For a conjugate likelihood-prior model in the one-parameter exponential family of distributions, we show that, by letting the parameters of the conjugate exponential prior vary in suitable sets, it is possible to define a set of conjugate priors M that guarantees prior near-ignorance without producing vacuous inferences. This result is obtained following both a behavioural and a sensitivity ana...

A central question in our understanding of the physical world is how our knowledge of the whole relates to our knowledge of the individual parts. One aspect of this question is the following: to what extent does ignorance about a whole preclude knowledge of at least one of its parts? Relying purely on classical intuition, one would certainly be inclined to conjecture that a strong ignorance of ...

Previous studies of ignorance-driven decision-making have either analyzed when ignorance should prove advantageous on theoretical grounds, or else they have examined whether human behavior is consistent with an ignorance driven inference strategy (e.g., the recognition heuristic). The current study merges these research goals by examining whether – under conditions where ignorance driven infere...

When prior probabilities are given as data, there is generally little objection to the use of the Bayes formula or Bayesian networks. On the other hand, when prior probabilities are lacking, Bayesians have the tendency to ignore their ignorance and to make the priors up out of thin air. This leads to decisions in situations where gathering more information would be more appropriate. This paper ...

One of the greatest challenges facing humanity is ignorance—the lack of reliable information about and knowledge of the natural world we live in. Those who have studied the workings of the universe realize that the physical laws that govern our planet are the same as those that govern activities throughout the universe. This generalization certainly applies to the laws of physics, chemistry, an...

This paper studies the consequences of alternative ways of representing uncertainty about a law of motion in a version of a classic macroeconomic targetting problem of Milton Friedman (1953). We study both “unstructured uncertainty” – ignorance of the conditional distribution of the target next period as a function of states and controls – and more “structured uncertainty” – ignorance of the pr...

The representation of ignorance is a long standing challenge for researchers in probability and decision theory. During the past decade, Artiicial Intelligence researchers have developed a class of reasoning systems, called Truth Maintenance Systems, which are able to reason on the basis of incomplete information. In this paper we will describe a new method for dealing with partially speciied p...

I discuss the historical and conceptual roots of reasoning about the parameters of fundamental physics and cosmology based on selection effects. I argue concretely that such reasoning can and should be combined with arguments based on symmetry and dynamics; it supplements them, but does not replace them. * Summary talk at " Expectations of a Final Theory " , Trinity College, Cambridge, Septembe...

Inquisitive attitude verbs like wonder do not just imply that their subject does not know the answer to the embedded question, but a stronger form of ignorance, which has been called distributive ignorance (Roelofsen and Uegaki, 2016). Similarly, if an epistemic attitude verb like believe takes a disjunctive complement, it implies that its subject considers all disjuncts possible. We present tw...

In this paper, I respond to Pierre Le Morvan’s critique of my thesis that ignorance is lack of true belief rather than absence of knowledge. I argue that the distinction between dispositional and non-dispositional accounts of belief, as I made it in a previous paper, is correct as it stands. Also, I criticize the viability and the importance of Le Morvan’s distinction between propositional and ...