Bosch's complex
aesthetic style is derived from the
astoundingly
scatalogical theology of the fourteenth and fifteenth centuries. During this period, the quite complex
doctrine of the
Catholic church was matched by the proliferation of minor
sects, such as the
Cult of Joseph, and mystical religious thinkers like
Thomas a Kempis, who initiated the
asceticism of the
Devotio Moderna. In addition, there was an abundance of
folklore and
apocrypha, and plenty of general
superstition.
In his paintings' iconography, one can see the myriad referential symbols and narrative archetypes being used to convey a very conservative Catholic message. To this day, many art historians spend their time trying to track the derivation of symbols and ideas in his work to their contemporary sources.
For example, he frequently uses eggs in his scenes: people in eggs, half-egg-shaped humans, and so on. To many, this might seem to be a simple visual device with no greater meaning in any representational system; in the early part of the twentieth century, no one knew what it meant, and assumed it meant nothing. Scholars eventually discerned, however, that the egg was the symbol of alchemy, which was a considered a sinful pursuit during the late middle ages. People of Bosch's time would have recognized this, but many of his symbols are no longer widely understood today
Bosch is sometimes referred to as a surrealist, or as an extremely 'weird' artist, but his rigorously iconographical style was in fact a very specific (and the time intelligible) way of admonishing viewers to heed Catholic dogma.