exists throughout a particular trajectory of space and orientation over a particular duration of time, and which is located in the world of physical space (i.e., as studied by physics). This contrasts with abstract objects such as mathematical objects which do not exist at any particular time or place. Examples are a cloud, a human body, a banana, a billiard ball, a table, or a proton. This is contrasted with abstract objects such as mental objects, which exist in the mental world, and mathematical objects. Other examples that are not physical bodies are emotions, the concept of "justice", a feeling of hatred, or the number "3". In some philosophies, like the idealism of George Berkeley, a physical body is a mental object, but still has extension in the space of a visual field. See also Abstract object theory Deformable body Human body Non-physical entity Physical model Rigid body Ship of Theseus, a thought experiment about an object's identity over time External links Concepts in metaphysics Concepts in physics Mechanics Ontology