Society, biology and ecosystems; conscience, life and ethics; knowledge, biodiversity and justice. A perspective associated with an integral way of thinking and sustainable science. It is possible to make advances in our knowledge of life and health by a medical, scientific and economic approach that respects all forms of life and health and the planet's balance. In this book we offer an analysis of this process from the perspective of two individuals. From the perspective of the history of ideas, Àngels Canadell points out the bases on which the reductionist view of science and philosophy has been based and the relationship between this path and the loss of ethical and fundamental reference points. He considers it necessary to question scientific methodology and proposes that the natural sciences work hand in hand with philosophy and with the study of conscience. A philosophy that must assume the responsibility for constructing an interpretation of the cosmos and of life in terms of processes and interactions. From the point of view of social movements, Jesús Vicens analyzes new systematic science, extracting from its notions a model that is applicable to knowledge and social transformation. Running through the principal challenges we must confront in the new century, he uses the same language to link economic and social imbalances, the destruction of ecosystems and the internal ruptures of contemporary man. The line of argument of this dialogue is the notion of interdependence that from animist and Eastern cultures on the one hand and from the language of new physics and biology on the other, comes together in the current state of the world to build a new framework of action and intelligibility.