If "Memory" is only supposed to be used only on instants and sorceries, then it can be a subtype. If there are supposed to be "Memory" permanents though, then that should better be a supertype or card type. That's the purely technical aspect.

The greatest obvious issues with that are:

• Each of these cards basically has +1 card advantage. Fill your decks with "Memory" cards that also have that keyword ability and you never run out of cards. This ard is not cost with that in mind.
• Tutoring for an effect can be extremely strong. If you have generally useful cards with the "Memory" type, you basically tutor for whatever you need at no additional cost. Also games will be extremely consistent. That costs even more.

A really big issue is that you have a "Memory" card that can also search for more "Memory" cards.

Excessive shuffling is something WotC has been trying to avoid at lower rarities due to how disruptive is to the gameplay flow. So this mechanic seems to have a serious problem there from the get-go.

I also think there would be some other development problems as well. Like u could be picking 4+ copies of this for your limited deck where u could quite steadily discard opponents hand by chaining these together and once they ran out of cards u could just start chaining into something else. That is, the mechanic looks like infinite value to me.

"Memory" would make more sense as a subtype instead as supposed to supertype.

It looks to me like this is attempting to be something like "Learn/Lesson"... maybe you could return that keyword?