{Early twentieth} century theory of perception organized around the idea that {perception acts on whole patterns, not just individual components}.
“Gestalt” in this context means {“pattern” or “configuration”}.
Gestalt principles describe {consistent patterns you use to organize ambiguous stimuli into forms}.
For example, the proximity gestalt principle suggests that {we tend to link close stimuli into groups}.
Among other phenomena, these principles attempt to explain how it is that you can see a photo of various objects and make inferences about what’s behind them in the scene. If one object is partially occluded by another, you can interpret the blocked object as a single obscured shape, rather than two complex shapes joined behind the blocking shape. And so on.