ABSTRACT
Leaving aside the community/individual for the present, we explain what we mean by letness by examining metaphors. Metaphors are a visible manifestation of letness, so an understanding of how metaphors work can help in understanding semiotics. We describe some general features of metaphors: how they manifest letness, the part they play in everyday life, and their importance in scientific theory. Metaphors are intended to make the abstract less abstract. But sometimes serious category mistakes occur: abstract constructs like intention or motivation are reified (made tangible), and researched ‘scientifically’, as if they had the same quantifiable properties as solid objects. This can have serious consequences if results are translated into action. We provide an extended example: the ubiquitous metaphor ‘surface/deep’ and how it is used by physical and social scientists to explain visible phenomena such as planetary movement and human behaviour. We examine the metaphor’s success in explaining and predicting scientific phenomena and its failure in explaining behavioural phenomena, giving examples from physics, linguistics, psychology, and behaviour theory. The advent of computers has firmed the behavioural science view that something deep in the brain controls the surface phenomenon of behaviour. Computers use algorithms and inputs and outputs, and behavioural science widely assumes that people do too.
