Abstract

The scientific study of consciousness with its cornerstone of searching the neural correlates of consciousness constitutes an exciting and lively area of research. Yet, the empirical study of consciousness is surrounded by a host of philosophical challenges some of which are not new, while others have arisen and been elaborated over the last decades. The terminology can sometimes be confusing, causing misunderstandings how the challenges relate to each other. This paper provides an overview of several much-discussed philosophical problems of consciousness, offering a way of arranging them and some thoughts about how they relate. Most labels are taken from the literature so that there is a progression from the “easy” via the “hard” to the “harder” problem(s), and some labels are made up, like the “hardest” problem. For reasons of space, there is not detailed discussion of the possible solutions to these problems even though some problems have been formulated in response to others. For example, the “real” problem approach and the “illusion” or “meta” problems can be read partly as responses to the “hard” problem.