Trusting someone means their interests encapsulate one’s own interests.

Evidence

It is compelling to see many interactions of trust and trustworthiness as similar to the interaction between Trifonov and the lieutenant colonel while it was ongoing. The trusted party has incentive to be trustworthy, incentive that is grounded in the value of maintaining the relationship into the future. That is, I trust you because your interest encapsulates mine, which is to say that you have an interest in fulfilling my trust. It is this fact that makes my trust more than merely expectations about your behavior. Any expectations I have are grounded in an understanding (perhaps mistaken) of your interests specifically with respect to me. — Russell Hardin, Trust and Trustworthiness, 66

Categorization

• DEFINE: This is the core statement of Hardin’s ‘encapsulated interest’ theory of trust — the central definitional framework of the book.
• XREF: Directly links to the reader’s purpose: the trusting party needs the trusted party’s interest to be causally connected to the continuation of the relationship — which requires observable monitoring capacity like the doctor’s wife’s sight. — connects to: Interests are relational and can include other beings without ceasing to be one’s own. — Val Plumwood, Feminism and the Mastery of Nature, 558