I am looking for a positive adjective to describe a conversation motivated between objects or ideas of different orders? 'Incommensurate', 'unlikely' et c. come to mind, but is there a positive adjective that appreciates the ingenuity of it?
In short, to institute a creative comparison between apples and oranges is a __________ comparison.
Unexpected.
not expected; unforeseen; surprising: an unexpected pleasure; an unexpected development. (http://www.dictionary.com/browse/unexpected)
You can also choose one of many thesaurus entries at unexpected.
At the heart of Hegel's philosophy is the reconciliation of two contradictory ideas -- thesis and antithesis -- by means of the Hegelian dialectic [Wikipedia], the result being synthesis. In your case, one can think of "apples" as the thesis and "oranges" as the antithesis.
OD:
dialectic: enquiry into metaphysical contradictions and their solutions.
synthesis: (in Hegelian philosophy) the final stage in the process of dialectical reasoning, in which a new idea resolves the conflict between thesis and antithesis [emphasis added]
Your example:
To institute a creative comparison between apples and oranges is a dialectical comparison.
The resulting synthesis is that apples and oranges are both fruits.
These words come to mind as underscoring the capacity of this unlikely comparison to draw out some insight through analogical reasoning or mapping of the source domain (the orange) onto the target domain (the lemon) or vice versa.
Each one of these positive adjectives alludes a contrast between two opposites, states, or realms. That tension between realms evokes the disparity between the domains or 'orders' of your comparison. They highlight the positive nature not only of this comparison, but of distant comparisons in general, which force a shift in perspective.
Words that highlight instead the playfulness of a distant comparison:
