Skepticism and Self-Knowledge

The aim of this project is to explain and to solve the problem of Cartesian skepticism. This problem occurs in contemporary literature as the following argument: If I have knowledge about the external world, then I know that the skeptical hypothesis is false. I do not know that the skeptical hypothesis is false. Therefore, I do not have knowledge about the external world. This argument confronts us with a puzzle: Each of the premises seems highly plausible, but the conclusion seems unacceptable. Therefore, a satisfying solution to the skeptical problem has first to show how we can have knowledge about the external world, and second to explain the striking plausibility of the skeptical scenario. Explaining and solving this skeptical problem is still one of the central epistemological challenges. In contemporary epistemology, there are various competing anti-skeptical strategies discussed, attacked or defended. These anti-skeptical strategies are unsatisfactory for different reasons. Some cannot provide a convincing argument that we can have knowledge about the external world, some cannot explain the plausibility of the skeptical scenario and some fail for both reasons. In this respect, the skeptical problem has still to be regarded as unsolved. In this research project, I will defend the following view: Persons can take two distinct perspectives in reflecting on themselves, an ordinary perspective and a 3rd-person-perspective. Moorean reasoning which means to have knowledge about the external world and to know through inference from this knowledge that the skeptical hypothesis is false, leads to 1st-person-knowledge, which is not one from a 3rd-person-perspective. In the context of Cartesian doubting, we take a 3rd-person-perspetive towards our own mental states and only regard 1st-person- knowledge from a 3rd-person-perspective as adequate. Our capacity of taking 3rd-person-perspectives towards ourselves explains the two intuitions that Cartesian skepticism is strikingly plausible and that Moorean reasoning is inappropriate. However, in the process of ordinary knowledge acquisition we need not take a 3rd-person- perspective. Therefore, we can gain empirical knowledge about the external world and knowledge that the skeptical hypothesis is false through Moorean reasoning in processes of ordinary knowledge acquisition. The skeptical puzzle rests on a confusion of two perspectives of 1st-person-knowledge. Thus I can achieve the two goals of this project: First, to explain how we can have external world knowledge and second to explain the plausibility of the skeptical argument by taking a view which can be labelled as "perspectivism".

This project aimed at explaining the problem of external world skepticism, which is one of key-problems in contemporary epistemology. Explaining the problem of external world skepticism means to explain how we can have knowledge about the external world, given the possibility that all our experiences and beliefs are only deceptions. In this project, I elaborated an innovative account for explaining this problem. This account relies on the view that we take a very specific psychological point of view towards ourselves when doubting the truth of our own experiences and beliefs. This point of view is similar to the ones we take in the contexts of psychotherapeutic self-reflection or in mindful meditation. All these psychological processes share the feature that the reflecting subject takes a detached point of view and, thus, a skeptical point of view towards her own experiences and beliefs. In this project, I argued successfully that skeptical intuitions are essentially based on these specific psychological processes. What is the problem of external world skepticism about? In the contemporary literature, this problem is presented in the form of the following argument: If I have knowledge about the external world, then I know that my experiences and beliefs do not result from deception. I do not know that I am not the victim of such a deception. Therefore, I do not have knowledge about the external world. This argument confronts us with a puzzle: Each of the premises seems plausible, but the conclusion seems unacceptable. Thus, any satisfying solution to the skeptical problem has to accomplish two tasks: First, it has to show how we can have knowledge about the external world, and, second, it must explain the striking plausibility of the skeptical argument. In order to achieve this goal, this research project distinguished two types of cognitive processes, first, processes of ordinary belief formation and ordinary self-reflection, and, second, self-reflection which is based on doubting ones own experiences and beliefs. In this project, I showed in international publications that the skeptical intuitions only concern cognitive processes of the second type. I argue successfully that we have external world knowledge and knowledge that we are not globally deceived in contexts of ordinary self-reflection. However, if we doubt our own experiences and beliefs in philosophical contexts, we perform specific psychological processes of self-reflection that support skeptical intuitions.