The author advocates a monistic philosophy that aims to reconcile empirical natural science with speculative thought, criticizing the persistent split between experimental researchers and metaphysical philosophers. He surveys evidence from evolutionary biology, comparative physiology, and anthropology to evaluate how far understanding of life, human origins, and causal connections has advanced, and argues for a unified nature-philosophy that integrates observation and general explanation. The text summarizes earlier studies, clarifies methodological aims, and offers a candid appraisal of contemporary knowledge while defending a coherent, naturalistic framework for addressing fundamental cosmological and biological questions.