# Section XIV: Of the Idea of Necessary Connection explained — A Treatise of Human Nature > Chapter companion for A Treatise of Human Nature by David Hume. ## What happens Hume argues that the idea of necessary connection, or power, cannot be derived from any single instance of cause and effect, but arises from the customary transition of the mind after repeated similar conjunctions. He rejects the notion that power resides in objects, insisting it is a perception of the mind. He provides two definitions of cause, one as a philosophical relation and one as a natural relation, emphasizing the mind's determination to pass from one idea to another. ## Themes in this chapter ### Empiricism and the Primacy of Impressions Hume insists that the idea of power must be derived from impressions, not from reason or innate ideas. ### Custom and General Rules The idea of necessary connection is explained as a product of custom and habitual transition, not as a property of objects. ## Character check-ins ### David Hume Author and narrator, presenting his doctrine on necessary connection. ## Key lines > the simple view of any two objects or actions, however related, can never give us any idea, of power, or of a connection betwixt them: that this idea arises from the repetition of their union: that the repetition neither discovers nor causes anything in the objects, but has an influence only on the mind, by that customary transition it produces Merely observing two objects together, no matter how related, cannot give us the idea of power or connection; this idea comes from repeated experiences, which only affect the mind by creating a habit of transition. _Hume's core argument that necessity is a mental projection from custom._ > the same propensity is the reason, why we suppose necessity and power to lie in the objects we consider, not in our mind that considers them We mistakenly attribute necessity and power to external objects because our mind tends to spread its own impressions onto them. _Explains the psychological bias that leads to the false belief in objective necessity._ > A cause is an object precedent and contiguous to another, and so united with it, that the idea, of the one determines the mind to form the idea of the other, and the impression of the one to form a more lively idea of the other. A cause is an object that comes before and is next to another, and is so connected that thinking of one leads the mind to think of the other, and experiencing one makes the idea of the other more vivid. _Hume's second definition of cause, emphasizing the mind's determination._ ## Links - HTML: https://www.betterreads.online/discover/a_treatise_of_human_nature_se/chapters/section-xiv-of-the-idea-of-necessary-connection - Book: https://www.betterreads.online/discover/a_treatise_of_human_nature_se - All chapters: https://www.betterreads.online/discover/a_treatise_of_human_nature_se/chapters