The Irrelevance of the Risk-Uncertainty Distinction

Abstract

Precautionary Principles are often said to be appropriate for decision-making in contexts of uncertainty such as climate policy. Contexts of uncertainty are contrasted to contexts of risk depending on whether we have probabilities or not. Against this view, I argue that the risk-uncertainty distinction is practically irrelevant. I start by noting that the history of the distinction between risk and uncertainty is more varied than is sometimes assumed. In order to examine the distinction, I unpack the idea of having probabilities, in particular by distinguishing three interpretations of probability: objective, epistemic, and subjective probability. I then claim that if we are concerned with whether we have probabilities at all-regardless of how low their epistemic credentials are-then we almost always have probabilities for policy-making. The reason is that subjective and epistemic probability are the relevant interpretations of probability and we almost always have subjective and epistemic probabilities. In contrast, if we are only concerned with probabilities that have sufficiently high epistemic credentials, then we obviously do not always have probabilities. Climate policy, for example, would then be a case of decision-making under uncertainty. But, so I argue, we should not dismiss probabilities with low epistemic credentials. Rather, when they are the best available probabilities our decision principles should make use of them. And, since they are almost always available, the risk-uncertainty distinction remains irrelevant.

Climate Uncertainty, Real Possibilities and the Precautionary Principle

“…This evidence, in turn, could be described in terms of evidential probability. 6 Hence, in situations where we can identify real possibilities, evidential probabilities cannot be entirely absent (Roser, 2017).…”

“…That is, if we have at least some evidence that X will occur, then we are also in a position to ascribe an evidential probability to X, although the epistemic credentials of this ascription may be rather low, depending on the quality of the evidence on which the statement rests. Moreover, as Roser (2017) argues, in principle there are myriad evidential grounds on which probabilities can be ascribed. For instance, in the context of climate change, the evidence of decision-makers ranges from things such as background knowledge about the stability of natural systems under human influence (…), the tone of voice with which scientists speak about the dangers of climate change, the track record of science in forecasting long-term trends, the probabilities that scientists give in IPCC reports which in turn are based on empirical data and the general body of natural science, etc.…”

The Idea of Precaution: Ethical Requirements for the Regulation of New Biotechnologies in the Environmental Field

“… 15 Others deny the relevance of the distinction between uncertainty and risk by arguing that, practically, uncertainty is a case of risk (cf. Roser, 2017). …”

Security and Distribution, or Should You Care about Merely Possible Losses?

“…One more tangential point about the paper which may be helpful for many environmental philosophers. While Herington is absolutely right that there is significant difficulty in determining the probabilities of various harms due to climate change, especially when downscaled regionally or locally, and he is also right that this does not preclude doing our best to assess probabilities given our epistemic situation (Roser, 2017), he seems to mischaracterize something about IPCC language regarding risk. Casual readers of the Summaries for Policymakers (SPM) might also be subject to the same mistake.…”