As Systems of Systems proliferate in our increasingly connected world, so Systems of Systems Engineering is likely to become the predominant concern of INCOSE. There is merit therefore in taking a fresh look at how we define and categorise the subject, which has grown considerably since it was first identified in the 1990's. This paper is based on observations on the field of SoSE as it is now practised, with an attempt to re‐address how it might be codified in a logical manner. Paradoxes and difficulties remain, and others are encouraged to take up the continuing challenge of rationalising the underpinnings of this key subject.