15,630 research outputs found
On the Empirical Consequences of the AdS/CFT Duality
We provide an analysis of the empirical consequences of the AdS/CFT duality
with reference to the application of the duality in a fundamental theory,
effective theory and instrumental context. Analysis of the first two contexts
is intended to serve as a guide to the potential empirical and ontological
status of gauge/gravity dualities as descriptions of actual physics at the
Planck scale. The third context is directly connected to the use of AdS/CFT to
describe real quark-gluon plasmas. In the latter context, we find that neither
of the two duals are confirmed by the empirical data.Comment: 15 pages + abstract, references. Submitted to "Beyond Spacetime"
volum
Hawking Radiation and Analogue Experiments: A Bayesian Analysis
We present a Bayesian analysis of the epistemology of analogue experiments
with particular reference to Hawking radiation. First, we prove that such
experiments can be confirmatory in Bayesian terms based upon appeal to
'universality arguments'. Second, we provide a formal model for the scaling
behaviour of the confirmation measure for multiple distinct realisations of the
analogue system and isolate a generic saturation feature. Finally, we
demonstrate that different potential analogue realisations could provide
different levels of confirmation. Our results provide a basis both to formalise
the epistemic value of analogue experiments that have been conducted and to
advise scientists as to the respective epistemic value of future analogue
experiments.Comment: 25 pages, 5 figure
There Is No Pure Empirical Reasoning
The justificatory force of empirical reasoning always depends upon the existence of some synthetic, a priori justification. The reasoner must begin with justified, substantive constraints on both the prior probability of the conclusion and certain conditional probabilities; otherwise, all possible degrees of belief in the conclusion are left open given the premises. Such constraints cannot in general be empirically justified, on pain of infinite regress. Nor does subjective Bayesianism offer a way out for the empiricist. Despite often-cited convergence theorems, subjective Bayesians cannot hold that any empirical hypothesis is ever objectively justified in the relevant sense. Rationalism is thus the only alternative to an implausible skepticism
Epistemological Realism and Onto-Relations
The traditional concept of knowledge is a justified true belief. The bulk of contemporary epistemology has focused primarily on that task of justification. Truth seems to be a quite obvious criterionâdoes the belief in question correspond to reality? My contention is that the aspect of ontology is far too separated from epistemology. This onto-relationship of between reality and beliefs require the epistemic method of epistemological realism. This is not to diminish the task of justification. I will then discuss the role of inference from the onto-relationships of free invention and discovery and whether it is best suited for a foundationalist or coherentist model within a theistic context
On Probability and Cosmology: Inference Beyond Data?
Modern scientific cosmology pushes the boundaries of knowledge and the knowable. This is prompting questions on the nature of scientific knowledge. A central issue is what defines a 'good' model. When addressing global properties of the Universe or its initial state this becomes a particularly pressing issue. How to assess the probability of the Universe as a whole is empirically ambiguous, since we can examine only part of a single realisation of the system under investigation: at some point, data will run out. We review the basics of applying Bayesian statistical explanation to the Universe as a whole. We argue that a conventional Bayesian approach to model inference generally fails in such circumstances, and cannot resolve, e.g., the so-called 'measure problem' in inflationary cosmology. Implicit and non-empirical valuations inevitably enter model assessment in these cases. This undermines the possibility to perform Bayesian model comparison. One must therefore either stay silent, or pursue a more general form of systematic and rational model assessment. We outline a generalised axiological Bayesian model inference framework, based on mathematical lattices. This extends inference based on empirical data (evidence) to additionally consider the properties of model structure (elegance) and model possibility space (beneficence). We propose this as a natural and theoretically well-motivated framework for introducing an explicit, rational approach to theoretical model prejudice and inference beyond data
Policy Advice Derived from Simulation Models
When advising policy we face the fundamental problem that economic processes are uncertain. Consequently, policy can err. In this paper we show how the use of simulation models can reduce policy errors by inferring empirically reliable and meaningful statements about economic processes. We suggest that policy is best based on so-called abductive simulation models, which help to better understand how policy measures can influence economic processes. We show that abductive simulation models use a combination of theoretical and empirical analysis based on different data sets. By way of example we show what policy can learn with the help of abductive simulation models, namely how policy measures can influence the emergence of a regional cluster.Policy Advice, Simulation Models, Uncertainty, Methodology
Policy Advice Derived From Simulation Models
When advising policy we face the fundamental problem that economic processes are connected with uncertainty and thus policy can err. In this paper we show how the use of simulation models can reduce policy errors. We suggest that policy is best based on so-called abductive simulation models, which help to better understand how policy measures can influence economic processes. We show that abductive simulation models use a combination of theoretical and empirical analysis based on different data sets. This helps inferring empirically reliable and meaningful statements about how policy measures influence economic processes. By way of example we show how research subsidies by the government influence the likelihood that a regional cluster emerges.Policy Advice, Simulation Models, Uncertainty, Methodology
The Two Methods of Economics
A Teoria EconĂŽmica Emprega Dois MĂ©todos: o MĂ©todo HipotĂ©tico-Dedutivo, Utilizado Principalmente Pelos Economistas NeoclĂĄssicos, e o MĂ©todo HistĂłrico-Dedutivo, Adotado Pelos Economistas ClĂĄssicos e Keynesianos. Ambos sĂŁo LegĂtimos, Mas, Desde que a Economia Ă© Substantiva, nĂŁo uma CiĂȘncia MetodolĂłgica, Onde o Objeto Ă© o Sistema EconĂŽmico, o MĂ©todo HistĂłrico-Dedutivo Ă© o Mais Apropriado. o MĂ©todo HipotĂ©tico-Dedutivo Permite que o Economista Desenvolva Ferramentas para Analisar o Sistema EconĂŽmico, Mas Falha ao Analisar o Sistema como um Todo. em Contrapartida, o MĂ©todo HistĂłrico-Dedutivo Parte da Observação EmpĂrica da Realidade e da Busca por Regularidades e TendĂȘncias. Ă© um MĂ©todo EmpĂrico, Apropriado para as CiĂȘncias Substantivas que Tratam de Sistemas Abertos, como Ă© o Caso da Economia.
On the Empirical Consequences of the AdS/CFT Duality
We provide an analysis of the empirical consequences of the AdS/CFT duality with reference to the application of the duality in a fundamental theory, effective theory and instrumental context. Analysis of the first two contexts is intended to serve as a guide to the potential empirical and ontological status of gauge/gravity dualities as descriptions of actual physics at the Planck scale. The third context is directly connected to the use of AdS/CFT to describe real quark-gluon plasmas. In the latter context, we find that neither of the two duals are confirmed by the empirical data
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