“Vertical convergence” – You want truth, or drama?

[Maris Rusis]

A couple of careers ago I actually got paid to do philosophy. I vaguely recall a few of the principles. Some extremely condensed abstract philosophising follows:

Both views of the Seagram building, the one with vertical convergence and the one with parallel sides, are "true". Truth exists and is a concept that applies only to propositions. So what propositions are implied in the two views of the Seagram building?

An easy way into unfolding the problem is to borrow a concept from cybernetics - the black box. A black box is a system that converts an input into an output via a fixed set of rules. We don't need to know the rules, just that they are fixed. Gratifyingly, the system works just as well backwards. If we have an output we can predict the input exactly. Photography works like a black box.

In both pictures of the Seagram building there is a one to one correspondence between points in the picture and points on the actual Seagram building. That correspondence is the transfer function that happens inside the photographic black box. Given either photograph and the transfer function used to make it then it is possible to reconstruct the actual appearance of the Seagram building itself. The two views, convergent and non-convergent, are the outputs of two different but self-consistent black boxes.

The basis of photographic truth lies in the fix-ed-ness of the transfer function that works in the heart of the photographic black box. Conspicuously, a fixed one to one correspondence of points in the picture to points in the subject is not guaranteed in painting, drawing, or digital picture making. These processes may support some true propositions but photographic truth isn't one of them.

[paulr]

Both views of the Seagram building, the one with vertical convergence and the one with parallel sides, are "true". Truth exists and is a concept that applies only to propositions.

And if you take the most common (unstuddied) proposition, that a photograph should look the way the world looks to our eyes, both views are necessarily false.

[peter ramm]

Maris, when I taught clinical neurobiology I would start the first lecture with "Everything I am about to teach you is false. However, it is the best I can do at the moment." This really pissed off some of the students (particularly med students) while others accepted that what is practical and what is true are not the same - and that this matters.

Today's untruth: Primary leverls of the visual system maintain a highly distorted representation of the external world. The ordered structure we experience is rendered and perceived, not seen. Perception is different for each of us. There is no single path to a good photograph.