The final approach to ta’amei hamitzvot is that of the Maharal. I would call this the “segulah” approach, and it is the one closest to mysticism. The Marharal offers an analogy that I think captures the essence of his position: just like a seed produces a certain type of tree, and it makes no sense of ask why it produces specifically this type of tree and no other (at best we can explain what processes occur that lead to the result, but not why specifically those processes and no others exist), so too, the nature of a spiritual soul demands a certain type of behavior and attitude, and it makes no sense to ask why these elements are essential for the soul’s existence and nourishment and no others.
This does not mean that there are not benefits to mitzvos that meet our physical needs. However, those benefits are not external reasons for the mitzvos; those benefits are outcomes of the spiritual goodness which is inherent in the mitzvah itself. One need not wonder (as we asked on the Ramban) what value a mitzvah has if the doer is ignorant of the crucial didactic element – how does “bala matzah yatzah” work? – any more than one would wonder how an antibiotic cures an illness for someone who has no knowledge of science. Yes, that didactic element can result from doing the mitzvah, but it is not the reason behind the commandment.
The appraoch also avoids the reductionist elements of the Rambam and Ramban. The Torah is not a book of medicine or psychology alone – the Torah is a book of spiritual growth, sui generis, which may happen to pay dividends in other areas. It is understandable why one should not say “ee efshi b’basar chazir” because the prohibition against pig has nothing to do with it being an unhealthy animal or with inculcating certain ethical eating habits – it has to do with the interaction between the soul and the environment, something which is not reducible to simple rational rules that apply in other areas.
As an example of a debate that may depend on these issues, take a look at this exchange between by BIL, R’ Yosef Bechoffer, and a on whether mitzvos’ value is “salvic” (i.e. to save one’s soul, which sounds very Xstian), or to improve moral character.
So far I’ve set out the shitos with some argument, mostly in favor of the “segulah” approach because I find it appealing. But there is more to be said in defense of the other side, and some practical upshot which I’ll save for a summary. Stay tuned….