Most approaches to information pay attention only to the 'positive' or constructive side ('presence') of this phenomenon: its composition, construction rules, emergence, effective activity, etc. However, the 'negative' or degrading aspects ('absences', disappearance of activity) are equally important within most biologico-informational processes. In fact, protein degradation can be put on a par with protein synthesis concerning its functionality and sophistication. By taking into account recent integrative discoveries in the molecular biology of the cell (signalling system, cell cycle, apoptosis, protein degradation, enzyme function) a wider approach encompassing both the 'presence' and 'absence' aspects seems possible. The overall dynamics which emerges--involving symmetry breaking and symmetry restoration by means of information processing mechanisms--may be extrapolated to neuronal and socio-economic realms too. Interestingly, the phenomenon of 'absence' can also be pinpointed, at least as a metaphor, within the internal structure of natural numbers.