scholarly journals Fragmentation and Old Evidence

Episteme ◽  
2021 ◽  
pp. 1-26
Author(s):  
Will Fleisher
Keyword(s):  
Inductive Reasoning ◽  
Confirmation Theory ◽  
Bayesian Confirmation Theory ◽  
Bayesian Confirmation ◽  
Scientific Inference ◽  
Formal Framework ◽  
Old Evidence ◽  
Problem Of Old Evidence ◽  
Doxastic States

Abstract Bayesian confirmation theory is our best formal framework for describing inductive reasoning. The problem of old evidence is a particularly difficult one for confirmation theory, because it suggests that this framework fails to account for central and important cases of inductive reasoning and scientific inference. I show that we can appeal to the fragmentation of doxastic states to solve this problem for confirmation theory. This fragmentation solution is independently well-motivated because of the success of fragmentation in solving other problems. I also argue that the fragmentation solution is preferable to other solutions to the problem of old evidence. These other solutions are already committed to something like fragmentation, but suffer from difficulties due to their additional commitments. If these arguments are successful, Bayesian confirmation theory is saved from the problem of old evidence, and the argument for fragmentation is bolstered by its ability to solve yet another problem.

The Problem of Old Evidence

2019 ◽  
pp. 131-154
Author(s):  
Jan Sprenger ◽  
Stephan Hartmann
Keyword(s):  
Bayesian Models ◽  
Scientific Theories ◽  
Confirmation Theory ◽  
Bayesian Confirmation Theory ◽  
Bayesian Confirmation ◽  
New Information ◽  
Novel Theory ◽  
Old Evidence ◽  
Problem Of Old Evidence

In science, phenomena are often unexplained by the available scientific theories. At some point, it may be discovered that a novel theory accounts for this phenomenon—and this seems to confirm the theory because a persistent anomaly is resolved. However, Bayesian confirmation theory—primarily a theory for updating beliefs in the light of learning new information—struggles to describe confirmation by such cases of “old evidence”. We discuss the two main varieties of the Problem of Old Evidence (POE)—the static and the dynamic POE—, criticize existing solutions and develop two novel Bayesian models. They show how the discovery of explanatory and deductive relationships, or the absence of alternative explanations for the phenomenon in question, can confirm a theory. Finally, we assess the overall prospects of Bayesian Confirmation Theory in the light of the POE.

Bayesian belief updating after a replication experiment

2018 ◽  
Vol 41 ◽  
Author(s):  
Alex O. Holcombe ◽  
Samuel J. Gershman
Keyword(s):  
Confirmation Theory ◽  
Bayesian Confirmation Theory ◽  
Belief Updating ◽  
Original Experiment ◽  
Bayesian Confirmation ◽  
Replication Experiment

AbstractZwaan et al. and others discuss the importance of the inevitable differences between a replication experiment and the corresponding original experiment. But these discussions are not informed by a principled, quantitative framework for taking differences into account. Bayesian confirmation theory provides such a framework. It will not entirely solve the problem, but it will lead to new insights.

scholarly journals The Problem of New Evidence: P-Hacking and Pre-Analysis Plans

Diametros ◽  
2020 ◽  
pp. 1-24
Author(s):  
Zoe Hitzig ◽  
Jacob Stegenga
Keyword(s):  
Model Selection ◽  
Policy Option ◽  
Confirmation Theory ◽  
Bayesian Confirmation Theory ◽  
Bayesian Confirmation ◽  
Selection Theory ◽  
New Evidence ◽  
Theory And Model

We provide a novel articulation of the epistemic peril of p-hacking using three resources from philosophy: predictivism, Bayesian confirmation theory, and model selection theory. We defend a nuanced position on p-hacking: p-hacking is sometimes, but not always, epistemically pernicious. Our argument requires a novel understanding of Bayesianism, since a standard criticism of Bayesian confirmation theory is that it cannot represent the influence of biased methods. We then turn to pre-analysis plans, a methodological device used to mitigate p-hacking. Some say that pre-analysis plans are epistemically meritorious while others deny this, and in practice pre-analysis plans are often violated. We resolve this debate with a modest defence of pre-analysis plans. Further, we argue that pre-analysis plans can be epistemically relevant even if the plan is not strictly followed—and suggest that allowing for flexible pre-analysis plans may be the best available policy option.

scholarly journals Coherence and Reduction

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Andrea Giuseppe Ragno
Keyword(s):  
Statistical Mechanics ◽  
Confirmation Theory ◽  
Bayesian Confirmation Theory ◽  
Numerical Examples ◽  
Bayesian Confirmation ◽  
Degree Of Coherence ◽  
Confirmation Measures ◽  
Before And After ◽  
Important Field ◽  
Scientific Reduction

Abstract Synchronic intertheoretic reductions are an important field of research in science. Arguably, the best model able to represent the main relations occurring in this kind of scientific reduction is the Nagelian account of reduction, a model further developed by Schaffner and nowadays known as the generalized version of the Nagel–Schaffner model (GNS). In their article (2010), Dizadji-Bahmani, Frigg, and Hartmann (DFH) specified the two main desiderata of a reduction á la GNS: confirmation and coherence. DFH first and, more rigorously, Tešic (2017) later analyse the confirmatory relation between the reducing and the reduced theory in terms of Bayesian confirmation theory. The purpose of this article is to analyse and compare the degree of coherence between the two theories involved in the GNS before and after the reduction. For this reason, in the first section, I will be looking at the reduction of thermodynamics to statistical mechanics and use it as an example to describe the GNS. In the second section, I will introduce three coherence measures which will then be employed in the comparison. Finally, in the last two sections, I will compare the degrees of coherence between the reducing and the reduced theory before and after the reduction and use a few numerical examples to understand the relation between coherence and confirmation measures.

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