Chen Liu (LSE) - 2024-25 Students
C.Liu84@lse.ac.uk

Norms Governing Credence Updates after Awareness Growth

1 Research Question and Context

A significant part of the Bayesian project is to explore norms governing credence updates in light of new information. Traditional Bayesianism mainly focuses on a particular type of new information, i.e., some proposition that we had previously considered is indeed true. The norm governing credence updates in light of this type of information is known as (Jeffery) Conditionalization. Bayesian epistemologists have done a lot of work around proving and developing this norm (e.g., Greaves and Wallace (2006)). However, learning that a proposition is true does not exhaust all possible types of information we may receive. In particular, we may become better informed by entertaining a proposition that we have not considered before and to which we do not assign a credence. This phenomenon is dubbed as awareness growth in the literature(Steele and Stef´ansson 2021a). Sadly, traditional Bayesianism provides no guidance when we grow in awareness. Since Bayesianism aims to provide a complete theory of credence updates in light of new information and awareness growth is a significant way in which we can be better informed, Bayesian epistemologists should accommodate awareness growth within the Bayesian framework.

2 Aims and Objectives

My research aim is to extend Bayesianism to cases of awareness growth and give a systematic answer to the question ‘How should we update our credences in light of awareness growth?’. This question can be broken down into the following sub-questions:

– How should we model awareness growth within the framework of Bayesianism

– How should we assign credences to propositions of which we are newly aware?

– How should we revise our credences in other propositions that we have considered before in light of awareness growth?

3 Its Potential Applications and Benefits

In response to climate change, many decisions need to be made: national governments need to make climate policies and individuals need to choose their lifestyle. So climate decision-making has emerged in recent decades as an area of research and practice.

Climate decision-making strongly relies on our knowledge of the world. Which scientific theories about climate change are more probable to be correct largely influences what climate policies governments should adopt. So, many philosophers work on how to update our confidence in different scientific theories in light of new evidence. But in addition to obtaining new evidence, there is another significant way in which our confidence in different theories is affected. This is: to formulate new scientific theories. In the history of climate science, new theories about climate change have been consistently formulated. How much confidence should we have in those new theories? How should the formulation of these new theories affect our confidence in the old ones. My proposed research provides answers to these questions.

Primary Supervisor: Professor Richard Bradley