Making counterfactual assumptions Frank Veltman Abstract: This paper provides an update semantics for counterfactual conditionals. It does so by giving a dynamic twist to the `Premise Semantics' for counterfactuals developed in the late seventies. It also offers an alternative solution to the problems with naive Premise Semantics discussed by Angelika Kratzer in `Lumps of Thought. Such an alternative is called for given the triviality results presented in Kanazawa et.al (to appear). Kanazawa, M., S. Kaufmann, and S. Peters,"Conditionals in Possible Worlds: Times Three", Journal of Semantics, 2005, to appear. Kratzer, A.,"An investigation of the lumps of thought",Linguistics and Philosophy,1989,3-27. Keywords: Update semantics; conditionals; counterfactuals