Two Types of Chumros

R. Moshe Chaim Luzzatto discusses chumros, stringencies in Jewish law, twice in his book Mesillas Yesharim in very different contexts: in chapter 4, while discussing the ways of acquiring the trait of zehirus (watchfulness), the first and lowest of the traits discussed in the book; and in chapter 14, while describing the different aspects of the trait of perishus (asceticism). The question is why R. Luzzatto discusses the same topic as being part of two very different religious traits.

I believe that the answer is that there are two types of chumrah:

1. Behaving strictly when one is unsure what the law is.
2. Following minority opinions that are stricter than the established law.

Part of the trait of zehirus is to be strict when one is unsure either of what the conclusion is of a legal discussion or how to apply the law in a particular case. But if one knows that halakhah permits an act, even if there is a debate about it but a definitive pesak has been given to you, then even someone who has mastered the trait of zehirus may perform it.

Perishus is going beyond the law. One refrains from something that is technically permitted due to perishus, asceticism. Even though a legal debate has been concluded in favor of permitting this act, an ascetic (a parush) may choose to be strict for a minority opinion.

I think it should be clear from the Mesillas Yesharim that this latter attitude should not be dismissed or frowned upon. However, it is a form of asceticism and should, presumably, be accompanied with the other forms of asceticism mentioned in the same chapter.

(See also R. Doni Goldstein's article in the first issue of Hakirah - PDF)