  On the other hand, and this is what expands the reference potential of a concept, there are various descriptions available, which speakers might use to fix the reference of the term “gene”. Furthermore, there are several causal trajectories by which various groups of experts are connected to situations where the term was introduced by something akin to ostension. Finally, there are always new situations in which researchers refer by ostension in direct interaction with genes, possibly based on new kinds of experiments. Conceptual change for Kitcher is thus constituted by changes in the reference potential of a concept, in this case, in the ways tokens of the term “gene” refer to genes (if they refer at all).