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Emergence PITP workshop May 15-18, 2005 Vancouver, BC. Semantic Transmission and the Emergent Mind Antony Crofts Department of Biochemistry University of Illinois at Urbana-Champaign.

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PITP workshop

May 15-18, 2005Vancouver, BC

Semantic Transmission

and the Emergent Mind

Antony Crofts

Department of Biochemistry

University of Illinois at Urbana-Champaign

A more complete account, with links, but without pictures is available at



(At this point, the audience was asked to close their eyes; the speaker then said “We are such stuff as dreams are made of, and our little life is rounded with a sleep”. The audience was then asked to consider what had come into their minds on hearing this sentence.

The speaker offered several suggestions, and pointed out that even those who were able to identify the quotation (Prospero’s speech to Miranda and Ferdinand, Act IV, The Tempest) had not noticed the right answer.

Nothing enters the mind under these conditions, - but something does enter the ear. The sound waves are purely physical, and the meaning that becomes apparent in the mind is the consequences of a hierarchical series of translational machineries and interpretational filters, eventually triggering a more sophisticated set of associations to pre-existing mind entities.

The speaker then suggested that this odd property of the mind was interesting, and promised to explain the pathway through which his own interest was aroused.)


Quantifying the energetics of the biosphere

The earth is in steady-state, so incoming energy is matched by outgoing energy. The Second Law is satisfied by the larger number of quanta of lower energy going out.

To the extent that the biosphere is in steady-state, its effects are subsumed under existing terms.

Since the emergence of modern man, civilization has contributed an increasing additional effect, - civilization, - including an increased informational content, and direct environmental effects.

How can we bring these effects into our accounting of energy fluxes?


50% arriving at surface

33% in growing season

20% intercepted by leaves

20% lost by reflection

50% photosynthetically inactive (wrong color)

30% conversion efficiency

40% lost to maintenance

0.5% Net Primary Productivity (NPP). This is ~10 × total world energy consumption

Based on

Life is sustained by a relatively small fraction of the energy from the sun, - the 0.5% yield of net photosynthetic product that is recycled as heat through animal consumption, and bacterial and fungal biodegradation.

Thermal loss is delayed by “latent heat” effects: wind, waves, currents, hydrological cycle.

Biosphere can be thought of as a latent heat effect. Dissipation is delayed, because the photochemical conversion in photosynthesis is stored through coupled chemical reactions.


The biosphere

  • The biosphere - all the living forms on the planet (for the physicist, - a thin layer of negentropic slime over the surface). Human kind is naturally part of the biosphere, operating through the same mechanisms as other life forms. Basic biochemical mechanisms are the same throughout living forms from bacteria on up.
  • The energy conversion processes through which the biosphere is maintained are well-understood. Photosynthesis uses energy from the sun to synthesize complex molecules. These in turn provide the energy used to sustain the rest of the biosphere through respiration and fermentation. Reactions are coupled so that energy drops are matched, the dissipation functions are shallow, and fluxes are highly controlled.

Your biosphere at work

The seasonal fluctuation of NPP over two years (see bottom scale).

The biological and solar flux aspects can all, in principle, be accounted for.

What about the information content of “civilization”?

Movie from Earth Observatory (


Information Content – three different meanings

  • Three different usages of the term “ information content”:
    • Order in the system, - classical entropy, usually used in the context of data encoding, transmission, translation, etc., and their thermodynamic costs.
    • Shannon’s Informational Entropy (equation below), which is useful in comparing information encoded in different formats.
  • The constant K is arbitrary. Boltzmann’s treatment of entropy was developed via a similar equation, but the relation to physical states was explicit, through kB. The two functions are obviously related, but Shannon entropy is useful mainly because it allows quantification of coding elements without reference to their physical state. (A similar probability function was first proposed by de Moivre in “The Doctrine of Chances”, 1718)
  • c) Semantic content. Shannon noted the distinction between “engineering aspects” as covered by a) and b), and the semantic content, - the “meaning of the message”. No obvious way to relate semantic content to formal thermodynamics.

Three suggestions to define properties of semantic content

  • The semantic content of a message adds no additional thermodynamic burden over that due to the “engineering aspects”.
  • The semantic content has a value only in a particular context.
  • The meaning only becomes apparent on translation and/or interpretation.

Two avenues for information transmission in the biosphere

  • The forms of living things (the phenotype of each) are defined by the information in DNA (the genotype). All living things have this avenue for semantic transnission.
    • Transmission of information between generations is a copying function.
    • Contemporary life forms all have a semantic heritage through DNA going back to the same common ancestor, - a duration of the same length, ~3.5 billion years. If there were a thermodynamic cost of semantic content, it would be amortized over this 3.5 billion year period.
    • You are the result of a translational machinery with hierarchical levels of increasing combinatorial complexity: (DNA→protein→cells→tissues→you).
  • For human kind, an additional channel for semantic transmission is provided by the extra-chromosomal cultural heritage, – the collective stored output of human consciousness, - the whole apparatus of civilization.

