We can commiunicate effectively via poetry, fiction and non-fiction our ideas and feelings. Materially, when the person is not in front of us it is done using pencil, paper, word-processor, internet, books, and other material devices. They play a mere supporting role in that communication, which can be of human ideas, perceptions and feelings.. The fact of their material nature is unimportant. When we take a chisel to stone or wood, when we put a brush or spatule to paper, canvas or another surface, when we capture on a silver base emulsion, or on a pixel array of a sensor, and then manipulate and print an image to silver base paper in a darkroom or an inkjet paper, we are also expressing what is on our mind and/or reacting to what we perceive. The question of doubt about capturing the "essence" of Paris or any other place raised the question of the nature of essence. Some likened the esence to the Eiffel tower, Edith Piaff or a Haussmann boulevard, and the essence may well be in part some of that. Or, it may be reflected as others maintain in its history or how the history has fashioned that city and, perhaps more importantly, the people who live in it. Or, by one defintion of "essence" that I personally feel to be important, it may be reflected by the spiritual and immaterial that is related to its existence. Ideas of the spiritual or immaterial that are contained in poetry, fiction, philosophy or other nonfiction are readily communicated by the physical instruments of communication that are books, internet, word processors, pencil, pen and paper. Ideas or statements of the immaterial have more difficulty being communicated by the physical devices of photography, painting and sculpture, although no doubt they can be, with some difficulty. Fast rewind now to the subject of essence, and accept for the moment that essence refers to an immaterial quality that evokes or describes (you may note that I prefer not to use the word define) a place or event. Substitute for essence any other immaterial quality or condition or thesis that you may wish to communicate. Then think of how photography, sculpture or art can describe or evoke those immaterial qualities using a material medium. A simple case. If Paris has all the qualities of the female, whatever than means to you in a social, philosophical, psychological, or even anatomical sense, how can you bring that out using a material medium (two-dimensional, paper, image) that does not relie on the advantage of using a written and spoken language that you have well mastered, and with which you can readily commounicate your thoughts? Some quite basic immaterial parameters (but not necessarily ideas or essences), like those of angst or sadness or joy can be communicated in portraits, or in scenes, and are among the most accessible conditions for the lens to communicate. They may make use of the photographer's imagination but also (and especially) very much the state of his subject, which is often read in his or her face or behaviour or in the use of composition, shadow and light. Beyond this, expressing immaterial concepts, ideas, or essences, is faced with the challenge of using such a physical medium as a paint brush and canvas, or a camera and print on paper or other material vehicle to achieve the result. If it is a language, it is one that does not have the advantage of the recognised writtten and spoken language eof communication. The attached photo is one in which I attempted, perhaps successfully, perhaps not (whichever is ultimately not of great importance to the problem of the OT, of material representing the immaterial), to communicate the immaterial. The material image is of a gravestone of a long dead soldier. He is dead, but remembered. The shadow is of a person who is apparently alive (we do not see her), yet who is being challenged by the gravestone on which her image is thrust. We are being reminded perhaps of an illusion of existence for which we have no better proof than a shadow without a body. How can you represent the immaterial by the material constraints of photography, or for that matter, painted or sculpted art? What do you think are the constraints of the medium and its advantages? Can it be done, even by a photographer of ample imagination? Any examples you have may help in establishing the capacity of photography in that regard.