Desires and Diversions

Allen Newell

Carnegie Mellon University

Wed 4, Dec 91

Styles Of Scientic LivesMaxim : To each scientific life, its own style:

And each style defines a life• A nomadic existence

• Algorithmic complexity theorists• A substantive theme

• Gordon Bell : Architectures, now multiprocessors• A sequence of strategic objectives

• Werner Reichert of the Max Planck Institute, Tubingen• A scientific idea takes five years to bring to fruition

• To work on interesting problems• Their number is legion

• Whatever next seems publishable• Publish or perish as the operative law of scientific life• They shall be nameless

• A single ultimate scientific question• Herb Simon : Bounded rationality• Raj Reddy : Speech recognition• Myself : The nature of the human mind

My Style : The Pursuit of a Single Desire The Nature of the Human Mind

Maxim : Science is in the details• What the question is

• How can mind occur in the physical universe?• An answer must have the details : Generalities won’t do

• What the question is not• What is the nature of intelligence? (the AI question)• How does bounded rationality explain? (the Simon question)• The mind-body problem (the philosophy question)• What is the nature of the brain? (the neuroscience question)

• An ultimate scientific question : A select company• Why does the universe exist?• When did the universe start?• What is the nature of life?• What is the origin of life?• Why is evolution so stable?• A grand unified theory of the universe• To see an atom

When Does a Scientific Life Start?Maxim : The scientific problem chooses you, you

don’t choose it• Not at age 17 : When I wanted to be a forest ranger• Not at age 19 : When I wanted to be “a scientist”• Not at age 22 : When I wanted to be an optical engineer• Not at age 27 : When I wanted to be an organizational scientist• But at age 27.7 : On a Fri afternoon in mid Nov 1954

• A conversion experience : The Oliver Selfridge visit• A pattern-recognition system on the Whirlwind MTC

• The insight : Computers can do any complex processing• But understanding the mind was already determined

• This was just before the great burst of 1956-58• 1956 : The Logic Theorist (LT) occurred• 1956 : List processing occurred (IPL)• 1957 : GPS occurred• 1958 : The chess program occurred

• Nothing in 1954 presaged the imminent arrival of this burst

Diversions : And Their Uses #1

Maxim : Diversions occur, make them count• Salvage what is possible for the main goal

• Gordon Bell and Computer Structures (1968-72)• Diversion : To help a colleague write a book• Uses : PMS and ISP were themselves a contribution• Salvage : The concept of the architecture

• Raj Reddy and Speech Understanding Systems (1970-76)• Diversion: Help the DARPA community and to help Raj• Uses : Speech Understanding Program a major success• Salvage: Only understanding of sensory processing

Diversions : And Their Uses #2

• Stu Card, Tom Moran and The Psychology of HCI (1973-83)• Diversion: Something on the West Coast• Uses: Routine cognitive skill and GOMS, established

HCI• Salvage: Model Human processor as a unified theory

• Don McCracken, George Robertson and ZOG (1973-84)• Diversion: Two great grad students and L*• Uses: Helped start hypermedia, a major application• Salvage: There are no short cuts to intelligence

• Points of note• The diversions were all for social reasons• They lasted a “long” time• But always came back to the basic scientific goal

Failures : And Their Uses #1

Maxim : Embrace failure as part of success But use it for the main goal• Merlin : With Jim Moore, Richard Young (1968-74)

• Idea : All Thought was seeing X as a Y, further specified Frames, attached procedures, general mapping, indefinite context dependence, automatic compilation

• Failure : We simply couldn’t make it work

• Uses : It died and had no uses at all • Did “not” learn that the idea was wrong

• Salvage : Need a global view, not a worm’s-eye view

Failures : And Their Uses #2

• Instructable Production System Project (1976-1979)• With Lanny Forgy, John McDermott, Mike Rychener, John Laird,

Paul Rosenbloom

• Idea : Grow a production system by external means• Obtain a large production system (1000 productions)

• Failure : Never got off the ground, never produced a thing• Uses : Ops5 (Forgy), R1/XCON (McDermott), Universal

Weak Method (Laird), Eng. AI (Rychener)• Salvage : Launched Soar (Laird, Newell, Rosenbloom)

• Need default methods (universal weak method)• Need organization of “flat” production systems• Solution was problem spaces

• Points of note• Failures can last a long time

Failures : And Their Uses #3

• Chess language : With Bob Ramey (1962-63)• L* : With Don McCracken, George Robertson

(1969-74)• The nature of design : With Peter Freeman (1969-

71)• Automatic protocol analysis : With Don Waterman

(1970-73)• Problem generation : With Ramani (1973)• Psychology of programming : With Reuven Brooks

(1970-75)

