We are talking about emergence and emergent properties defined as per the article:
"... emergence occurs when an entity is observed to have properties its parts do not have on their own, properties or behaviors that emerge only when the parts interact in a wider whole"
.
This is also from the article:
"Definitions
This concept of emergence dates from at least the time of Aristotle.[2] The many scientists and philosophers[3] who have written on the concept include John Stuart Mill (Composition of Causes, 1843)[4] and Julian Huxley[5] (1887–1975).
The philosopher G. H. Lewes coined the term
"emergent" in 1875, distinguishing it from the merely
"resultant":
Every resultant is either a sum or a difference of the co-operant forces; their sum, when their directions are the same – their difference, when their directions are contrary. Further, every resultant is clearly traceable in its components, because these are homogeneous and commensurable. It is
otherwise with emergents, when, instead of adding measurable motion to measurable motion, or things of one kind to other individuals of their kind, there is a co-operation of things of unlike kinds. The emergent is
unlike its components insofar as these are
incommensurable, and
it cannot be reduced to their sum or their difference."
This then is the benchmark by which we judge claims of emergence and indeed knowledge of what emergence is.
So it's not enough just to talk about interactions as you seem to be satisfied with but by whether those interactions lead to a
resultant or an
emergent.