ABSTRACT
Following the advice of P.M.S. Blackett (in his case concerning large-scale nuclear war), the absence of any actual large-scale terrorist use of weapons of mass destruction means that in order to make any progress in understanding the topic some sort of theoretical approach is necessary (weapons of mass destruction are taken to mean nuclear, radiological, chemical or biological weapons). That is to say the complexities of the world as it is have temporarily to be substituted by simple models that attempt to replicate the essentials of the real world situation (Blackett 1961). As such, the simplifications inherent in the models do not mean that the models are no good for drawing conclusions, but that there is a limit to the weight of interpretation that can be put on the models. Indeed, as a simple example, the comparative rarity with which weapons of mass destruction have been employed in any setting means gaps in information and disagreement between sources regarding even their warlike properties. The models in question are quantitative and qualitative, with only the former bearing much relation to the ‘operations research’ sort of theoretical models Blackett had in mind. The limitations of the qualitative models will normally be self-evident, those of the quantitative models are spelled out in the context of discussion.
