Simpleposie has a whole series of art history-minded questions up right now, including this one: "What would you consider to be the value of developing an historical imagination?" Having raised the idea, I suppose I should attempt an answer. First, I have to admit that my use of the phrase was more than a little glib in that all I know about Owen Barfield I learned from Howard Nemerov poems, and I've never read too deeply in Collingwood, either. So the particulars of their thinking don't necessarily concern me. What I suppose I meant was that studying the art of the past gives one a very direct apprehension that whoever made and first looked at these things was, while recognizable to us in all sorts of ways, going about things very differently than we do. What those differences are, what's within the implied scope of understanding of those past persons, what was possible or seemingly natural for them and what was not, what became possible at a different moment - these and a host of other questions come to mind. By seeing and appreciating the differentness of the past, and then to imaginatively attempt to mentally reconstruct it, is something bound up in all sorts of historical practice, but art history lays it out more plainly than most if only because it deals with what is seen.
What's the value of all this? In one sense, not much, if you're not planning to pursue further study in the field, or in a similar one. The usual bromides in favor of historical knowledge (doomed to repeat it, etc.) don't really apply. But developing one's historical sense and imagination does help when trying to understand, as one gets called upon to do, different people in the present. It fosters the qualities of judgement and tact, forbearance balanced by the ability to measure, not to mention an appreciation for the breadth and diversity of human experience, that are valuable in all sorts of ways. Not that it always works out, but nevertheless.
Too much earnestness! Time for some garage rock .mp3s, or if none are handy, Ravenna mosaics. Come on and ride on that fantastic journey. To summon up all of my imaginative power, let me say: cool.