Whenever I talk about proportion and harmony in art and architecture, many assume that I am referring to the proportion known as the Golden Section (often indicated by the Greek letter Φ). Indeed, when I started to look at these things, I assumed that the Golden Section was important too. However, to my surprise my investigations have lead me to believe that although it was known to past societies and cultures, it was not as important as we assume today. In fact, the idea that it was used by the ancient Greeks, the medievals or masters of the High Renaissance is, as far as I can work out, largely a myth. I have described before, here, here and here, how important symbolic number, proportion and harmony (expressed numerically or geometrically) was for artists and architects in the Christian tradition and how they were seen as a manifestation of the cosmic liturgy. The point is that it seems that the Golden Section, Φ, isn’t part of that tradition. Most of the books that I read justify their argument with a diagram as shown left, over the Leonardo self-portrait. In the diagram a grid placed has been placed over a copy of the drawing. This grid, to my knowledge, is not taken from information given by Leonardo himself in regard to this drawing, but is a modern superimposition. It appears very strongly that is just an array different rectangles, all relating to to Φ is some way, but otherwise arbitrarily chosen until their combination coincides with the main features of the drawing...and not very well at that. The eyes, the mouth, the tip of the nose, the chin (which is hidden) do not coincide with the lines drawn. This is typical. When you look at it, given the margin of error that is required to make it fit, you could justify just about any proportion you chose to apply.
My feeling is that the modern focus on Φ results from a modern, neo-pagan worldview in which the natural world is seen as the ideal of beauty. This is in contrast with the traditional Christian view that the world, although good and beautiful, is fallen and its beauty points us to something greater, which is ultimately the standard of Beauty, which is God. The Christian interest has always focused more on what it points to, that is to what the created world ought to be, rather than what it is.
If we assume that I am right and that the use of Φ in the past has been exaggerated in modern accounts of art history. Does this mean that it shouldn’t be used today? In my opinion, not at all! However, if we do decide to use it, it should be done so with discernment. We need to consider what precisely we feel that it symbolises and how it relates to the rest of the Christian tradition of harmonious proportion. If we consider it, for example, as a symbol of a fallen, imperfect world, then it should not be used in isolation, but should always be used in conjunction with other proportions that allow it, to use a musical terminology, to resolve to a more perfect harmony. It's just the same as using shadow in baroque painting, it must be overcome, so to speak, by the Light.
In the article below I describe my reasons for my conclusion. However, I still have an open mind on this matter. If readers can come up with accounts contemporary to the artists and architects that demonstrate it was used intentionally by them, then I will very happily change my view.