1989*Alternate Realities*.*Paradigms Lost*. 19891991*Searching for Certainty*.*Five Golden Rules: great theories of 20th century mathematics---and why they matter*. 1996*Boundaries and Barriers*. 1996, with Anders Karlqvist*Would-Be Worlds*. 1997- [
*The Cambridge Quintet*.] 1998 *Unconventional Models of Computation, UMC'98*. 1998, with Cristian S. Calude, Michael J. Dinneen1999, with Anders Karlqvist*Mission to Abisko*.*Five More Golden Rules*. 2000*Paradigms Regained*. 2000

- The outer limits: in search of the "unknowable" in science. 1996. (In
*Boundaries and Barriers*) -
*The Cambridge Quintet*: the chronicle of an experiment in 'scientific fiction'. 1999. (In)*Mission to Abisko*

Are there scientific problems that cannot be solved?
Mathematics is riddled with such problems, but can we pose analogous questions *outside* of mathematics?
Does nature itself impose fundamental limits on our knowledge of the universe?
Despite the work of some of the greatest minds of the twentieth century, no one really knows.

In May 1995 this profound and far-reaching concern brought together
a small but select group of scientists in a remote scientific outpost
in Abisko, Sweden, a village far north of the Arctic Circle.
*Boundaries and Barriers* captures the spirit—and the content—of the talks given at the meeting.
Included are contributions by John Barrow on the limits of science,
John Casti on the search for the “unknowable” in science,
James Hartle on quantum cosmology,
Harold Morowitz on complexity and epistemology,
and six more fascinating chapters that illuminate the possible limits
to what we can know by using the tools of science.
The issues discussed here challenge the very foundations of science,
but the conclusions are optimistic.
When the dust clears, science remains standing—our best bet for understanding the way the world works.

- • John D. Barrow.
**Limits of science**. 1996 - • John L. Casti.
**The outer limits: in search of the "unknowable" in science**. 1996 - • Newton C. A. da Costa, Francisco Antonio Doria.
**Variations on an original theme**. 1996 - • Walter Fontana, Leo W. Buss.
**The barrier of objects: from dynamical systems to bounded organizations**. 1996 - • James B. Hartle.
**Scientific knowledge from the perspective of quantum cosmology**. 1996 - • Piet Hut.
**Structuring reality: the role of limits**. 1996 - • Harold J. Morowitz.
**Complexity and epistemology**. 1996 - • Robert Rosen.
**On the limitiations of scientific knowledge**. 1996 - • Karl Svozil.
**Undecidability everywhere?**. 1996 - • Joseph F. Traub.
**On reality and models**. 1996

- • Martyn Amos, Steve Wilson, David A. Hodgson, Gerald Owenson, Alan Gibbons.
**Practical Implementation of DNA Computations**. 1998 - • Artur Ekert, Chiara Macchiavello.
**An Overview of Quantum Computing**. 1998 - • H. Jeff Kimble.
**Implementing Quantum Logic and Communication via Cavity QED**. 1998 - • Seth Lloyd.
**Unconventional Quantum Computing Devices**. 1998 - • Cristopher Moore.
**Finite-Dimensional Analog Computers: Flows, Maps, and Recurrent Neural Networks**. 1998 - • John H. Reif.
**Paradigms for Biomolecular Computation**. 1998 - • Arto Salomaa.
**Turing, Watson-Crick and Lindenmayer. Aspects of DNA Complementarity**. 1998 - • Gordon Alford.
**Explicitly Constructing Universal Extended H Systems**. 1998 - • Mark H. Butler, Raymond C. Paton, Paul H. Leng.
**Unconventional Approaches for Biologically Inspired Computing**. 1998 - • Elena Calude, Marjo Lipponen.
**Deterministic Incomplete Automata: Simulation, Universality and Complementarity**. 1998 - • B. Jack Copeland.
**Even Turing Machines Can Compute Uncomputable Functions**. 1998 - • Michael Frank, Thomas F. Knight Jr, Norman H. Margolus.
**Reversibility in Optimally Scalable Computer Architectures**. 1998 - • Michael Frank, Carlin Vieri, M. Josephine Ammer, Nicole Love, Norman H. Margolus, Thomas F. Knight Jr.
**A Scalable Reversible Computer in Silicon**. 1998 - • Rudolf Freund, Valeria Mihalache.
**Molecular Computations on Circular and Linear Strings**. 1998 - • Yuzhen Ge, Layne T. Watson, Emmanuel G. Collins Jr..
**Genetic Algorithms for Optimization on a Quantum Computer**. 1998 - • Karl Gustafson.
**Ergodic Learning Algorithms**. 1998 - • Peter Herding.
**Embedding Cellular Automata into Reversible Ones**. 1998 - • Thomas F. Knight Jr, Gerald Jay Sussman.
**Cellular Gate Technology**. 1998 - • Alexandru Mateescu.
**Splicing on Routes: a Framework of DNA Computation**. 1998 - • Hideaki Matsueda.
**Spatiotemporal Evolution of Quantum Entangled Pure States in Quantum Computing Solid Block Circuits**. 1998 - • Lakshmi Narayanaswamy, Peter M. Kogge.
**Combinators and Processing-In-Memory: An Unconventional Basis for Avoiding the Memory Wall**. 1998 - • Mitsunori Ogihara, Animesh Ray.
**The Minimum DNA Computation Model and Its Computational Power**. 1998 - • Gheorghe Paun.
**Distributed Architectures in DNA Computing Based on Splicing: Limiting the Size of Components**. 1998 - • Boris S. Pavlov, Gary Roach, Adil Yafyasov.
**Resonance Scattering and Design of Quantum Gates**. 1998 - • Yuzuru Sato, Makoto Taiji, Takashi Ikegami.
**Self-Similar Sets as Satisfiable Boolean Expressions**. 1998 - • Karl Svozil.
**The Church-Turing Thesis as a Guiding Principle for Physics**. 1998 - • Carlin Vieri, M. Josephine Ammer, Amory Wakefield, Lars "Johnny" Svensson, William Athas, Thomas F. Knight Jr.
**Designing Reversible Memory**. 1998 - • Herbert Wiklicky.
**Quantitative Computation by Hilbert Machines**. 1998

