_______________________________________________________________________________
Some of the key ideas included in this work
were developed in collaboration with Jackie Chappell:
https://www.birmingham.ac.uk/staff/profiles/biosciences/chappell-jackie.aspx
Notes for a 25+5 minute talk on 20th Sept 2018, at
First Symposium on Compositional Structures (SYCO 1)
School of Computer Science, University of Birmingham, UK
http://events.cs.bham.ac.uk/syco/1/
(Includes schedule of talks)
These notes present a subset of the ideas in a longer (still growing) online
paper:
http://www.cs.bham.ac.uk/research/projects/cogaff/misc/sloman-compositionality.html
http://www.cs.bham.ac.uk/research/projects/cogaff/misc/sloman-compositionality.pdf
Also available as goo.gl/hQikAJ
Or: search for: Sloman and Compositionality
AIMS
Introduction
I am also interested in how it came about that some products of evolution,
namely, humans living several thousand years ago, included forms of spatial
cognition that made possible the discoveries concerning geometry, made by
ancient mathematicians, including those in Euclid's Elements.
In part that is because many researchers don't understand what needs to be
replicated: e.g. it is not just the ability to get answers to mathematical
questions right.
As Immanuel Kant pointed out in his Critique of Pure Reason
(1781), mathematical discovery includes understanding why some things are
impossible and some things are
necessarily true, which cannot be done by collecting
statistics and computing probabilities:
Ancient mathematicians were not using what are now called modal logics, and they
were not reasoning about possible worlds:
their mathematical
discoveries included facts about
this world,
A long term aim
including some forms of special-purpose spatial cognition shared with other
species, which, in humans later provided foundations for deep mathematical
discoveries.
Key Themes:
Compositionality in individual development;
Compositionality in mechanisms produced by evolution;
Compositionality in biological information processing;
Compositionality in epigenesis;
Compositionality in biological niches;
Compositionality as a source of mathematical domains;
Discrete compositionality (as in logic, algebra, lego bricks)
vs continuous compositionality (e.g. plasticine, water, rubber bands)
vs
hybrid (discrete+continuous) compositionality
(e.g. meccano, Euclidean geometry)
Compositionality as a source of mathematical problems and competences;
Compositionality as a source of creativity in evolution;
Uses of mathematical compositionality in evolution and its products;
Compositionality in fundamental and derived construction kits;
The Meta-Morphogenesis project
Metaphysical compositionality: a source of new kinds of entity -- including
minds.
Compare the relatively recent discoveries relating to types of virtual machine,
including distributed virtual machines e.g. email systems, the World Wide Web.
NOTE:
A consequence that he played down is that in some contexts there can be a clear
sense, yet a failure of denotation, e.g.
Designers of programming languages normally try to make that impossible -- but
in so doing they restrict the generative power of the languages.
Examples include new kinds of information required to meet new control
functions.
The forms of computation required for this included new kinds of virtual
machinery, e.g. running on brains, or on insect social networks.
Compare the development by humans of
new kinds of virtual machinery since the mid 20th
century.
An example of this was the production of visual information processing.
Max Clowes and others replaced this with the idea of visual systems dealing
"syntax" in the images received and "semantics" in the interpretations of those
images.
Getting such systems to work included resolving ambiguities of grouping and
using context to resolve ambiguities of reference (does this line feature
represent a concave edge or a convex edge?)
This required perceptual systems to make use of different ontologies:
In some cases that required multi-layered ontologies, e.g. when you see a face
you may see not only the physical features but also an emotion or a mood, which
involves using an ontology of mental states.
Unfortunately some of the advances made at that time have been undermined by
recent work treating perception as if it amounted to multi-layered pattern
recognition.
The early AI researchers (e.g. Max Clowes, who introduced me to AI in 1969)
pointed out that perfectly possible images/pictures could depict impossible
scenes and therefore visual systems needed to be able to reason about
impossibility.
Preface
To introduce the talk, I presented (very briefly) two examples of impossibility
emerging from spatial composition:
-- The impossibility of closing a chain of rubber bands
http://www.cs.bham.ac.uk/research/projects/cogaff/misc/rubber-bands.html
-- The impossibility of two (non-parallel) folds of a sheet of paper meeting on
the sheet,
away from edges, with no other folds present:
http://www.cs.bham.ac.uk/research/projects/cogaff/misc/folded-paper-theorem.html
This talk is mainly about compositionality in biology, with special emphasis on
kinds of compositionality required for various types of spatial cognition.
Explaining those discovery processes and replicating them in AI systems is still
beyond the state of the art in psychology, neuroscience, and AI.
-- impossibility is not the same as 0% probability.
-- necessity is not the same as 100% probability.
How can a brain represent impossibility or necessity?
e.g. geometrical and topological facts.
Show how products of evolution that were selected because of their
practical usefulness in many contexts, were eventually transformed into more
general, less constrained, forms of information processing
Here's a subset of key-ideas relevant to my topic:
But not enough time for all:
Compositionality in biological evolution;
Evolution made closely related discoveries long before we did.
