How does a box work? A study in the qualitative dynamics of solid objects

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This paper is an in-depth study of qualitative physical reasoning about one particular scenario: using a box to carry a collection of objects from one place to another. Specifically we consider the plan, plan1 "Load objects uCargo into box oBox one by one; carry oBox from location l1 to location l2". We present qualitative constraints on the shape, starting position, and material properties of uCargo and oBox and on the characteristics of the motion that suffice to make it virtually certain that plan1 can be successfully executed. We develop a theory, consisting mostly of first-order statements together with two default rules, that supports an inference of the form "If conditions XYZ hold, and the agent attempts to carry out plan1 then presumably he will succeed". Our theory is elaboration tolerant in the sense that carrying out the analogous inference for carrying objects in boxes with lids, in boxes with small holes, or on trays can reuse much of the same knowledge. The theory integrates reasoning about continuous time, Euclidean space, commonsense dynamics of solid objects, and semantics of partially specified plans.

Original languageEnglish (US)
Pages (from-to)299-345
Number of pages47
JournalArtificial Intelligence
Issue number1
StatePublished - Jan 2011


  • Commonsense reasoning
  • Dynamics
  • Kinematics
  • Naive physics
  • Planning
  • Qualitative physics
  • Solid objects

ASJC Scopus subject areas

  • Language and Linguistics
  • Linguistics and Language
  • Artificial Intelligence


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