These constraint relationships describe possibilities and so also impossibilities. Given one set of physical values, many other combinations of values are ruled out. It is a way of capturing and expressing the regularities in the world. Counterfactual arguments provide ways of imagining a world in which such regularities either did not exist or had yet to be discovered.
Here, show some of what's known:
Or here, knowing nothing:
These kinds of accounts in the sciences are expressed with constraint relationships. They are not linear path narratives, a series of 'and next' statements: like a novelist's arrangement of events. These are a special kind of story, one that uses a particular type of thinking, not closely related to the causal. This thinking is wholistic and systemic, rather than atomistic and mechanical. The constraint shows possibilities and impossibilities and does not effect a particular outcome.
Energy is perhaps the apogee of this kind of thinking. Notice constraint relationships first in less abstract contexts (level two descriptions) and practise thinking with constraints at that level, preparing for working at level three descriptions with energy.