[masswerk]

Simplicity is often a matter of perspective, a function of a certain perception of a complex subject and the set of expectations that go with this perception. There is no absolute in analysis and in modelling synthetic propositions from the atoms used by the particular analysis.

(E.g., we may analyse and model an action in terms of verb-noun or of noun-verb, with major differences in what may be perceived as "simple" in the respective model.)

[astrobe_]

> Simplicity is often a matter of perspective

Complexity was formally defined by Kolmogorov, using with Turing machines even. Hence, Simplicity is also objectively defined.

[masswerk]

Referring to the above example of verb-noun vs noun-verb grammar: take for example the infinitive verb form. With the former (verb-noun) it's just the verb devoid of any context, simplicity in its purest, which is also, why and how it's listed in a lexicon. Looking at this from the noun-verb perspective, you've to construct a hypothetical minimal viable object, which will be also – as you want to keep things simple – the object every other object inherits from, the greatest common denominator of any objects that may appear in your system. By this, you arrived at the most crucial architectural questions of your system and its reach and purpose. While it's still about simple things, neither the task nor the definitions derived from the process will be simple at all. Nor is there a universally accepted simple answer, as a plurality of object oriented approaches may testify for. The question is on an entirely different scale and level for the two approaches. On the other hand, for a verb-noun approach, similar may appear for anything involving relations, which are already well defined in an object oriented approach. And, as you've arrived at these simple fundamentals of simplicity in your system, what may be simple or not in your systems will depend on the implicit contracts included in these definitions and how well they stand the test of time and varying use and purpose.