He was writing in first half of the 5th century AD. This idea that the universe is made for man to see, and its corollary, that man is made to see it governs how we paint in the naturalistic artistic traditions. The stylistic elements of baroque naturalism are generated from an analysis of how we observe the natural world and how this manner of observation of the beauty of creation, leads us to give praise to the Creator. If the work of man, in this case a painting, participates in the beauty of the cosmos then it too will raise the hearts and souls of those who see it to God through its beauty. By incorporating traditional harmony and proportion into compositional design, the artist or architect is creating something that participates in this cosmic beauty, described numerically. Similarly, by painting in such a way that stimulates a response in the way we observe it, which is the same as our reaction to the natural world, it is likely to raise our hearts and minds to God just as the beauty of creation does.
These considerations are only relevant when we are considering the natural observation of the world we live in now. The baroque tradition is one of these as it seeks to portray fallen man, ie 'historical' man, in such a way that his potential for sanctity through cooperation with God's grace is emphasised. It aims to give us hope that transcends any evil and suffering. This does not apply to artistic traditions that are trying to communicate something different, such as the iconographic which seeks to communicate eschatological man, mankind in union with God partaking of the divine nature.
How do we observe the natural world? When we look at the world around us the eye roves around the scene before it. At any moment on only the central part of the vision is in focus and coloured - to an angle of vision of about 15 degrees. Peripheral vision is monochrome - reflecting only tonal information, no colour - and blurred. This is the nature of the image that is on the retina at any moment. But this is not what we see in our mind's eye. The memory supplies additional information to complete the scene. Usually the information is given to the memory by prior observation of different parts of the same scene. For example, if I am talking to somebody. I spend most of the time looking at the face, most particularly the eyes and eyebrows, because they communicate most information about what the person is thinking and feeling. Other than that I would make the occasional cursory glance up and down the person and unless something unusual particularly catches my attention, I focus first on the eyes, then the mouth and the gesture of the hands. All of these communicate thought. The soul is revealed through the body.
Similarly when I look at the broader scene I naturally focus on points that interest me and these will reflect, generally, the hierarchy of being. I look first and longest at any people, second at any man made objects, such as buildings, then at animals and finally at plants. Of course unusual sights will cause me to look at things longer - if I saw a two-headed sheep, then I would probably focus a lot of my attention on that.
How does the painter make use of this? He supplies key focal points of interest in the painting, harmoniously placed relative to each other and on these focal points he gives most detailed and coloured information. The rest he depletes of colour and softens the focus. In order to make sure that the eye is attracted to these key points the artist not only provides more detail, and more colour, but also will introduce into the composition something that will attract the eye immediately. Generally there will be a heightened and sharpened contrast between light and dark at the key points, and the brightest colour, perhaps a red to draw the eye.
When the focal points arranged by the artist correspond to those foci that we would have looked at preferentially when presented with a scene, because they conform to the hierarchy of being for example, then viewing the work is a delight. We are given most information in those aspects that we would be most naturally interested in anyway and we are barely aware that this is what is going on. The observation of the painting is so natural.
If the artist seeks to overturn our natural curiousity by painting, for example, a cigarette butt on the floor every bit as detailed as the person standing beside it (as a photorealist would do), then we feel overloaded with detail and information and it creates a tension as we observe the painting.
However, one would not want to give that this hierarchy of observation is a rigidly defined set of rules that allow no room for manouvre. The skilled artist understands how much leeway there is and will (through these devices of variation in focus, contrast and colour) deliberately pique our interest in things he wants us to notice by directing us to them prefentially; or conversly play down details that otherwise we might be more interested in.
The contrast between portraiture and sacred art demonstrates this point. In a portrait, the aim of the artist is to demonsrate the uniqueness of the person. By a strong emphasis on the face of the individual the artist not only communicates the thoughts and feeling of the person, thereby communicating the fact that this human person is body and soul; but also he communicates the unique characteristics of the person which for most of us are most striking in our faces. These unique characteristics are the things that differentiate us from all other humanity.
If the artist is portraying a saint or Christ, then the task is slightly different. Certainly the artist must represent the characteristics of the person that identify him as unique. But there is an important need also to emphasise those aspects of the person that can be emulated by us, these are the general characteristics of a good man - virtue, holiness and so on. This is why we look to the lives of the saints. For this reason, the baroque sacred artist, relative to a portrait painter, plays down the facial features. So very often the face will be wholly or partially in shadow, while the thoughts and feeling are communicated through the gesture and posture. The whole person is emphasised. When I was learning in Florence, my teacher Matthew James Collins made this point to me directly in contrasting the aims of portrait painting, which we studied each morning, with figure painting, which we studied in the afternoon. The figure, he told me, should have the light moving up and down its length - particularly on the broader masses such as the thighs and torso, as this emphasises the whole person and this is what the baroque tradition sought to do.
I have shown examples of portraits and paintings of saints to illustrate the point, but what the artist is doing in order to emphasise the general aspects of humanity is not always so obvious. The effect of failing to do it is more obvious. Rather than convincing us that this is the Virgin Mary or Christ, painting looks like painting of the girl or boy next door posing in costume.
This ability to partially abstract the painting in accordance with our natural way of observing, even more than a lack of technical painting skill, is in my opinion what distinguishes the masters of the past from so many atelier trained artists of today. This visual language was developed out of a Christian understanding of the relationship between the human person and the cosmos. While it is possible to consider simply it as a traditional form, without linking it to a Christian ethos, and still paint well (John Singer Sargent, for example, was not a man of faith, to my knowledge), any artist is going to increase his chances of doing so, I would suggest, if he understands and accepts the end to which all of this is directed and how these stylistic elements conform to that end.
The landscape above is by Rubens. All the paintings below are by Ribera: the Lamentation over the Dead Christ, St Andrew, the Martyrdom of St Andrew and St Peter. These should be contrasted with portraits by him that follow: the Drinker, Girl with Tambourine and Clubfooted Boy.
