Higher seminar in Theoretical Philosophy: Henrik Thorén "What is a scenario? (And what are they good for?)"

What is a scenario? (And what are they good for?)

Scenarios are becoming increasingly important within a range of scientific disciplines as well as when scientists want to communicate risk and uncertainty to policy makers. For instance, in both the assessment and special reports of the IPCC scenario frameworks often make out a backbone in structuring the scientific insights and crucial uncertainties. Another recent example from the Swedish context is the provided by the Public Health Authority of Sweden during the pandemic. For most of the pandemic they published, on a weekly basis, three scenarios, that reflected primarily uncertainties about the infectivity of the virus looking ahead.

Yet scenarios appear to be a constant source for confusion among end-users, and no wonder. It can be difficult to grasp the difference between scenarios and (to mention a few) models, predictions, projections, narratives, storylines, simulations, forecasts, models, and pathways. This is somewhat ironic given the communicate purposes that underpin the use of scenarios in the first place.

This talk is an attempt to bring some structure to the scenario concept looking in particular at the use of the concept in the context of the IPCC and epidemiological scenarios developed and deployed during the pandemic. Departing from these case studies I will argue that scenarios are fundamentally about uncertainty domestication, that is the management and structuring of uncertainty and suggest we can think of scenarios as being at least three idealized (and in practice often overlapping) types; probabilistic scenarios, possibilistic scenarios, and axiological (or normative) scenarios. Towards the end of the talk, I will turn to the topic of values-ladenness in scenario-design and outline both risks and opportunities with scenarios when used at the science-policy interface.