Successes : And Abandoned Opportunity #1

Maxim : Solve whatever problems must be solvedBut do not be seduced by them

• List processing (1956-64)• Ideas : Lists, dynamic resource allocation, date types, recursion,

generators (streams)

• Abandon : Not participate in the list-processing literature

• Hashing : A dinner with Marvin Minsky (July 1961)• Ideas : Associative access in random-access memories

• Abandon : Wrote one unpublished paper

• Protocol Analysis (1960-72)• Ideas : Using sequential, NL content data for theory

• Re-establishment of “introspection” as legitimate• Abandon : Not follow up with methodological studies

• But tried automatic protocol analysis (failed)

Successes : And Abandoned Opportunity #2

• Efficiency of productions systems (1976-)

• Ideas : Rete algorithm, fine-grained parallelism, affect set, expensive chunks, unique attributes

• Not yet abandon : Because not yet usefully solved

• Points of note

• Success can last a long time too• But never (ultimately) diverted

• A long life helps to copy with the diversions and seductions

Successes : And Their Cultivation

• Maxim : Preserve the insight and deepen it• Deep ideas transform themselves beyond imagining

• Maxim : Deep scientific ideas are exceedingly simple• Others usually see them as trivial

• List processing (1956)• Search (1956)

• Symbols (1960)

• Problem spaces (1965)

• Weak methods (1969)

• Production systems (1972)

• Knowledge level (1980)

• Chunking (1981)

• Impasses (universal subgoaling) (1983)

A Deep Idea Transformed

The Problem Space• The idea : So trivial as to be uninteresting to most folk

• A problem space is a set of states and a set of operators from state to state. A problem is to go from the initial state to a desired state by applying a sequence of the operators.

1. The search space for heuristic combinatorial search (1957)2. The space in which all problem solving occurs (1965)3. The deliberately limited arena in which to solve a task

(1957?)4. The area in which “all” task accomplishment occurs (1979)5. Multiple spaces formed by lack of knowledge (1983)6. A least-commitment program control construct (1987)7. A device for the formulation of tasks out of nothing (1990)8. A device for general error recovery (199?)

The problem space is “all” of these simultaneously

Deep Ideas Transformed

• Brief treatment of the others• List processing (1956)

• Lists ->dynamic resource allocation ->attribute-values ->symbol systems ->production systems

• Search (1957)• A method -> “the” method ->the weak methods ->UWM ->only one

search method (MPD)(?)• Symbols (1960)• Problem space (1965)• Weak methods (1969)

• “weak” methods ->search methods ->universal weak method -> problem spaces

• Production systems (1972)• Operators ->recognition (association) memory

• Knowledge level (1980)• A view ->operational concept

• Chunking (1981)• Impasses (universal subgoaling) (1983)

Choosing the Final Project• Maxim : Choose a final project to outlast you• Maxim : Everything must wait until its time

• Science is the art of the possible• Soar seems like a typical final project• Look at what has to be done

• Have the right “architecture”• Learn continuously from “experience”• Communicate with the external world “easily”• Learn continuously from its “environment”• Live a “long” time• Embody “all” its tasks simultaneously• Become “very large” : 10^5 to10^6 associations• Have a sense of “history and place”• Have a system with a sense of “self”• Learn from a “social community”It will surely outlast me!

• But Soar is not a final project : Simply a “next project”• Chosen in 1983 (at 56)• Choice was strategic : Aimed right at main goal

• Commitment comes from confluence of indications• Problem spaces + productions, universal weak method, impasses,

chunking, human cognitive architecture

Maxims for a Dedicated Scientific Life Maxim : To each scientific style, its own maxims

Maxims occur throughout the talk: But not every one• to work with results of field X, must be a professional in X

• Cognitive psychology, linguistics, neuropsychology• We are all flawed : We all carry our burden of incapacities

• Know them like the back of your hand and don’t fight them• Mathematics as an example

• There is no substitute for working hard : very hard.• The law of competition at the margin of excellence

• New things get started by evolution or chance, not design• The “next problem” or what falls on the prepared mind

• A scientist is a transducer from nature to theory• seek out nature and listen to her!• My version of Herb Simon’s “have a secret weapon”

• The science is in the technique : All else is commentary• What lives is what your scientific descendents must use to solve

their problems• Do your philosophy on the banquet circuit• Symbol systems, Twenty questions, The knowledge level

Desires and Diversions

Allen Newell

4 Dec 91

What happens with a whole scientific career? Mine isn’t over, but it’s already forty years long. What shape and even purpose can be given to such a endeavor? Like all things human, the answers are diverse : there are many styles of scientific lives. The one I know best, of course, is my own. it hardly seems unique to me, but it does typify a definite style. I will tell some of the story of my own total scientific endeavor, and try to tell it to shed light on how to live a science.