But let us be careful not to confound unity with simplicity of plot.

The former does not in any way exclude the secondary plots on which the principal plot may depend.

It is necessary only that these parts, being skilfully subordinated to the general plan, shall tend constantly toward the central plot and group themselves about it at the various stages, or rather on the various levels of the drama.

Unity of plot is the stage law of perspective.
"But," the customs-officers of thought will cry, "great geniuses have submitted to these rules which you spurn!" Unfortunately, yes.

But what would those admirable men have done if they had been left to themselves?
At all events they did not accept your chains without a struggle.