But do believe that the book you value will hold you accountable for breaking the oath?
That’s the point - that a non religious oath is emptier gesture because you don’t expect the thing you’re swearing on to hold you accountable.
The point is not that she shouldn’t be able to swear on Sagans book. Or that it doesn’t have meaning to her. Just that there are inherently religious roots to these oaths and when you remove them the oath makes less sense.
To a non-believer swearing on Sagan's book has exactly the same "accountability" as swearing on a Bible (i.e. none of these books will hold you accountable in any way whatsoever), so the non-religious oath is exactly as meaningful as swearing on a Bible; it's not an emptier gesture, it's the same.
This is obviously incorrect. It sounds like you are assuming that the ONLY significance of swearing on a bible is that you believe that God will punish you? Well, that’s wrong, the ritual has other significance.
> that a non religious oath is emptier gesture because you don’t expect the thing you’re swearing on to hold you accountable.
If you're of the mindset that the value of an oath is that an external force will hold you accountable to it, then I think the nonreligious oath is a more powerful one, because the people you're making the oath to will hold you accountable in the here and now, not some ephemeral being at some point after you die.
That’s the point - that a non religious oath is emptier gesture because you don’t expect the thing you’re swearing on to hold you accountable.
The point is not that she shouldn’t be able to swear on Sagans book. Or that it doesn’t have meaning to her. Just that there are inherently religious roots to these oaths and when you remove them the oath makes less sense.