A couple of photography exhibits challenge some cherished beliefs about truth. In Australia, one explores photographs as one of the “most problematic forms of visual representation.” Another in the Boston area exposes the limits of digital truth in contemporary photography. And it would be wrong of me not to mention ParkeHarrison, whose work recently has gotten a lot of attention, in part because they do in the darkroom what many people now do in Photoshop.

Truth is a lot more flexible than we want to let on. Our understanding of incidents and even entire systems of belief depend to a certain extent — often a great extent — on cultural upbringing and our own history. This isn’t always a popular belief in the U.S. Several guests on public radio (the happy radio home of America’s intellectuals and self-styled elites) savaged postmodern relativism.

I, for one, know the camera lies when I want it to and suggests subtle untruthes even when I don’t intend it. What falls outside the frame doesn’t exist for most who view a piece of the world through the photograph. “Nature” photographs often suggest a world free of people, despite being composed by someone who had to walk from the car to the trail or boardwalk (and ocassionally wait for other people to get out of the frame). And Brockton might not be as bad as some images suggest . . . or maybe it is.