Full Idea
The strength of the claim that p is 'absolutely necessary' derives from the fact that in its expression as a universally quantified counterfactual ('everything will necessitate p'), the quantifier ranges over all propositions whatever.
Gist of Idea
'Absolute necessity' is when there is no restriction on the things which necessitate p
Source
Bob Hale (Necessary Beings [2013], 04.1)
Book Reference
Hale,Bob: 'Necessary Beings' [OUP 2013], p.99
A Reaction
Other philosophers don't seem to use the term 'absolute necessity', but it seems a useful concept, in contrast to conditional or local necessities. You can't buy chocolate on the sun.
Related Idea
Idea 15291 There is 'absolute' necessity (implied by all propositions) and 'relative' necessity (from what is given) [Harré/Madden]