Anneli Jefferson

Slippery slope arguments are frequently dismissed as fallacious or weak arguments but are nevertheless commonly used in political and bioethical debates. This paper gives an overview of different variants of the argument commonly found in the literature and addresses their argumentative strength and the interrelations between them. The most common variant, the empirical slippery slope argument, predicts that if we do A, at some point the highly undesirable B will follow. I discuss both the question which factors affect likelihood of slippage and the relation between the strength of the prediction and the justificatory power of the argument.

Here we consider the nature of unrealistic optimism and other related positive illusions. We are interested in whether cognitive states that are unrealistically optimistic are belief states, whether they are false, and whether they are epistemically irrational. We also ask to what extent unrealistically optimistic cognitive states are fixed. Based on the classic and recent empirical literature on unrealistic optimism, we offer some preliminary answers to these questions, thereby laying the foundations for answering further questions about unrealistic optimism, such as whether it has biological, psychological, or epistemic benefits.