Class discussions about ethical, social, philosophical and other controversial issues frequently result in disagreement. This leaves a problem: has there been any progress? This article introduces and analyses the concept ‘collective epistemic progress’ in order to resolve this problem. The analysis results in four main ways of understanding, guiding and judging collective epistemic progress in the face of seemingly irreconcilable differences. Although it might seem plausible to analyse and judge collective epistemic progress by the increasing vigour of the dialogue community, by how long the conversation is continued, or by how close we have moved towards consensus or the truth, I argue that these fail to provide serviceable analyses or epistemic criteria. Yet, we might instead analyse, understand and judge progress using epistemic criteria such as whether we have: furthered the one distributed process of inquiry or deliberation; and reached mutual understanding; inquiry milestones; or consensus about our procedures.