The basic mitzva of learning Torah can be fulfilled minimally with Kerias Shema. This comes from a Gemara in Menachos (99b) which goes through several conflicting interpretations of the verse in Yehoshua which says "והגית בו יומם ולילה"; "and you will/shall contemplate it day and night." The same Gemara records a machlokes about whether it is a mitzva to tell this to the lay people - so they'll feel like they're already worth something and perhaps be motivated to do more; or it is forbidden to tell them - because this knowledge might cause them to be even more lax than they already are. Shach (YD 246:1) rules in accordance with Rava, that it is a mitzva to inform people of this.
There is another Gemara (Shabbos 31a) which discusses things that we will all have to give an accounting for in the future, and one of the things is whether or not we set aside time for learning. In this vein the Tur and Shulchan Aruch rule (OC 155) that one ought to set aside time each day for learning Torah. This is known as kevias ittim.
Question: Is the halacha of kevias ittim an absolute obligation which is separate from one's general obligation to learn each day - the one that is technically fulfilled through the evening and morning kerias shema? Or is the only absolute obligation the general mitzva of talmud torah as it is delineated in Menachos, and the Gemara in Shabbos is simply telling us the proper way to live (a Pirkei Avos/darkei hamussar kind of thing)?
I am leaning toward the latter understanding. Some reasons: 1) If you still have to be kovea ittim then it seems a bit disingenuous for the Gemara to say that one is technically finished with his minimum obligation of talmud torah after the morning and evening kerias shema. 2) If kevias ittim is an absolute obligation then I would assume it has some basis in Tanach. As far as I know the only relevant pasuk is והגית בו יומם ולילה.
What do you think?
(Thanks to Double AA for suggesting I post this.)