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The majority of work in knowledge representation has dealt with the technicalities of relating predicate calculus to other formalisms and with the details of various schemes for default reasoning. There has almost been an aversion to addressing the problems that arise in actually representing large bodies of knowledge with content. However, deep, important issues must be addressed if we are to ever have a large intelligent knowledge-based program: What ontological categories would make up an adequate set for carving up the universe? What are the important facts and heuristics most humans today know about solid objects? In short, we must bite the bullet.