On the painting Temperament
The verb 'temper' has its origins in the idea of mixing and modifying, stretching and restraining, altering, and bringing into proper proportion. It has some of these general meanings whether applied, for example, to the tempering of metal, the tempering of human emotions, or the tuning of musical instruments. In particular the last two of these are connected in the idea of temperament.
Temperament in we humans is some kind of balance between volatility and calm, and the balance of our dispositions or tendencies towards particular psychological states. Four or five hundred years ago or so, it was still widely thought that such characteristics in us were determined by astrology. The universe itself was thought to be structured on the ratios and proportions of musical harmony, and the way in which these ratios or proportions either fit together, or don't fit together, arithmetically, was a science in its own right. This was 'the science of music', as it was once studied at Oxford.
A musical temperament is a way of fitting together the precise tuning of the notes of a musical scale, and is usually understood in terms of the arithmetic ratios associated with musical intervals. This precise tuning of the notes in a musical scale that we might apply to musical instruments, is not something that is just already a given, in nature. Different harmonies appear in nature, between musical sounds, but the creation of a fixed musical scale through which we can fluidly and continually create various harmonies, as they might naturally occur between notes, is something that we have to do for ourselves. And it necessarily involves modifying, restraining, stretching, and altering, these otherwise pure harmonies, in order to fit them all together.
A similar kind of "tuning" can happen in our own inner experience of being, in the interplays that arise in our emotional and psychological self. And the same kind of harmonising and tempering principles are also expressed in the visual arts, although there it is not usually called temperament. Nonetheless, every artist knows that in the essence of a painting is a balance, proportion, or temperament of geometry and color, in which nothing, really, has an absolute value, in isolation from the whole. The import and effect of everything is determined by its place in the whole, and by its relation to what else appears. No color, shape, or form, is ever an absolute in its own right, its qualities are affected as much by what is around it, as by what is inherent in itself.