Counterfactual Dependencies Kasper Højbjerg Christensen Abstract: This thesis is concerned with developing an adequate semantics for counterfactual conditionals. A counterfactual conditional is standardly taken to be an expression of the form ‘if it had been the case that ϕ, it would have been the case that ψ’, where ϕ and ψ are sentences and ϕ furthermore expresses something false. Now since expressions of this form are not truth-functional in the standard sense, the task of coming up with an adequate semantics for them has proven to be a somewhat difficult affair. We will present some theories of counterfactuals and discuss the problems that these have. Many of these theories agree that to evaluate a counterfactual we need prior knowledge of certain relationships in the world. We agree on this point, but we will redefine what these relations are; namely generation relations where we say that X and Y are in this relation when X will bring about Y , while remaining silent on whether Y will obtain when X does not. We incorporate this into a dynamic setting where the meaning of a sentence is an operation on the cognitive state of an agent. We also draw a distinction between a counterfactual being true in an absolute sense and a counterfactual being acceptable by an agent. Throughout the thesis we will concern ourselves mostly with the latter notion and propose that if one believes in such a thing as the truth-value of a counterfactual, then this is to be defined as acceptability by a certain idealized agent.