“There is a saying of the good Rutherford, difficult for us to acquiesce in, but true I think in principle, to this effect: The permission of sin is adorable, the actual fact of sin is abominable. As to the permissio, there would certainly have been no display of some of the Divine attributes had sin not been. They would have been conserved for ever in the depths of the adorable Godhead. The reality of sovereign love toward rebellious children could not have been displayed without a fall. This is the basis of a modified optimism. … In a certain sense I am a tremendous free-willer. My predestination is all free will” (Colloquia peripatetica: (deep-sea soundings): being notes of conversations by the late John Duncan L.L.D. with the Rev. William Angus Knight). SOURCE
In light of the Calvinist belief in a partially-sovereign god and “efficacious permission,” this is a money quote:
“My predestination is all free will.”
For the VAST MAJORITY who call themselves “Calvinist,” I don’t doubt it for a moment.