Truth is I'm not as convinced as Livingston is that Arnold so easily believed in a transcendent God.  Nonetheless, this statement from a notable scholar (not to mention those of Ruth apRoberts) should make us stop short of a strong pronouncement one way or the other.  The eminent scholars are in a quandary on this one (and I am quite reticent to place myself in any category of eminence on this matter), surely their quandary is reason enough for us to look at least for some more qualified statement, and I mean to include by that my own substitute which no doubt also lacked sufficient qualification.

I cannot lay my hands on it just now, but Arnold does say at one point, somewhat defensively, that he believes in God.  I think the problem is that Arnold's beliefs are not really so easily categorizable.  He makes it clear that Spinoza's thoughts appeal to him.  He also clearly states that he believes Spinoza was mis-judged in his time in being declared a heretic.  Part of our problem here might be that today we are so divorced from these older discussions of religion that we only see two alternatives: the belief in a transcendent, historical God, a God with physical attrributes; or no belief in God or anything that even remotely smacks of the metaphysical.  Our only possibility for a middle ground today may well be agnosticism (although, on a personal note, my own beliefs fall into the middle ground, and I would be insulted if anyone ever called me an agnostic, that however is not an argument that should have any relevance for the case with Arnold).  Arnold, I suspect, was quite comfortable dismissing superstition and setting aside metaphysical concerns, while still believeing in God.  The physicality or metaphysicality of that God were not relevant to the virtue they brought to Arnold and to his society.  In his own time he was accused of wanting to eat his cake and take it, too.  But he held out, and to my knowledge mever admitted the doubts that are implicit in agnosticism.

In other words, I think with Arnold, Livingston overstates the case for him, he is not at the center of Protestant thought; Arnold really belongs to a middle ground that is more concerned with the poetry of relgion and its virtues and values for society.  But to call him an agnostic probably places him in an aspect of the middle ground that he would never have felt comfortable inhabiting.  Sorry to offer no quotations.  Let me see what I can find and get back with you.