In general terminology, presupposition is consider as negative opinion or supposition about something that is not recognized before (perceive and examine). In religion terminology, the meaning of presupposition could be interpreted with a word al dzon. This word is not always negative connotation, but could be positive. Positive presupposition is called Husnudzdzon and negative presupposition is called Suudzdzon.
Muslim has no right to believe and trust anything based on presupposition, because it can’t bring us to the truth. “But most of them follow nothing but fancy; truly fancy can be of no avail against truth. Verily Allah is well aware of all that they do.” (Q.S 10:36)
Presupposition in faith is forbidden in Islam. Those who adore idolatry beside Allah have no strong belief. It comes from merely presupposition. ‘Behold! Verily to Allah belong all creatures in the heavens and on earth. What do they follow who worship as His ‘partners’ other than Allah? They follow nothing but fancy; and they do nothing but lie.’ (Q.S 10:66)

Following what majority people do doesn’t mean it is right. That may bring us to heresy and rebelliousness because of presupposition. “Wart thou to follow the common run of those on earth, they will lead thee away from the way of Allah. They follow nothing only conjecture, they do nothing but lie.” (Q.S 6:116)
Muslim who makes Al Qur’an as the way of life has no right to presuppose negative to other people. Such way is a sin that must be avoided. Allah spoke, “O ye who believe! Neither avoids suspicion as mush (as possible) for suspicion in some cases is a sin; and spy out on each other, nor speak ill of each other behind their backs. Would any of you like to eat the flesh of his dead brother? Nay, ye would abhor it, but fear Allah, for Allah is Oft-returning, Most-Merciful.” (Q.S 49:12)
Islam just allows Muslim to presuppose and be careful to the information given by godless people so that we are not deceived and harmed. “O Ye who believe! If a wicked person comes to you with any news, ascertain the truth, lest ye harm people unwittingly and afterwards become full of repentance for what ye have done.” (Q.S 49:6)
Muslim is ordered to presuppose positive to Allah and all things He gave. Only the hypocrites and infidels who presuppose negative to Allah, as Allah spoke, “And that He may punish the hypocrites, men and women, and the polytheists, men and women, who imagine an evil opinion of Allah. On them is a round of evil. The wrath of Allah is on them. He has cursed them and got hell ready for them and evil is it for a destination.” (Q.S 48:6)