Scientists have not been content with just calling the human face “beautiful” if it meets certain ideals, or “ugly” if it doesn’t. They had to go out and measure proportions of nose to jaw, forehead to chin, and so on to establish why some faces are more appealing than others.
Typographers and graphic designers often choose typefaces for the very same reason they might fancy a person: They just like that person. For more scientifically-minded people, however, there are specific measurements, components, details, and proportions to describe various parts of a letter. While these won’t tell you what makes a typeface good, they will at least give you the right words to use when you discuss the benefits of a particular face over another. You can say “I hate the x-height on Such-a-Gothic” or “These descenders just don’t work for me” or “Please, may I see something with a smaller cap height?” and you’ll know what you are talking about. - Explorations in Typography