Boney, unironically speaking, could "missile knows where it is because it knows where it isn't" logic be used as a targetting component for a Ulgu spell?
Like as a basis for a Homing Shadow Knife (Or something else I dunno) spell:
The Homing Shadow Knife knows where it is at all times. It knows this because it knows where it isn't. By subtracting where it is from where it isn't, or where it isn't from where it is - whichever is greater - it obtains a difference or deviation. The guidance spellsystem uses deviations to generate corrective commands to drive the Homing Shadow Knife from a position where it is to a position where it isn't, and arriving at a position that it wasn't, it now is. Consequently, the position where it is is now the position that it wasn't, and if follows that the position that it was is now the position that it isn't. In the event that the position that it is in is not the position that it wasn't, the spell has acquired a variation. The variation being the difference between where the Homing Shadow Knife is and where it wasn't. If variation is considered to be a significant factor, it too may be corrected by the Caster. However, the Homing Shadow Knife must also know where it was. The Homing Shadow Knife guidance spell scenario works as follows: Because a variation has modified some of the information that the Homing Shadow Knife has obtained, it is not sure just where it is. However, it is sure where it isn't, within reason, and it know where it was. It now subtracts where it should be from where it wasn't, or vice versa. And by differentiating this from the algebraic sum of where it shouldn't be and where it was, it is able to obtain the deviation and its variation, which is called error.
The missile copypasta is certainly confusing enough to most people to create Ulgu I reckon.