In other words, Arminians are just stupid Christians who refuse to mature intellectually. Here is the quote:
Calvinism is the natural theology written on the heart of the new man in Christ, whereas Arminianism is an intellectual sin of infirmity, natural only in the sense in which all such sins are natural, even to the regenerate. Calvinistic thinking is the Christian being himself on the intellectual level; Arminian thinking is the Christian failing to be himself through the weakness of the flesh. Calvinism is what the Christian church has always held and taught when its mind has not been distracted by controversy and false traditions from attending to what Scripture actually says. (taken from: J.I. Packer and Arminianism)
Roger Olson rightly concludes, “So, to him, Arminianism is sin.” And we are told that Calvinism is supposed to promote humility in its adherents!? However, it seems to me, again and again, that Calvinism’s “natural” effect is to promote pride and smugness in those who come to embrace it. And of course, Packer’s last sentence is demonstrably Historically false (see here for several posts on the subject). What is truly sad and alarming is that this comes not from misguided internet Neo-Reformed types, but from a mainstream Calvinist scholar.