Ow did the renaissance's emphasis on humanism spark scientific thinking?

The emphasis on humanism helped to spark scientific thinking because it lessened the reliance on religion to guide all rational thought. By giving more space for empirical thinking about the world that was not fully decided and pre-ordained by god it allowed for a revolution in scientific thinking. The focus on humans and the secular or non-religious world freed scientists of dogmatic ideology in their examination of the world and the universe. 

The humanism made people emphasise the potential in human beings and human brain. Instead of wondering about god and philosophical questions the thinkers focused on more down-to-earth issues. This led to quick development of social studies, architecture, art and biology. This was a chain reaction like when people quit believing that deseases were god's punishment and started to examine human body, they learned the basics of all living organisms, that led to development of chemistry and engineering medical tools etc...