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Multicellular Life as a Metaphor for the Future of Computing

Computers collaborate in the Internet much the way cells collaborate in multicellular organisms. But cells do it better! What are the parallels and what can we learn from them?

In the last twenty or thirty years, computers have become vastly more capable and the role computers play in the world has changed dramatically. During that time, our understanding of biology has also, and not coincidentally, grown immensely and changed qualitatively. Where once we investigated genes, we now look at and compare whole genomes. Where once we laboriously investigated individual proteins, we now look at whole proteomes across multiple species. The dramatic development of computing has done much to enable the dramatic developments in cellular and molecular biology. Neither genomics nor proteomics could exist in their present forms without computers. And computer analysis, simulation and modeling is required to understand the complex interactions between the various elements in biological systems. Computing, too, benefits, even if in less quantifiable ways, from our increased understanding of biology. The way cells and organisms and whole ecologies collaborate provides examples and metaphors for the advances in the way we use distributed computing.

As recently as 1990, most computers operated independently from each other. A few exchanged email or used FTP tools to transfer files. Some collaborated in client-server relationships with internal corporate networks, banking systems or airline reservation systems. In 1992 a tiny number of computers -- mostly in universities or research labs -- could connect to the nascent Web. Nonetheless, most computing was done with single disconnected computers.

Today, only twenty years later, an isolated computer is something of an oddity. At least a billion computers exchange information at Internet speeds. Google, Amazon, Yahoo and Baidu (China's Google equivalent) require tens or even hundreds of thousands of computers collaborating together to provide services on our laptops or iPhones that we already take for granted. The digital world inexorably becomes complex beyond our comprehension. But there is no going back.

Bigger groups of computers collaborate in ever more complicated and less transparent ways as programmers and computing architects think of new ways to exploit digital collaboration and try to reduce the hazards of viruses, worms, botnets, and all sorts of other malware. At the same time, cyber criminals and other digital predators devise new tricks to exploit these complex interactions for their own purposes.

The evolution of computing is similar to the evolution of other complex systems -- biological, social, ecological, and economic systems. In each of these domains, the elements become increasingly more specialized and sophisticated, and they interact with each other in ever more complex ways. Such similarities between biology and computing are not coincidental.

The organizing principles of multicellular biological systems suggest architectural principles that multicellular computing can mimic to tame the spiraling problems of complexity and out-of-control interactions in the Internet.

This website explores four fundamental architectural principles that enabled the transition from single-cell life to multicellular life and are already used in many computing systems. They are:

• Specialization - Multicellular systems support much richer functionality than single cell and single computer systems. They do it by the collaboration between specialized cells. There are, for example, about 250 specialized types of cells in humans. Unspecialized cells don't "play well with others," hence are dangerous to any multicellular organism. Specialization in computing is important as well. We are finding that unspecialized general-purpose computers, especially unprotected PCs, are increasingly dangerous to multicellular computing systems.
• Messaging -To cooperate, cells or computers must communicate safely with one another. The "meaning" of cell-to-cell messages must be determined by the receiving cell, not the sender. To that end, cells communicate with each other via messenger molecules, never DNA. Similarly, communication between computers in multicellular systems relies increasingly upon message passing. Here again, the receiver not the sender determines the meaning of the messages. It is dangerous for computers to transfer code from one machine to another because code predetermines the resulting behavior of the receiving machine, and all too often contains malware. Code endangers the health of the receiving machine and hence the larger system of which it is a part.
• Stigmergy - Messages orchestrate cooperation in real-time. Longer term or more persistent collaboration requires longer-lived messages that can be deposited in some structure where they can be later encountered by others. This sort of messaging has become known if the field of biology as stigmergy. Analogously, stigmergy in computing systems is supported by persistent external data, e.g., in databases, and network connectivity structures. Persistent data are especially important for organizing cooperative computing in the Internet.
• Programmed cell death (apoptosis) - Despite all precautions, cells and computers do go awry or outlive their usefulness, Every healthy cell in a multicellular organism is programmed to commit suicide if necessary for the best interest of the organism as a whole. Cells that are infected by viruses or become cancerous often kill themselves. We are only recently learning the importance of sacrificing compromised computers for the health of the whole multicellular computing system.

These four principles are not independent; they are deeply intertwined both in life and in computing.

This site explores these principles in considerable detail -- more detail than most readers would want to absorb in one sitting. It presents each principle in its biological context and describes its benefits both for multicellular life and for computing.

If you are impatient, you might want to skip right to the end of the story and read the conclusions. However, as with many a mystery novel, reading the last few pages will tell you who-done-it without telling you the most interesting part...why.  The conclusions may well not make much sense without seeing how we get there.

The site map or the link panels on the left of each page can help navigate to the various pages in an order that helps make sense of the story.