Once lines have been hardened into the shapes of letters of the alphabet, their only function is to form words and sentences. They march in straight rows, following the commands of their master, punctuation.
But ah, before that stage, when a line is still free and retains all of its original primordial wildness, it can do a thousand things and communicate in a thousand ways.
Excerpt from a drawing by Saul Steinberg
The designer Milton Glaser emphasized the potential of a simple pencil line:
There is no instrument more direct than a pencil and paper for the expression of ideas. Everything else that interferes with that direct relationship with the eyes, the mind, the arm and the hand causes a loss of fidelity.... I like the idea that this ultimate reductive simplicity is the way to elicit the most extraordinary functions of the brain.The domain of the created line began with the first bubbling urschleim, before your words had consonants...
Prehistoric cave art from Queensland, Australia
... and extends to the most exalted and sublime heights where the air is too rareified for mere words.
Detail from the great astronomical ceiling of the ancient Egyptian tomb of Senenmut, c. 1500 BC. Note the parade of gods at the bottom, with sun disks on their heads beneath the four lunar cycles.
The domain of the line still extends just as far today-- unregulated by civilization, unfettered by geographic borders or language limitations, and potentially infinitesimal in its granularity.
Rembrandt, Three Women Looking Out a Door
Lines that have been civilized into letters and words can never return to the pagan state. Language is rule defined, so it becomes unintelligible as it approaches chaos. But the lovely, wild line of art is still at home in chaos. And as Nietzsche said, "One must still have chaos in oneself to be able to give birth to a dancing star."