The concreteness of abstract language: an ancient issue and a new perspective.

This paper addresses the debated issue of abstract language in the framework of embodiment. First, we discuss the notion of abstractness in the light of the Western philosophical thought, with a focus on the English empiricist tradition. Second, we review the most relevant psychological models and neuroscientific empirical findings on abstract language. It turns out that abstract words are not such, because their meaning is "far from experience", but, because of the high complexity of the attached experiential clusters. Finally, we spell out the consequences of this understanding of abstractness in relation to the neural mechanisms subserving abstract language processing. If abstract words, as compared to concrete ones, imply an increasing complexity of the associated experiential clusters, then the processing of abstract language relies on the recruitment of several neural substrates coding for those experiences. We forward that, at the neural level, this complexity is coded by means of three main mechanisms: (1) the recruitment of the motor representations of different biological effectors (abstract meaning as effector-unspecific); (2) the recruitment of different systems, including sensory, motor, and emotional ones (abstract meaning as multi-systemic); (3) the recruitment of neural substrates coding for social contexts and levels of self-relatedness (abstract meaning as dynamic). As compared to the current approaches in the literature on abstract language that combine embodiment with some a-modal aspects, our proposal is fully embodied and rules out additional aspects. Our proposal may spur future empirical research on abstract language in the embodied approach.