We know information from the past (or for that matters information happening in different places) by people passing that information through a chain of narrators until it reached us. We can rest assured if those who passed information were authentic and were telling the truth.
It is a unique characteristic of Islam that valuable information has moved from generation to the next through chains of authentic narrators. Today no one can doubt about -for example- the five pillars of Islam, or that Muslims need to face Makkah during prayer, or that obligatory fasting is on the Arabic month of Ramadan and not Shawwal, and that Prophet Muhammad was sent not to Arabs only but to the entire population of earth including Jews and Christians, and so on. Even much less significant rituals were well preserved to the extent that a Muslim child knows about them for sure. For example, eating with the right hand and not passing in front of a praying person and many more.
One sees the value of this -for granted virtue of Islam- when compared with -for example- the Christianity. Many fundamental teachings of Prophet Jesus -peace be upon him- was lost, let alone minute things. Prophet Jesus never allowed venerating the cross, or allowing eating pork, or refraining from circumcision, or relaxing on rulings related to purification (for example taking a shower after sexual intercourse), etc. Many innovations were introduced and became official Christianity, and those who adhered to the real teachings of Jesus were branded as heretics.
The way of prayer that Christians pray today was never propagated to them through authentic narrators from Jesus, nor the fasting (which they started as forty days, then added ten more days, and shifted it to spring). Similarly, their religious festival of Christmas or Easter were never propagated to them from Jesus with a known authentic chain of narrators.
Muslims, on the other hand, had their complete code of Islam well defined before Prophet Muhammad – peace be upon him- left this world.
The other critical faculty is the art of reasoning in Islam. The Islamic materials that were propagated to the Muslims through authentic narrators have kept lots of rooms for the intellect to exercise intellectual activities and extract solutions from fundamental rulings of Islam. For example, the Quran told Muslims to explore the earth and ponder upon the creation of earth and heaven. Many verses of the Quran end up will calling the people of intellect to use this valuable gift of reasoning. Muslim scholars in astronomy, physics, biology, or mathematics never clashed with scholars of Quran and Hadith as was the case in Europe between the Church and the people of science.