Modeling the Ellsberg Paradox by Argument Strength

TL;DR

This paper introduces a formal measure of argument strength that captures how probability and precision influence argument evaluation, providing a new model for the Ellsberg paradox and aligning with human reasoning.

Contribution

It proposes a novel argument strength measure that explains the Ellsberg paradox and demonstrates psychological plausibility through empirical data.

Findings

The measure predicts human judgments in the Ellsberg task.

Experimental data supports the model's psychological validity.

Qualitative interviews reveal folk concepts of argument strength.

Abstract

We present a formal measure of argument strength, which combines the ideas that conclusions of strong arguments are (i) highly probable and (ii) their uncertainty is relatively precise. Likewise, arguments are weak when their conclusion probability is low or when it is highly imprecise. We show how the proposed measure provides a new model of the Ellsberg paradox. Moreover, we further substantiate the psychological plausibility of our approach by an experiment (N = 60). The data show that the proposed measure predicts human inferences in the original Ellsberg task and in corresponding argument strength tasks. Finally, we report qualitative data taken from structured interviews on folk psychological conceptions on what argument strength means.