Upper level: b126 Temperament and personality functions
(Optimism)
Mental functions that produce a personal disposition that is cheerful, buoyant and hopeful, as contrasted to being downhearted, gloomy and despairing.
(additional explanation: The one to conflict with disappointment, gloominess, and despair by mental function to give birth to personal nature expressed to be filled with cheerfulness, cheerfulness, and hope. )