Though we may never be able to comprehend human life, we know certainly that it is a movement, of whatever nature it be. The existence of movement unavoidably implies a body which is being moved and a force which is moving it. Hence, wherever there is life, there is a mass moved by a force. All mass possesses inertia; all force tends to persist
The Tesla Papers (ed. Adventures Unlimited Press, 2000) - ISBN: 9780932813862