| Mel555 |
That may be a bit too far. You can share their senses, but generally not their spell effects.
There are specific spell effects that will get shared because of some other sharing rules between the Summoner and Eidolon. Spells that change the number of actions are shared, but not spells that only give restrictions on actions (such as one that limits movement speed). Spells that affect Hit Points get shared in a fashion - but it is unclear if spells giving Temporary Hit Points is shared or not (there is an entire thread on that one).
But I don't think anyone is going to argue the case that Spider Climb will be shared to both the Summoner and Eidolon. Movement speeds are not shared, and spell effects are not shared through a general rule.
So I would say the same about Organsight. The spell effect is not shared.
For lore description of that mechanical ruling: The other of the pair can't get a fully precise location of the viewed organs sufficient to gain precision damage or bonuses to checks.
I guess my only thought on that then is if it were the spell see invisibility or darkvision instead and shared senses if that would be the same. Since the spells are mainly based on the sense of sight. Though I would assume once dismissing shared sense the darkvision wouldn't work, but one would still know the last place they saw an invisible creature or organs.