Modality
From Wikipedia. Modality is an important concept for OSE, since OSE lives in the world of possibility - not actuality. An important distinction lies in identifying whether one is a possibilist or an actualist - similar to a realist vs idealist.
Modality concerns the concepts of possibility, actuality and necessity. In contemporary discourse, these concepts are often defined in terms of possible worlds.[10] A possible world is a complete way how things could have been.[30] The actual world is one possible world among others: things could have been different than they actually are. A proposition is possibly true if there is at least one possible world in which it is true; it is necessarily true if it is true in all possible worlds.[31] Actualists and possibilists disagree on the ontological status of possible worlds.[10] Actualists hold that reality is at its core actual and that possible worlds should be understood in terms of actual entities, for example, as fictions or as sets of sentences.[32] Possibilists, on the other hand, assign to possible worlds the same fundamental ontological status as to the actual world. This is a form of modal realism, holding that reality has irreducibly modal features.[32] Another important issue in this field concerns the distinction between contingent and necessary beings.[10] Contingent beings are beings whose existence is possible but not necessary. Necessary beings, on the other hand, could not have failed to exist.[33][34] It has been suggested that this distinction is the highest division of being.[10][35]