À primeira vista, Plotino e Santo Tomás assumem posições contrastantes, no que tange à criação: a necessidade ressaltada por Plotino é negada na concepção cristã de criação. Para não incidirmos em erro, mister se faz retomar o sentido do termo necessidade (ananke) empregado pelo licopolitano. Três são os aspectos a serem considerados: primeiro, necessidade, em Plotino, significa coação externa. Ora, nada há, acima ou fora do Uno, que possa obrigá-lo a fazer algo ou impedi-lo de fazer. Em segundo lugar, a necessidade no Uno não se distingue da vontade; do contrário, ele não seria simples. Logo, em agindo, age voluntariamente. Em terceiro lugar, o Uno não há mister das coisas por ele produzidas. Logo, a ananke significa a difusão de si sem inveja.
Em razão do que foi exposto, conclui-se que, entendendo necessidade como coação ab extra, nem ao Uno de Plotino nem ao Deus cristão pode ser aplicado o termo. [Ullmann]
But why does the existence of the Principle of Good necessarily comport the existence of a Principle of Evil? Is it because the All necessarily comports the existence of Matter? Yes: for necessarily this All is made up of contraries: it could not exist if Matter did not. The Nature of this Kosmos is, therefore, a blend; it is blended from the Intellectual-Principle and Necessity: what comes into it from God is good; evil is from the Ancient Kind which, we read, is the underlying Matter not yet brought to order by the Ideal-Form. Enneads: I. VIII. 7
This brings us to the Spindle-destiny, spun according to the ancients by the Fates. To Plato the Spindle represents the co-operation of the moving and the stable elements of the kosmic circuit: the Fates with Necessity, Mother of the Fates, manipulate it and spin at the birth of every being, so that all comes into existence through Necessity. Eneada-II-3-9|Enneads: II III.9
According to Plato, lots and choice play a part [in the determination of human conditions] before the Spindle of Necessity is turned; that once done, only the Spindle-destiny is valid; it fixes the chosen conditions irretrievably since the elected guardian-spirit becomes accessory to their accomplishment. Enneads: II III. 15
But it is the theory of the most rigid and universal Necessity: all the causative forces enter into the system, and so every several phenomenon rises necessarily; where nothing escapes Destiny, nothing has power to check or to change. Such forces beating upon us, as it were, from one general cause leave us no resource but to go where they drive. All our ideas will be determined by a chain of previous causes; our doings will be determined by those ideas; personal action becomes a mere word. That we are the agents does not save our freedom when our action is prescribed by those causes; we have precisely what belongs to everything that lives, to infants guided by blind impulses, to lunatics; all these act; why, even fire acts; there is act in everything that follows the plan of its being, servilely. Enneads: III I. 7