The 1997 annual Abisko seminar brought together scientists and science fiction writers to discuss the use and importance of narrative in science. This collects together some of the participants' papers. Most are interesting, but maybe not quite long enough to develop their ideas in full. I suspect the conference itself was quite fun.

All the participants agree that story-telling is important in how we understand science, at whatever level. The fiction writers also reckon that SF is important for insulating us from surprises when new technology appears in our lives, for allowing us to have already had the ethical debates in fiction. However, Paul McAuley points out that the media and the public tend to go for the emotional horror slant, rather than the more rational SFnal perspective -- so maybe SF insulates only SF fans?

- • John D. Barrow.
**The Analogy of Nature**. 1999 - Scientists use analogies to describe nature; this may be limiting what theories they can come up with. There may be no analogies for deep theories.
- • Greg Bear.
**Proving the Dream**. 1999 - How science fiction and science work together to change the future
- • Gregory Benford.
**Beyond this Horizon: envisioning the next century, or stories of our (preventable?) future(s)**. 1999 - The 20th century saw incredible advances due to physics; the 21st will see even more, due to biology.
- • John L. Casti.
. 1999*The Cambridge Quintet*: the chronicle of an experiment in 'scientific fiction' - The reasons for using 'scientific fiction' to explain science
- • Jack Cohen.
**Becoming Maureen -- a story of development**. 1999 - The importance, and difficulty, of understanding
*process*. [I felt I was coming in at the second part of some larger story.] - • Per-A. Johansson.
**Algorithmic and Asthetic Storytelling: alternative approaches to imagination and reality**. 1999 - Our current scientific, or "algorithmic" style of story
telling doesn't cover everything -- we still need stories of how to live
our lives. [Unfortunately, from my point of view, Johansson has a god in
these stories. I do feel we need these higher level stories, but I
prefer ones we
*explicitly*construct for ourselves, rather than ones attempting to discern some non-existent Platonic ideal.] - • Kjell Jonsson.
**Einstein at the Amusement Park: the public story of relativity in Swedish culture**. 1999 - Einstein's theories of relativity were not well-received in Sweden, neither by the Nobel Committee, nor by the scientific community
- • Anders Karlqvist.
**Telling Science**. 1999 - There are at least four different levels for communicating science, depending on the audience -- and all four are valuable
- • Paul J. McAuley.
**Frankenstein's Daughters**. 1999 - SF looks at scientific advances neutrally -- story outcomes may be good or bad. Horror starts with the emotional "yuk" factor, and it's always bad. And now science is advancing so fast that we are running out of SF stories to prepare us for the future.
- • Larry Niven.
**Mission to Abisko**. 1999 - A personal journal of his last-minute attendance at the conference
- • Ian Stewart.
**Secret Narratives of Mathematics**. 1999 - A plea that mathematicians pay attention to the narrative structure of their proofs, telling a compelling, understandable "story", rather than just concentrating on the "syntax"

- The Alexander Polynomial: knot theory
- The Hopf Bifurcation Theorem: dynamical system theory
- The Kalman Filter: control theory
- The Hahn-Banach Theorem: functional analysis
- The Shannon Coding Theorem: information theory