The Dynamics of Scientific Knowledge - Mapping Scientific Frontiers: The Quest for Knowledge Visualization - page 12

Fig. 1.1 Conceptual change:
a new conceptual system #2
is replacing an old one #1
but possibly weak link between the two concepts. Removing an existing link can
be seen as a result of a decay of its strength; they no longer have a strong enough
presence in the system to be taken into account. Figure 1.1 illustrates how an old
system #1 is replaced by a new system #2 in this manner. Using this framework,
Thagard identified nine steps to make conceptual changes:
1. Adding a new instance, for example that the blob in the distance is a whale.
2. Adding a new weak rule, for example that whales can be found in the Arctic
Ocean.
3. Adding a strong rule that plays a frequent role in problem solving and explana-
tion, for example that whales eat sardines.
4. Adding a new part-relation, also called decomposition.
5. Adding a new kind-relation, for example that a dolphin is a kind of whale.
6. Adding a new concept, for example narwhale.
7. Collapsing part of a kind-hierarchy, abandoning a previous distinction.
8. Recognizing hierarchies by branch jumping, that is, shifting a concept from one
branch of a hierarchical tree to another.
9. Tree switching, that is, changing the organizing principle of a hierarchical tree.
Branch jumping and tree switching are much rare events associated with
conceptual revolutions. Thagard examined seven scientific revolutions:
1. Copernicus' solar-centric system of the planets replacing the earth-centric theory
of Ptolemy