If we build logically upwards from a few indubitables, the whole system must remain correct.
The indubitable effect of the potion convinced many unbelievers.
I wish you would stop doubting me.
- Keşke benden kuşkulanmaktan vazgeçsen.
I doubt which sentence is grammatically correct.
- Dilbilgisel olarak hangi cümlenin doğru olduğundan kuşkulanıyorum.