Meaning of "while it was not clear whether it was a case of pouring passion onto...

Here is the text:

Fortunately Koroku had not descended on them again. A young man of a compulsive and excitable temperament, he would pursue unremittingly whatever was uppermost in his mind, a trait that had been apparent in the Sōsuke of distant schooldays. On the other hand, when Koroku’s mood changed he became a different person, with a good-natured look on his face, as if the cares of yesterday were totally forgotten. Here too the brothers’ common blood showed: Sōsuke had been just like this long ago. Koroku had a relatively lucid mind and, while it was not clear whether it was a case of pouring passion onto his reason or cloaking his emotions in rational trappings, he was at any rate never satisfied with a proposition until he could discern its underlying logic; once he had done so, he would zealously push it to its conclusion. His will, moreover, was far stronger than his physical constitution might suggest, and his youthful impetuosity made him capable of almost anything.

Does it mean: when he was going to decide about something and it was not clear to him whether it was the case to act emotionally or logically he never decide until he find a logical answer and he did that?

I do not get the meaning of "pouring passion onto his reason" and "its underlying logic". and the whole phrase is unclear to me.

Source: The Gate by NATSUME SŌSEKI Translated by WILLIAM F. SIBLEY

while it was not clear whether it was a case of pouring passion onto his reason or cloaking his emotions in rational trappings, he was at any rate never satisfied with a proposition until he could discern its underlying logic; once he had done so, he would zealously push it to its conclusion

"Perhaps he was very passionate about logical reasoning, or maybe he used logic by adding it to his existing emotions to make them seem more rational or legitimate. I don't know which, if either, but he was certainly never satisfied that something was true without examining it logically first, and would always attempt to further apply logic to understand the consequences if he determined a proposition was true."