• Publications
  • Influence
Critical Transitions in Nature and Society
“voluntary animal motion” interested physicians, scholars, and philosophers throughout history for a variety of purposes such as relating “voluntary motion” to the soul and understanding medicalExpand
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Geometry from a Time Series
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The immune system, adaptation, and machine learning
We describe a dynamical model for the immune system that is based on the network hypothesis of Jerne, and is simple enough to simulate on a computer, and explore the analogy between the immune and classifier systems in detail. Expand
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Open Problems in Artificial Life
This article lists fourteen open problems in artificial life, each of which is a grand challenge requiring a major advance on a fundamental issue for its solution. Expand
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A classification of long-term evolutionary dynamics
We present empirical evidence that long-term evolutionary dynamics fall into three distinct classes, depending on whether adaptive evolutionary activity is absent (class 1), bounded (class 2), orExpand
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Two-dimensional cellular automata
A largely phenomenological study of two-dimensional cellular automata is reported. Qualitative classes of behavior similar to those in one-dimensional cellular automata are found. Growth from simpleExpand
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A Genetic Learning Algorithm for the Analysis of Complex Data
  • N. Packard
  • Mathematics, Computer Science
  • Complex Syst.
  • 1990
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The Structure of the Elementary Cellular Automata Rule Space
The structure of the elementary cellular automata rule space is investigated. Expand
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Autocatalytic replication of polymers
Abstract We construct a simplified model for the chemistry of molecules such as polypeptides or single stranded nucleic acids, whose reactions can be restricted to catalyzed cleavage andExpand
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The Nature of Life
The nature of life used to concern philosophers—think of Aristotle and Kant—but most philosophers ignore the issue today, perhaps because it seems too "scientific". At the same time, most biologistsExpand
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