Necessity, Self Defence, and Numbers
This presentation, which is very a work in progress, aims to examine some of the many puzzles around justifications and proportionality in the criminal law.

Assuming that φing is a pro tanto wrong, to claim that one’s φing is justified is to claim that φing is permissible. But how do we cash this out? By weighing all the relevant reasons for and against φing? It seems plausible to say, against this, that reasons for φing are at least sometimes excluded where justifications are concerned. So the simple weighing model cannot be the whole story. But what reasons for φing are excluded? How do we tell? How should the answer(s) to those questions be applied to (1) self-defence and (2) necessity?

While this is not a presentation on substantive law, we plan to examine aspects of some cases that have taken on a life outside of the legal treatises, such as Dudley and Stephens and Re A. We also try to say something about the strangely under-explored relationship between criminal law justifications and the so-called ‘Trolley Problem’, as well as the related question of when the numbers may count for liability to both necessity and self-defensive harm.