activities around BWAs between advisories. Overall, the Science in a Circle © approach and the Participatory Dot-Mapping Method generated actionable local policy knowledge for First Nations and their agencies

A comprehensive review of wellbore breathing

Wellbore breathing is a common occurrence during drilling operations, but the downhole mechanism and how it manifests itself in surface and subsurface processes, is not well understood. Wellbore breathing events often result in a drilling fluid gain at surface and are misidentified as a kick, resulting in unneeded shut in periods and associated non-productive time (NPT). Further, misidentification of wellbore breathing as underbalance often results in increases in mud weight, which only exacerbates the problem and may cause lost circulation. This work focuses on characterization of the wellbore breathing phenomenon in practical contexts of the pressure, volume, temperature, and time behavior of the components involved in the surface and subsurface system. This was accomplished through the examination of case studies published in literature to develop a comprehensive review of common experiences and incidents, as well as the operational responses to these. Methods for identification, differentiation from kicks and underbalance, mitigation and prevention of wellbore breathing are proposed, in addition to operational procedures for safe continuance of drilling operations. The coupled nature of pressure, temperate, and vii volume, as they pertain to wellbore breathing, are analyzed in detail in order to quantify their effects and how they can inhibit identification of wellbore breathing. This research also proposes adaptation of the hydraulic fracturing pump-in flowback test interpretation developed by Plahn, Nolte, and Miska (1997) for the interpretation of wellbore breathing events and estimation of the minimum horizontal stress. This work presents estimates of the minimum horizontal stress for fractured zones in five wells using PWD data recorded during wellbore breathing events, which was obtained from literature. These estimates were verified qualitatively, when possible, by comparing across multiple connections and with available LOT data.Petroleum and Geosystems Engineerin

Adams Thesis and the Local Interpretation of Conditionals

Adams' Thesis states that the probability of a conditional is the probability of the consequent conditional on the antecedent. S. Kaufmann introduced a rival method, the so-called ``local interpretation'', for calculating the probability of a conditional that, according to a purported majority, squares better with intuition in some circumstances. He also gives an example purporting to show that this new method sometimes corresponds to rational action. We challenge the intuitions and expose a mathematical error in the example. We also offer a model for the local interpretivist semantics. This model puts theoretical local interpretivists on ground as solid as that of Thesis abiders for whom conditionals have truth conditions

COMPARING OUTCOMES OF DRIED BLOOD SPOT AND PLASMA VIRAL LOAD MONITORING FOR HIV TREATMENT IN RESOURCE-LIMITED SETTINGS USING A MARKOV STATE-TRANSITION MODEL

Background and Objective: People living with HIV who are receiving antiretroviral therapy need to be monitored to evaluate treatment failure. Gold standard plasma viral load is logistically difficult in many resource-limited settings; dried blood spot viral load testing may be a more accessible alternative. A Markov state-transition model was created in order to better evaluate the clinical consequences of this alternative. Outcomes were compared to those of plasma viral load, CD4 immunologic criteria, and clinical criteria for treatment failure. Methods: A Markov state-transition model was created with two cohorts of 10,000 sub-Saharan African adults, one ART naïve cohort and one ART experienced cohort. Outcomes of each cohort were simulated over 5 years of follow-up. Outcomes of interest were the number of patients who died or were virologically failing after five years, events of interest were cumulative misclassifications over five years. Results: Dried blood spot viral load testing was 91% as effective as plasma viral load at averting deaths in the ART naïve cohort and 85% as effective in the ART experienced cohort, compared with clinical symptoms monitoring alone. There were more misclassifications with dried blood spot viral load than with plasma viral load. Both dried blood spot and plasma viral load testing lead to fewer deaths and misclassifications than either clinical criteria for treatment failure alone or immunologic criteria. Estimated programmatic costs for plasma viral load and dried blood spot viral load testing were comparable. Conclusions: Dried blood spot viral load is a good alternative to plasma viral load (when the latter is unavailable), with comparable clinical consequences and costs. Viral load should continue to be the treatment monitoring mode of choice, as clinical and immunologic criteria are inadequate for timely and correct determination of treatment failure. Readers: Catherine Sutcliffe, Ph.D. and David Dowdy, MD, Ph.D

Directional Bias

There is almost a consensus among conditional experts that indicative conditionals are not material. Their thought hinges on the idea that if indicative conditionals were material, A → B could be vacuously true when A is false, even if B would be false in a context where A is true. But since this consequence is implausible, the material account is usually regarded as false. It is argued that this point of view is motivated by the grammatical form of conditional sentences and the symbols used to represent their logical form, which misleadingly suggest a one-way inferential direction from A to B. That conditional sentences mislead us into a directionality bias is a phenomenon that is well-documented in the literature about conditional reasoning. It is argued that this directional appearance is deceptive and does not reflect the underlying truth conditions of conditional sentences. This directional bias is responsible for both the unpopularity of the material account of conditionals and some of the main alternative principles and themes in conditional theory, including the Ramsey’s test, the Equation, Adams’ thesis, conditional-assertion and possible world theories. The directional mindset forgets a hard- earned lesson that made classical logic possible in the first place, namely, that grammatical form of sentences can mislead us about its truth conditions. There is a case to be made for a material account of indicative conditionals when we break the domination of words over the human mind

Understanding the Impact of Internal Variability on Estimates of the Transient Climate Response

The transient climate response (TCR) is useful for quantifying the Earth’s short-term (decadal to century timescales) response to an increase in greenhouse gases. The TCR cannot be directly observed, so it is often estimated using the historical temperature record. One important question is the extent to which internal variability confounds these estimates of TCR. To quantify the uncertainty caused by internal variability, we analyze output from a 100-member ensemble of a fully coupled global climate model (Max Planck Institute Earth Science Model, MPI-ESM1.1). Each of the 100 ensemble members has identical historical forcing and model physics but unique initial conditions. The model members consequently evolve differently in time. The TCR estimated from the historical ensemble yields values ranging from 1.34 to 1.9 K, where the spread can be attributed to internal variability alone. We can understand this range using a framework derived from the Earth’s energy balance. A majority of the variability observed in the ensemble estimates of TCR is due to heat transport into the deep oceans, ensemble members that transport more heat to the deep ocean have lower TCRs. Another key factor, is the amount of forcing that is radiated back to space. Together, these two factors explain 71% of the variance in the TCR estimates from the large ensemble. Due to the demonstrated effects of internal variability, an estimate of the TCR from the historical record (a single realization out of many possible climate histories) could deviate significantly from the climate system’s true value

Rethinking the Acceptability and Probability of Indicative Conditionals

The chapter is devoted to the probability and acceptability of indicative conditionals. Focusing on three influential theses, the Equation, Adams’ thesis, and the qualitative version of Adams’ thesis, Sikorski argues that none of them is well supported by the available empirical evidence. In the most controversial case of the Equation, the results of many studies which support it are, at least to some degree, undermined by some recent experimental findings. Sikorski discusses the Ramsey Test, and Lewis’s triviality proof, with special attention dedicated to the popular ways of blocking it. Sikorski concludes that the role of the three theses in future studies of conditionals should be re-thought, and he presents alternative proposals

A Puzzle about Knowing Condtionals

We present a puzzle about knowledge, probability and conditionals. We show that in certain cases some basic and plausible principles governing our reasoning come into conflict. In particular, we show that there is a simple argument that a person may be in a position to know a conditional the consequent of which has a low probability conditional on its antecedent, contra Adams’ Thesis. We suggest that the puzzle motivates a very strong restriction on the inference of a conditional from a disjunction