According to Osho, it’s possible but rare to grasp the Tao without a teacher; the decisive factor is your alertness. If you are truly awake, even birdsong or a book can trigger awakening; if you’re asleep, even a living Buddha is useless. Teachers are catalysts, not substitutes for awareness—so while the exception exists, it is very nearly impossible.
Yes—but only if you’re very awake inside; otherwise even the best teacher can’t help.