Reductionism is a method of explanation which assumes that the functioning of complex phenomena is reducible to the relationship between their simpler fundamental constituents. This practice is used in one form or another in almost all scientific fields: physics, chemistry, ecology, sociology, medical sciences, etc. Reducing complex systems to the mechanisms of their parts is risky – it overlooks the properties that can emerge from the system as a whole. These emergent properties may be unpredictable, unnecessary, or unprecedented and therefore must be observed from higher levels of the organization. There are several terms used to describe "anti-reductionism" or the belief that the whole is greater than the sum or its parts. For the sake of consistency, I will adhere to the term “holism” to represent this theory of explanation. I will examine talks by various philosophers who describe the use of reductionism in medicine: James A. Marcum explores the uses of reductionism and organicism (holism) in cancer research; Elisabeth A. Lloyd discusses socioeconomic aspects of human health; and Alfred I. Tauber explains the vital importance of holism in medicine. I will conclude with the belief that the integration of holism and reductionism, together, creates the most ethical approach in medicine, based on the epistemological challenges of reductionism in biological sciences and medicine, as well as the moral imperative that requires a holistic approach to understanding how human beings function. James Marcum (2005) uses cancer research as a model to see the importance of metaphysical presuppositions in guiding scientific studies. When one begins to study the deep complexity of biological systems and processes, ...... middle of article ...... usually provides the necessary bridge between knowledge obtained from reductionist studies and holistic approaches to obtain the best possible medical treatment (Marcum, 2005).Works citedLloyd, Elsabeth A. “Reductionism in medicine: social aspects of health”. Promises and limits of reductionism in the biomedical sciences. Ed. Van Regenmortel, Marc H. and David L. Hull. Chichester, West Sussex, England: John Wiley & Sons, 2002. Print.Marcum, JA “Metaphysical Presuppositions and Scientific Practices: Reductionism and the Organism in Cancer Research.” International Studies in the Philosophy of Science 19.1 (2005): 31-45. Print.Tauber, Alfred I. “The Ethical Imperative of Holism in Medicine.” Promises and limits of reductionism in the biomedical sciences. Ed. Van Regenmortel, Marc H. and David L. Hull. Chichester, West Sussex, England: John Wiley & Sons, 2002. Print.