Ralph Merkle

Previous: Eric Drexler

III. The Present State of Nanotechnology

b. Ralph Merkle

   The best biographical information about **Dr. Merkle** can be obtained from his site, www.merkle.com Here is an excerpt of what he writes about himself:

"I'm also interested in molecular manufacturing (also called nanotechnology or molecular nanotechnology). The central objective of molecular manufacturing is the design, modeling, and manufacture of systems that can inexpensively fabricate most products that can be specified in molecular detail. This would include, for example, molecular logic elements connected in complex patterns to form molecular computers, molecular robotic arms or Stewart platforms (e.g., positional devices) able to position individual atoms or clusters of atoms under programmatic control (useful if we wish to make molecular computers and other molecular manufacturing systems), and a wide range of other molecular devices. A central concept for achieving low cost in molecular manufacturing is that of massive parallelism, either by self replicating manufacturing systems or convergent assembly. Such systems are today theoretical, but should revolutionize 21st century manufacturing. The marginal manufacturing costs for such systems should be quite small, although initial R&D costs might be quite significant.

I served for several years as an executive editor of the journal Nanotechnology. I chaired both the Fourth and Fifth Foresight Conferences on Molecular Nanotechnology; and won the 1998 Feynman Prize in Nanotechnology for theory...I'm also interested in **cryonics** (an Alcor Director since May 21, 1998; and chaired the fourth and fifth Alcor conferences), medical applications of nanotechnology, computational

  chemistry, reversible computing, extropians, and other areas. My wife is Carol Shaw (first female video game designer). My sister, Judith Merkle Riley, writes historical novels (1, 2, 3, 4). My father, Theodore Charles Merkle, ran Project Pluto".

Since we're interested in the social backgrounds of modern

   revolutionaries, let's look at the father of Ralph Merkle. "Project Pluto" was "a nuclear-powered cruise missile able to fly below enemy defenses". The physicist and organizer behind the project was Ted Merkle. From biography of Ted Merkle:

"Some colleagues attributed Merkle's hard-driving personality to the strain of trying to raise three kids on a teaching assistant's salary. Merkle himself boasted that, while a graduate student at Berkeley in the early 1950s, he was often reduced to feeding his family horsemeat."

So, we presume that Ted Merkle came from a lower-middle class background.

Interesting are the details of his struggle with death:

"Merkle, diagnosed as having liver cancer about the time Project Pluto was cancelled, became frustrated with what he felt was the glacial pace of medical technology. Together with Werner -- the engineer who devised an ingenious way of taking Tory's temperature -- he invented an early version of the CAT scan using the lab's computers. 'We made a topographical map of Merkle's liver,' Werner says. The patient himself watched the inexorable course of his disease with equanimity. 'He knew there was no cure,' Werner recalls. 'His interest was scientific'."

The latest contribution of Robert Merkle to nanotechnology is a 2004 book "Kinematic Self-Replicating Machines", published together with Robert Freitas. The book is a comprehensive survey of existing proposals and designs for artificial self-replicating machines. The structure of the book is of interest:

Chapter 1 explains what is self-replicating machines.

Chapter 2 describes the classical theory of machine replication, chiefly due to mathematician **John von Neumann**.

Chapters 3 and 4 give an idea of big and small machines capable of self-replication.

Chapters 5 and 6 discuss the current issues in machine replication. In particular, the authors call for a national or international scale program to coordinate the various scientific projects leading towards molecular machines.

An interesting question is "How long till nanotechnology?". Merkle writes:

*"if* we're to keep the computer hardware revolution on schedule *then* it seems we'll have to develop nanotechnology in the 2010 to 2020 time frame".

This means that nanotechnology is soon to be here.

The book exhibits a classical approach to developing a subject: 1) The question of "what is x?", i.e. initial definition of the subject. 2) Study of the history of the subject. 3) Study of the current state of the problem.

An additional a note about methodology of investigation. In his presentation "Computational Molecular Technology", Merkle proposes working "backward from the goal as well as forwards from the start". This is a methodology discovered by kids when they try to find their way through a labyrinth. It is necessary to start from the opposite ends: from the entrance to the labyrinth and from the exit. The hope is that by leading the two opposites towards each other, one will be able to meet somewhere in the middle.

Drexler, in 1992, described this methodology in science as "forward and backward chaining:

“In a forward chaining search (as the term is used in computer science), one pursues a goal by taking steps that may lead toward it, sometimes exploring blind alleys. If, however, all possible destinations are considered equally good, then there is no real goal, hence (by this loose standard) forward chaining never fails. In science, it is common to pursue experimental programs opportunistically, choosing next steps based on immediate prospects and a sense of what is interesting, important, and fundable. This process resembles forward chaining with abundant, unranked goals, and it routinely produces incremental advances in knowledge and capabilities.

“In backward chaining, one first describes a goal, then searches for intermediate situations one step removed from the goal, then for situations one step removed from those, and so forth, planning backward toward situations that are immediately accessible – that is, toward potential first steps on an implementation pathway. If there are many potential first steps, then backward chaining can be particularly attractive”.

Next: Robert Freitas