Wine is so strange and potent a thing that it has been used in the central ritual of religion in one place and time, and attacked by a virago with a hatchet in another. There is only one other thing in the world that is capable of stirring and altering men's minds to the same extent, and that is the coherent expression of thought. That is man's chief miracle, unique to man. There is no "explanation" whatever of the fact that I can make arbitrary sounds which will lead a total stranger to think my own thought. It is sheer magic that I should be able to hold a one-sided conversation by means of black marks on paper with an unknown person half-way across the world. Talking, broadcasting, writing and printing are all quite literally forms of _thought transference_, and it is this ability and eagerness to transfer and receive the contents of the mind that is almost alone responsible for human civilization.
If you agree with this, you will agree with my one main idea, _i.e._, that the most important thing about printing is that it conveys thought, ideas, images, from one mind to other minds. This statement is what you might call the front door of the science of typography. Within lie hundreds of rooms; but unless you start by assuming that _printing is meant to convey specific and coherent ideas_, it is very easy to find yourself in the wrong house altogether.
Before asking what this statement leads to, let us see what it does not necessarily lead to. If books are printed in order to be read, we must distinguish readability from what the optician would call legibility. A page set in 14-point Bold Sans is, according to the laboratory tests, more "legible" than one set in 11-point Baskerville. A public speaker is more "audible" in that sense when he bellows. But a good speaking voice is one which is inaudible _as_ a voice. It is the transparent goblet again! I need not warn you that if you begin listening to the inflections and speaking rhythms of a voice from a platform, you are falling asleep. When you listen to a song in a language you do not understand, part of your mind actually does fall asleep, leaving your quite separate aesthetic sensibilities to enjoy themselves unimpeded by your reasoning faculties. The fine arts do that; but that is not the purpose of printing. Type well used is invisible _as_ type, just as the perfect talking voice is the unnoticed vehicle for the transmission of words, ideas.