Logical expressions, whether purely logical or not, can be divided into strong and weak ones, just as success-words can; and as I have said, some of them are success-words as well. Examples of strong logical expressions are "entails", "proves", "verifies", "has as a special case". Weak ones include "is consistent with", "supports", "confirms", "is a special case or example of". Logical expressions weaker still include "explains" and "solves the problem of". (Here as elsewhere I generally take verbs as my logical expressions, but of course the cognate noun will be a logical expression too.)
All the above are in an intuitive sense positive logical expressions. Corresponding to them, and for the most part trivially intertranslatable with them, are negative logical expressions. Strong negative ones include "is inconsistent with", "disproves", "refutes", "falsifies", "is a counter-example to", "clashes with". Weak negative expressions include "disconfirms", "is an anomaly for", "poses a problem for", "cannot explain", "fails to predict".
(David Stove, Scientific Irrationalism: Origins of a Postmodern Cult [New Brunswick, NJ, and London: Transaction Publishers, 2001], 57 [italics in original] [book first published as Popper and After: Four Modern Irrationalists in 1982])
