Science made some progress in the middle Ages but the spirit of modern science was born with the renaissance. Science in the middle ages struggled against restrictions and there were many fetters to be destroyed before it could continue unhampered. Superstitions were common and to the masses were much more acceptable then were scientific explanations. The Renaissance brought about an interest in all things pertaining to men and the thirst for new achievements led to a critical observation of natural phenomena. The spirit of learning was manifested in science. Scientists of the 16th century made the first effective protest against the medieval scientific method of accepting theories before investigation had verified them. Francis Bacon pointed out that classical scientific conclusions did not represent mature knowledge and implored men to explore the realms of nature. Descartes brought out the necessity of questioning everything. He was the forerunner of science.