The book takes a journey through the ideas of the major Greek philosophers from the 6th to the 3rd centuries BC, primarily focusing on natural philosophy and the theory of knowledge, from both a diachronic and anachronic scientific perspective. Diachronic in the sense of attempting to place ourselves in the era in which they lived, stripping away our 21st-century biases, in order to assess their contributions to the understanding of nature and the world in general, in light of the relatively short history of humanity. As for the anachronic perspective, it seeks to discover how many of our current knowledge began to take shape 2,500 years ago and how many paths initiated back then led to dead ends. The work aims to demonstrate that the journey undertaken prior to Galileo and Newton is far longer than commonly believed, that Newton’s ideas about mass, force, space, and time were by no means obvious nor the only possible ones, and that there were numerous individuals who pondered extensively and in diverse ways about nature, knowledge, and the world centuries ago. Gaining a better understanding of the history of our collective thinking as a species helps us comprehend our present reality, both scientifically and philosophically, as well as our broader cultural context.