Final answer:
The shift from religious to natural explanations of the world started with the pre-Socratics in the 6th century BCE as they sought rational explanations for the universe, which was further developed during the Renaissance and solidified in the Enlightenment era.
Step-by-step explanation:
The first time period when people began to look for natural, rather than religious, explanations of the world can be chiefly associated with the Greek pre-Socratics, who emerged roughly in the 6th century BCE. These thinkers started to move away from mythopoetic explanations and instead applied rational inquiry to understand the cosmos, which they termed cosmology. During the Renaissance, a renewed interest in Greek humanism and scientific curiosity led to further questioning of theological accounts, and the Enlightenment in the 18th century solidified the shift towards observation and reason as the bedrock for understanding the natural world.
For example, figures like Copernicus and Galileo challenged prevailing religious views with observational evidence and mathematical logic, helping to foster an environment that would eventually celebrate and institutionalize scientific thinking and empirical research. The movement from mythos to logos, that is, from supernatural myths to rational and logical explanations, characterizes this profound shift in thought.