At the beginning of this week's parsha, we learn about the para aduma (literally: "red cow") that was used as part of the purification process of the ritual impurity that comes through contact of a corpse. This mitzva (commandment) is called a chok (literally: a decree), for it is not expected to be understood by man.
The Chovos haLevavos in his introduction to his sefer speaks about how there are two different types of mitzvos: 1) mitzvos that we would have said from our own common-sense, like honoring ones' parents and giving charity, and 2) mitzvos that we would not have said from our own common-sense, like the prohibition of meat and milk (as well as this mitzva of para aduma).
However, my friends, there is no such thing as a mitzva that goes against common-sense! We are allowed to think! The whole point of the Torah is actually just to "enhance" our common-sense (like he speaks about it in Sha'ar Avodas ha'Elokim). (And of course, everything with a rebbi that understands you and knows how to bring out the best of you).
