perhaps one's term 'cloud' denotes a vague object precisely. This strategy has been poorly received, in part due to Gareth Evans's short paper "Can There Be Vague Objects?" (1978). Evans's argument appears to show that there can be no vague identities (e.g. "Princeton = Princeton Borough"), but as Lewis (1988) makes clear, Evans takes for granted that there are in fact vague identities, and that any proof to the contrary cannot be right. Since the proof Evans produces relies on the assumption that terms precisely denote vague objects, the implication is that the assumption is false, and so the vague-objects view is wrong. Still by, for instance, proposing alternative deduction rules involving Leibniz's law or other rules for validity some philosophers are willing to defend ontological vagueness as some kind of metaphysical phenomenon. One has, for example, Peter van Inwagen (1990), Trenton Merricks and Terence Parsons (2000). Legal principle In the common law system, vagueness is a possible legal defence against by-laws and other regulations. The legal principle is that delegated power cannot be used more broadly than the delegator intended. Therefore, a regulation may not be so vague as to regulate areas beyond what the law allows. Any such regulation would be "void for vagueness" and unenforceable. This principle is sometimes used to strike down municipal by-laws that forbid "explicit" or "objectionable" contents from being sold in a certain city; courts often find such expressions to be too vague, giving municipal inspectors discretion beyond what the law allows. In the US this is known as the vagueness doctrine and in Europe as the principle of legal certainty. See also Essentially contested concept Fuzzy concept Unconstitutional vagueness Obfuscation Relevance Understanding Imprecise language References Further reading Deemter, Kees van. Not Exactly: In Praise of Vagueness (Oxford University Press; 368 pages; 2010). Considers vagueness as both a useful and unavoidable aspect of realms from everyday life to computing. The editors' long introduction gives a clear and very useful overview of theories of vagueness, and they collect many classic papers on the subject. Keefe, R. 2000. Vagueness. Cambridge: Cambridge University Press. Technicalities are kept to a minimum to favour a clear account, extremely useful to both students and researchers. Ronzitti, Giuseppina (ed.), Vagueness: A Guide. Logic, Epistemology, and the Unity of Science, Springer, Dordrecht, 2011. External links Concepts in the philosophy of language Semantics Fuzzy logic Ambiguity Concepts in logic Homonymy Formal semantics