Meaning of "so divergent and even contradictory as to all but baffle definition"

I read the preface of Crime and Punishment by the Dostoyevsky, and I stumbled upon this sentence:

But besides that, these were novels of a new kind, their multiple planes so divergent and even contradictory as to all but baffle definition.

What does

"so divergent and even contradictory as to all but baffle definition."

mean ?

I understand that "multiple planes" means that his works were not clear and could have several hidden meanings. But I completely don't understand the second part of the sentence.

A little more context:

A new form, a new plan captivated me and so I began over again. I’m working day and night, and for all that I’m not working very much. A novel is a work of poetry. In order to write it, one must have tranquility of spirit and of impression  …” A novel, at least a Dostoevsky novel, is a “work of poetry”— that is, a simultaneous composition on multiple planes— and the critics can therefore be forgiven their perplexity about where to take hold of it, since the first perplexity of criticism is that it must speak monosemantically of the polysemous.

But besides that, these were novels of a new kind, their multiple planes so divergent and even contradictory as to all but baffle definition. So much so that one line of criticism, rightly noting the dramatic technique and high seriousness of Dostoevsky’s writing, has called his late works “novel-tragedies,” while another, with equal rightness, finds their roots in Ménippean satire and a carnival sense of the world.