The primary difference between the two, and the major break between Medieval and Renaissance thought. was the concept of the worth of the individual, a school of thought known as humanism. At the same time scientific experimentation and speculation became popular in the Renaissance period; previously they had been discouraged.
During the Medieval period, the prevailing school of thought was that humans were imperfect, depraved creatures struggling through a veil of tears in hopes of a better life beyond the grave. They were believed to be constantly subject to temptation from evil forces, including witches. For that reason, authority, in this case the authority of the church, was to be accepted without question. The prevailing educational theory was scholasticism which relied on two primary sources: the Bible and Aristotle, the latter only because it was believed that Aristotle's teachings harmonized with those of Scripture. Experimentation was dangerous as it might lead one into error, and error into sin, and sin into damnation.
With the birth of the Renaissance, scholasticism fell out of favor. Prevailing thought was that human beings were God's greatest creation and should be celebrated as such. This line of thought is illustrated in Renaissance art, which depicts human beings in realistic terms. Medieval art had been only symbolic, with people appearing similar to stick figures. Humanist scholars read the Bible and other classical texts in the original languages, thus developing a deeper understanding of its true meaning. Science which had been considered indistinguishable from religion was seen as an independent discipline and experimentation an avenue to truth.