Part 1 Purposiveness of Vital Phenomena; Chapter 1 Purposiveness of the Most Elementary Physiological Phenomena; Chapter 2 Purposiveness of Generative and Regenerative Phenomena; Chapter 3 Purposiveness of the Phenomena of Pre-Established Adaptation; Chapter 4 Purposiveness of the Phenomena of new Adaptation; Chapter 5 Purposiveness of the Behaviour of the Lower Organisms; Chapter 6 Purposiveness of the Reflexes and Instincts; Chapter 7 Purposiveness of the Affective Tendencies; Chapter 8 Purposiveness of Mental Activity; Chapter 9 Purposiveness of Social Manifestations; Part 2 An Intermediate Solution between Vitalism and Mechanism; Chapter 10 Vitalism and Mechanism; Chapter 11 The Vitalistico-Energetic Solution; Chapter 12 Conclusion;