Compositionality occurs when properties of a complex structure depend, in
systematic ways, on properties of and relations between components of the
structure. E.g. the thought expressed or scene depicted by a complex sentence or
picture depends on what is expressed or depicted by the parts and how those
parts are related in the sentence or picture. Some properties (e.g. truth of a
statement, or misrepresentation in a picture) may depend also on how parts, and
the whole, are related to something external, e.g. parts of the world.
Frege implicitly introduced two parallel kinds of compositionality, insofar as
he distinguished Sinn (sense, connotation) and Bedeutung (reference,
denotation). This has important implications mentioned in the full paper.
The father of the subject of this sentence is a mathematician
The subject of the sentence fails to refer, because of infinite recursion. So
the sentence has no truth value: part of the information required to determine
the truth value does not exist. There are many such cases which are often
mis-diagnosed as generating contradictions instead of failure to have a truth
value.
http://www.cs.bham.ac.uk/research/projects/cogaff/62-80.html#1971-03
END NOTE
METAPHYSICAL COMPOSITIONALITY
One of the features of biological evolution is metaphysical creativity:
evolutionary processes can bring new kinds of entity into existence for the
first time.
At first computer scientists thought of visual mechanisms as pattern
classification mechanisms: sensor signals were segmented into items to which
labels were attached identifying recognized patterns.
--
ontologies for sensory information
--
ontologies for depicted scene contents
MODAL CONSEQUENCES
3D Visual spatial perception includes (at least) two levels of compositionality:
-- compositionality of 3D structure (scene syntax)
-- compositionality of 2D structure (projected image syntax)
Many examples are here:
http://www.cs.bham.ac.uk/research/projects/cogaff/misc/impossible.html
Here are nine blocks on a surface, shown in three possible configurations, including one in which one of the blocks is suspended above (or floats above) another block. How many other configurations are possible? How else could they be arranged? What sequences of block moves could produce the new arrangements?
Several more configurations of nine blocks are depicted below. You may or may not find one of them anomalous.
The above examples were all based on a picture by Oscar Reutersvard some time before the Penrose triangle.
The ability to detect such impossibilities depends on abilities to reason about structural relationships, not the ability to generalise from masses of examples.
In this case, and many of Escher's examples inspired by the Penrose triangle, the impossibilities arise from composition of relationships like: further, higher, more left and more right, each of which is transitive and antisymmetric. How can a biological brain represent and reason about such relationships, and understand spatial impossibility and necessity?
Young children don't all see the impossibilities that are obvious to older humans.
What has to change in their brains during development?
Jean Piaget investigated this question, but he lacked computational knowledge.
Most psychologists and neuroscientists don't understand the question.
Many current AI researchers seem to be equally ignorant.
.
.
.
.
Figure Meta above, based on ideas in Chappell & Sloman(2007), shows (crudely) how staggered gene expression can allow relatively abstract/schematic results of later gene expression to be instantiated using information gained during earlier interactions with the environment -- not necessarily using any standard form of learning. The box on the left containing "Records" is a gross oversimplification -- earlier results of interaction with the environment will feed into changes of design, e.g. development of grammars, not merely historical records.
Earlier stages of gene expression are indicated by left-most black downward arrows, and later stages by downward arrows to the right. The earlier stages are mainly determined by the genome and control not only early growth patterns but also forms of instinctive behaviour e.g. consuming nutrients or avoiding harmful entities.
Production of new species, and development of their individuals, both require use of the fundamental construction kit provided by physics and chemistry, and also increasingly many kinds of derived construction kit, discussed in more detail in Sloman(2017) and Sloman(kits), including construction kits for producing and modifying construction kits (meta-construction-kits??).
Figure 2 DCK: Derived Construction Kits
The space of possible trajectories for combining basic constituents is enormous, but routes can be shortened and search spaces shrunk by building derived construction kits (DCKs), that are able to assemble larger structures in fewer steps.
Evolution of ancient mathematical abilities
Compositionality in natural language
Intensional and extensional compositionality
Reasoning about appearance changes caused by motion
Spider creativity
More to be added!
Huge gaps between current AI and the forms of intelligence produced by biological evolution.
Evolution could not produce its intelligent animals by training them on data: the data did not exist!
I suspect our current models of computation have some deep unnoticed
limitations, though it looks as if Alan Turing began to explore ways of filling
the gap shortly before he died, in his 1952 paper:
The chemical basis of morphogenesis.
What would he have done if he had lived several decades longer?
My guess is: The Meta-Morphogenesis project
http://www.cs.bham.ac.uk/research/projects/cogaff/misc/meta-morphogenesis.html
I've provided some snapshots of its contents. Much help needed.
Can category theory -- a major theme at the workshop -- help?
Maintained by
Aaron Sloman
School of Computer Science
The University of Birmingham