This talk was given on July 16, 2022 at the Fourth Annual Thomistic Philosophy and Natural Science Symposium For more information please visit thomisticinstitute.org. About the speaker: MARIUSZ TABACZEK, O.P., is a Polish Dominican and theologian. He holds Ph.D. in philosophical theology from the Graduate Theological Union in Berkeley, CA and Church Licentiate from the Adam Mickiewicz University in Poznan, Poland. After his studies at the GTU and a fellowship at the Notre Dame Institute for Advanced Studies he returned to Poland. For three years he worked as a researcher at the Thomistic Institute in Warsaw (Poland), a lecturer at the Pontifical Faculty of Theology in Warsaw and the Dominican School of Philosophy and Theology in Krakow, and a director of Studium Dominicanum in Warsaw. He then moved to Rome where he became a professor of theology at the Pontifical University of Saint Thomas Aquinas. He is also a researcher at the Thomistic Institute at the same University. One of the hallmarks of modern science is the ability to explain the workings of nature by detailed study of its pieces and parts. Organisms are understood as combinations of organ systems, which are made up of tissues, which are made up of cells, which are made of up complex chemicals, then atoms, and more fundamental particles. As successful as this methodological reductionism has been, it is still an open question how complete it can be. Can everything about complex biological systems be reduced to chemistry, and every detail of chemistry explained from fundamental physics? Do the organization and complexity of higher-level systems require additional tools to complete our understanding of the natural world? Do the answers to these scientific questions work for or against an Aristotelian and Thomistic understanding of nature and natural kinds, and how might those classical ideas be of use in contemporary science? The Thomistic Philosophy and Natural Science Symposium gathers expert scientists and philosophers to discuss the potential compatibility and mutual enrichment of the study of Aquinas' philosophy of nature and various forms of modern scientific knowledge in mathematics, physics, chemistry, and biology. The 2022 symposium included a day of lectures geared towards an introduction to Thomistic philosophy and the history of science, with a focus on complexity, simplicity and emergence. The rest of the symposium will have scientific experts discussing the understanding of complexity and simplicity in their own fields with one another and with philosophers.