picture for the picture's sake, our whole interest is turned to the expression and is turned away from that which is expressed.
It is these latter cases with which we are concerned in our present analysis: we are not interested in facts but in the way in which facts can be expressed. This means that we have nothing to do with content. To express is to leave content out of consideration. It is by its content that the original is distinguished from all its possible pictures, reproductions or representations. If we were to use old fashioned philosophical terms we might compare it to the "haecceitas" of the scholastics or speak of it as the "principium individuationis". The picture could not have the same content as the original (the reader must again excuse my incorrect language) without being the original itself, it would no longer be an expression of it. And it is the nature of expression into which we are inquiring here.
10. Transportation and expression.
There is still another way of formulating the insight we have gained. In ordinary life we may distinguish between communication by transportation and communication by expression. The first consists in simply taking the thing or fact in question and putting it in the presence of the person to whom it is to be communicated; the second consists in describing it to him or her, or sending a photograph or drawing of it, or telling about it in some way or other.
This distinction can well be made in everyday life, but it may prove misleading when we try to apply it to the subtle problem with which we are concerned. If I take the green leaf from my desk and send it to a friend he will see and touch the same leaf that I have seen and touched before, the leaf "itself" will have been transported to him. And yet it will not be quite the same leaf, as it certainly will have undergone certain changes in the meantime, and even if it had not changed there would be no identity in the logical sense, for some sentences about the leaf which were true propositions when the leaf was lying on my desk will not be so any more after it is in the hands of my friend (e.g. those referring to its place). In the strictest sense there is no transportation of an entity "remaining identically itself". Even the motion of a physical body through space is nothing but
