 Whereas metaphors originally were a means of illustrating the reality of an issue, giving form to understanding, they were later to tend towards a separate existence, in the sciences as elsewhere.This phenomenon may range from the attempt to fully explicate the metaphor while losing sight of its illustrative function, to the experience of becoming immersed in metaphors influencing the seeming logicality of conclusions.The idea of 'absolute metaphors' turns out to be of decisive importance for the ideas of a culture, such as the metaphor of light as truth in Neo-Platonism, to be found in the hermeneutics of Martin Heidegger and Hans-Georg Gadamer.