  The paper proposes a text-mining based analytical framework aiming at the
cognitive organization of complex scientific discourses. The approach is based
on models recently developed in science mapping, being a generalization of the
so-called Science Overlay Mapping methodology, referred to as Topic Overlay
Mapping (TOM). It is shown that via applications of TOM in visualization,
document clustering, time series analysis etc. the in-depth exploration and
even the measurement of cognitive complexity and its dynamics is feasible for
scientific domains. As a use case, an empirical study is presented into the
discovery of a long-standing complex, interdisciplinary discourse, the debate
on the species concept in biosystematics.
