Introduction: addressing the hard problem.

Abstract

This special issue is concerned with what I take to be the leading in the biological sciences today. Indeed a case could be made that it is the leading in science in general. To put the at its most succinct: How exactly do neurobiological processes in the brain cause consciousness? This is sometimes called \the hard problem to suggest that it is a di®erent in kind from such other neurobiological problems as for example, how does the re°ex arc work, what is the exact role of neurotransmitters in action potentials? I will now explain the in a way that will enable us to expand its formulation to include more aspects. First we will have to answer the question, what is consciousness? Consciousness is sometimes said to be hard to de ne but I think if we are just talking about a common sense de nition that identi es the target of the discussion and not a scienti c de nition of the sort that typically comes at the end of the investigation, then consciousness is not hard to de ne. Here is the de nition. By \consciousness we mean all of our states of feeling or sentience or awareness. These typically begin in the morning when we wake from a dreamless sleep and they go on all day until we once again fall asleep, or otherwise become unconscious. On this de nition dreams are a form of consciousness. Consciousness so de ned only exists insofar as experienced by human or animal subjects and we can say therefore it has a rst person or subjective ontology (where \ontology just means the mode of existence). What exactly is the relation between consciousness so de ned and the brain? Well opinions di®er about that and indeed it is the traditional mind–body problem. But I think in general outline, we know enough about how the world works to state the general features of the answer to the question. All of our conscious states without exception are caused by lower level neuronal processes in the brain. The textbooks typically assume that the neuron is the basic functional unit but for all we know it may be something higher than the level of individual neurons, such as whole maps or Journal of Integrative Neuroscience, Vol. 13, No. 2 (2014) vii–xi °c Imperial College Press DOI: 10.1142/S0219635214020014