Abstract: Manifest Activity examines Thomas Reid's efforts to provide answers to a host of traditional philosophical questions concerning the nature of the will, the powers of human beings, motivation, and the relation between human action and natural change. The concept of ‘active power’ stands at the centre of Reid's philosophy of action. He holds that actions are all and only the events of which some creature is the ‘efficient cause’, and he thinks a creature is the efficient cause of an event just in case it has the power to bring that event about and exerts it. Reid's conception both of human actions and changes in nature is deeply teleological. He holds that to exert a power is to direct an event towards an end, and he holds that all changes, whether actions or events in nature, flow from the exertion of power. The book explains the details of this view, Reid's reasons for holding it, and its implications to our understanding of action, agency, and our relation to the natural world.

Keywords: action, agency, cause, change, event, Free Will, Hobbes, Hume, Intention, Laws of Nature, Liberty, Morality, motivation, natural world, Possibility, power, Reid, Teleology, Volition, will