Abstract Vagueness is a topic much studied by linguists, computer scientists and logicians. This talk, which would be suitable for a broad audience of people interested in science, will start demonstrating the generality of the phenomenon of vagueness, in science as well as in daily life. I will show that vagueness cannot be "reasoned away" (as has recently been attempted) and conclude that vagueness is, in some ways, like Original Sin: a stain that can be diminished but never removed. I will then argue that probabilistic approaches to vagueness have the future, but that this paradigm shift comes at a price. For if vagueness is taken seriously in this way then life gets complicated, because we will be expelled from Boole's Paradise, where every statement is either true or false. This talk is related to the book "Not Exactly: in Praise of Vagueness”, which has appeared with Oxford University Press earlier this year. Web site accompanying Not Exactly: in Praise of Vagueness by Kees van Deemter, Oxford University Press - http://www.csd.abdn.ac.uk/%7Ekvdeemte/NotExactly Short biography Dr van Deemter is an academic working in Computational Linguistics, the area of Artificial Intelligence where Computer Science meets Linguistics. His main areas of expertise are Computational Semantics and Natural Language Generation. Kees takes a lively interest in logical and philosophical issues arising in these areas. He started his career at Philips Research Laboratories in Eindhoven, at the Institute for Perception Research. During his time with Philips (1984-1997), he did a PhD at the University of Amsterdam (1991) and was a postdoctoral researcher at Stanford University. He has worked as a Principal Research Fellow at the Information Technology Research Institute (ITRI) in Brighton and, from 2004, as a Reader in Computing Science at the University of Aberdeen.