I've been teaching Marshall McLuhan last week and today in my Introduction to Computational Media class. This year, for the first time in that class, I decided to assign excerpts from Laws of Media in addition to Gutenberg Galaxy and Understanding Media. In particular I wanted to expose my students to the McLuhans' tetrad of media effects. It's really the most concise, elegant characterization of media ecology, and it's darn useful too.

In case you're not familiar with it, here's a quick summary of the concept. Any medium can be described as a tetrad of effects: enhancement, obsolescence, retrieval, and reversal. These four categories can be summarized by four questions we can they ask of a medium:

Enhancement: What does the medium enhance or intensify or make possible or accelerate?
Obsolescence: What is obsolesced or pushed aside by the new medium?
Retrieval: What older, previously obsolesced ground is brought back in the new medium?
Reversal: When pushed to the limits of its potential, what earlier form does the new medium reverse into?

Here's an example, taken from Laws of Media, the tetrad for money.

Anyway, here's the bit I wanted to share with all of you. In the introduction to Laws of Media, Eric McLuhan goes to great lengths to explain that he and his father had exhastively checked and double-checked in an effort to find a case where a fifth law might be required. None were found, he reports.

Looking for materials for lecture, I found Frank Zingone's 1991 paper "Laws of Media: The Pentad and Technical Syncretism" [PDF] from McLuhan Studies 1. In the article, Zingone suggests a fifth law:

I propose a fifth operation which I believe has the same fundamentality and harmonious relations as the other categories. That new law, that fifth fundament is Syncretism, or fusion, the combining of insistent technologies into new and more fundamental unities. ... Xerox and telephone produce FAX, television and the electric range having resulted in the microwave oven, boon to simultaneous eating and viewing.

Perhaps this is old news to McLuhan scholars, but it was new to me. I'm not sure what I think of it yet. McLuhan would argue that syncretism is just a kind of extension. But Zingone has an answer for this: "Extension involves elementary set theory: tooth/finger = fork/tine, or fist/rock/arm = flint/stock/arm of the spear." In some ways, Zingone's argument is not for a new law, so much as a take on how media cohere together under the other four.