which, according to aerodynamics, can't fly--but does?) What Hume implies is: (1)it is very impracticable not to assume that the real world exists,and(2) day-to-day living is very difficult if one tries to operate on the assumption that he knows nothing about the real world There are few philosophers of the modern world who would not question, to some extent, the conclusions of Berkeley and Hume. After more than two centuries of debate, we now have adequate reason to assume()that the real world exists and(2) that we have at least a working knowledge of that world. It is the nature of that working know ledge which is still cause for concern 15 If these conclusions are comforting, our philosophers have made three points which may seem less so. The following arguments seem basically sound and still and today as starting points for an understand ing of the nature of knowledge () We know only our subjective experience, which begin with sensory reaction and ends with the fabrication of knowledge. This appears to be an inescapable limitation (2)Accordingly, we cannot experience directly the real world of objects /events Neither matter nor the principles of motion are directly perceivable ()Our knowledge of the real world consists solely, therefore, of inferences which we make on the basis of our experience 16 In summary, what is the nature of our knowledge about the real world of objects/events? Our knowledge of reality is composed of ideas our minds have created on the basis of our sensory experience. It is a fabric of knowledge woven by the mind Knowledge is not given to the mind; nothing is "poured"into it. Rather, the mind manufactures perceptions, concepts, ideas, beliefs, etc, and holds them as working hypotheses about external real ity. Every idea is a(subjective)working model which enables us to handle real objects/events with some degree of efficiency. But ideas in our heads are not realities; they are but tools which enable us to deal with reality It is as though we drew nond imensional maps to help us understand four-dimensional territory. The semanticists have long reminded us to beware about confusing any sort of map with the real landscape The map is not the territorywhich, according to aerodynamics, can't fly---but does?) What Hume implies is: (1) it is very impracticable not to assume that the rea1 wor1d exists, and (2) day-to--day living is very difficult if one tries to operate on the assumption that he knows nothing about the real world. There are few philosophers of the modern world who would not question, to some extent, the conclusions of Berkeley and Hume. After more than two centuries of debate, we now have adequate reason to assume (l) that the real world exists and (2) that we have at least a working knowledge of that world. It is the nature of that working know1edge which is still cause for concern. 15 If these conclusions are comforting, our phi1osophers have made three points which may seem less so. The following arguments seem basically sound and still stand today as starting points for an understanding of the nature of knowledge. (l) We know only our subjective experience, which begin with sensory reaction and ends with the fabrication of knowledge. This appears to be an inescapable limitation. (2) Accordingly, we cannot experience directly the real world of objects /events. Neither matter nor the principles of motion are directly perceivable. (3) Our knowledge of the real world consists solely, therefore, of inferences which we make on the basis of our experience. 16 In summary, what is the nature of our knowledge about the real world of objects/events? Our knowledge of reality is composed of ideas our minds have created on the basis of our sensory experience. It is a fabric of knowledge woven by the mind. Knowledge is not given to the mind; nothing is "poured" into it. Rather, the mind manufactures perceptions, concepts, ideas ,beliefs, etc., and holds them as working hypotheses about external reality. Every idea is a (subjective) working model which enables us to handle rea1 objects/events with some degree of efficiency." But ideas in our heads are not realities; they are but tools which enable us to deal with reality It is as though we drew nondimensional maps to help us understand four-dimensional territory. The semanticists have long reminded us to beware about confusing any sort of map with the real landscape. "The map is not the territory