f an assertion is the result of a person or external program asserting a sentence into the KB, at that time the asserter must specify which microtheory the sentence is to go in. Some interfaces for knowledge entry may not require the user to specify a microtheory for new assertions, and will then either try to choose the right one or will use #$BaseKB as a default. If you use such an interface make sure you know what the default behavior is, because the BaseKB is usually far too general a place for new know