Out of interest was Muhammad a good logician? He established his own criterion (apparently from Allah) via which he commanded Muslims to recognize his so called divinity and integrity, but where is the subjectivity in that? What non-Islamic principles can prove his authenticity? Put simply, other then Muhammad's word what else is there to say Islam truly is the veracious path to God? Isn't it a defeatist mentality when da'wah givers penultimately proclaim that for not accepting Islam you will burn in hell?