I recently ran into a college professor--someone I very much respect--who was of the opinion that rhetoric does not include the visible. I suppose it all depends on how you define certain key terms, one of them being rhetoric. I adhere to the classical definition; rhetoric is the art of persuasion. I would also go so far as to say that what I study (and what this blog explores) is the rhetorical nature of various texts, with "texts" loosely defined, perhaps, as anything with an author. (I think that definition of texts to be a little more problematic, but I'll work on it.) This would include visible artifacts. I'll use just such an artifact as an example, because I think visible rhetoric is the best tool for the defense of visible rhetoric.
So, try to convince me (heck, try to convince yourself!) that this image is not rhetorical.
This image, found on the anti-abortion site stopthealcu.com, is certainly one of the least gruesome examples of visible rhetoric directed at the elimination of abortion. If you have the stomach for it, do an image search for abortion. Talk about some serious persuasion! If you don't think the results you get are rhetorical, then I'm not sure anything will convince you that visible rhetoric is a discipline in its own right ... and a powerful one, at that.