Is there any difference between the following sentences?
It would never have occurred to Stormgren, even a few days before, that he could seriously have considered the action he was planning now.
and
It would never have occurred to Stormgren, even a few days before, that he could seriously consider the action he was planning now.
I feel like the perfect infinitive in boldface in the first sentence is redundant since it moves the action further back into the past. I'd personally go with the second sentence.
The quote is taken from Arthur Clarke's book "Childhood's End".