“…It is unusual in its sole focus on the mutual support between pairs of elements of the set, as opposed to, say, the coherence of one element with the rest, along the lines ofLewis (1946). For overviews of coherence measures based on mutual support, seeDouven and Mejis (2007),Schippers (2014) andKoscholke (2016). 5 I write "very broadly" because Thagard himself, although his principle E2 c) clearly relies on a concept of "degree of coherence", has stated that he is skeptical regarding the prospects of actually defining such a concept in a precise fashion within his own formal framework.…”