How did different people with different philosophies and ideologies attain the same enlightenment or did they not? Buddha attained enlightenment and so did Adi Shankaracharya, but their philosophies are different (not to mention ramanujacharya, nagarjuna and many others). Or is it the case that we can never really know who attains enlightenment? Well I know that there is similarity between Buddhism and Advaita Vedanta but at the core they are very different. How did they attain the same enlightenment knowing the real truth in two different ways? At least one of them is wrong.
Well some say the truth can be interpreted in different ways but if advaita says self exists and buddhism denies it there is a big problem you can't make them compatible with one another.