(4 bases → 20 aminoacids → 30,000 proteins → metabolism, structure, control, recognition )

(~128 symbols → 50,000 words (educated vocabulary), numbers, etc.→grammar, syntax → an infinity of ideas)







  • Interesting issues arising from the properties of semantic transmission
  • Semantic content of the cultural heritage has the same properties as that transferred through DNA, - the semantic content imposes no additional thermodynamic burden over that of data storage and transmission mechanisms, it has a value only in a particular context, and the meaning of the message is apparent only through translation and/or interpretation.
  • These properties demand complementary properties of the human mind. All input to the mind is via physicochemical detectors (the five senses). Before anything has meaning it has to go through a hierarchical series of translational and interpretational filters. We cannot interpret information for which we lack the translational machinery.

(At this point, we recall the experiment with which the lecture started)

Where did the mind come from?



Evolution, behavior, time, and the emergence of mind

    • Three components, - the biological apparatus, the individual mind, civilization.
    • All living things show behavior, - they respond to the environment. The response represents a temporal sequence and requires an awareness of time, - chronognosis.
      • Anticipation of changes in the environment has an evolutionary advantage.
      • One line of evolution has been towards the exploitation of temporal awareness through the development of movement, and a sophisticated sensory apparatus, to increase the chronognostic range – animals, and eventually, human kind.
      • Plants also show chronognosis, - diurnal and seasonal variations in form and metabolism in anticipation of the availability of light, temperature, water, etc.
      • Up until ~150,000 years ago, all behavior was determined by the biological form of the phenotype, - transmission of semantic information through DNA (genotype).
    • 2 and 3. With the evolution of modern man, the development of a sophisticated vocal apparatus, and the extension of certain properties of the brain, came the development of consciousness, language, mind, and eventually of civilization.

Evolution of the individual mind

The nature of mind as a translational machinery for physicochemical input means we can know only what we are already equipped to “understand”.

Our conception of reality, starts in the womb as a blank slate, and expands as our physical contact with the world makes possible an iterative process of verification and reformulation. The newborn mind evolves to the adult mind through an extended learning process.

Education recapitulates civilization

We are thinking machines. Each individual mind accumulates a unique set of perceptual images, and can re-order and re-correlate these to generate new world models, - to create new ideas. Acquisition of language allows us to interpret more abstract semantic content. Within the limits of our interpretational machinery, we can correlate incoming “ideas” with our existing world model, reconfigure them, and transmit them in “conversations”. This individual “mutation” of ideas is what allows our cultural heritage to evolve, - what gives it life.

The obvious social context brings in a third level at which evolution occurs.

New ideas are subject to “selection pressure” from social peer groups



  • At the DNA level:
    • Conservation of useful characteristics requires faithful reproduction of the semantic message in DNA.
    • Evolution requires new forms that compete. The mechanisms of evolution work on the variations among species to select those fittest for survival.
    • The copying machinery therefore has to be imperfect – random mutations that are not perfectly repaired.
    • Selection through survival of the fittest leads to more “advanced” forms – better able to garner the thermodynamic potential.
    • Competition occurs between and within populations of species, but works at the individual level. The semantic content of DNA only has meaning in this context.
    • The interplay within populations, between populations, and with the physical and chemical environment, through feedback on the genome, means that the informational context within an ecology is extremely complex.

Evolution (continued)

  • Similar mechanisms work in the evolution of societies.
    • The cultural heritage of a civilization is sustained through the faithful transmission of its semantic content between individuals and over generations, through education and archival storage.
    • The ability of the individual mind to “mutate” ideas introduces a variability through which evolutionary pressures can play a selective role.
    • The exchange between the individual and the wider society harboring a civilization introduces an inevitable social context. We think within our cultural heritage, - “sorting algorithms” learnt in education. Our peers can only deal with our “conversations” if our ideas are within an agreed common frame of reference, - we have to share similar “sorting algorithms”.
    • The two-way semantic traffic of such “conversations” is the basis of our education, teaching, society, etc., and the source of all change in the cultural heritage.

70,000 years ago

Emergence of civilization

Babylonian tablet world map, 600 B.C.

Pythagorean integer triples, 1800-1650 BC

Catal Hoyuk town map Turkey, c. 6200 BC

Stonehenge, 2800 – 1800 BC

1543 AD

Geometric theorems in Ahmes papyrus, 1850 BC

Map of the world, c. 150 AD, reconstructed from Ptolemy’s work

Sophisticated language, tool making, semantic abstraction


Lascaux cave drawings

Invention of archival data storage

(See here for links to sources)

Chinese 1500 BC to now



early civilization




Emergence of the mind

  • The evolution of the modern human mind arises from the extension of behavior into a supra-phenotypical range, and echoes the emergence of civilization.
    • Social systems
    • Language
    • Conscription of inanimate matter to extend behavior, - tool making
    • Abstract representation
    • Agriculture, allowing extensive settlements
    • Number systems
    • Writing
    • Monumental calendars
    • Division of labor and social stratification
    • Formal education
  • The present adult mind depends on the combined efforts of thousands of prior generations in establishing the external semantic heritage that provides the base and framework of our knowledge. Rather than “cogito ergo sum” , we should say “cogito ergo sumus”, - the difference is us.
  • The phenotype has probably not changed significantly over this period. The mind that shaped the art of Lascaux was not inferior, but educated to a different context.

The remarkable increase since the 15th century seems to be progressing exponentially (slope log plot ~3.85).

The importance of Western civilization as seen through the increase in chronognostic range as the biosphere has evolved

We could use many different indicators of civilization on our y-axis

Many contributions:

Printing, exploration

Renaissance, reformation, humanism

Copernican revolution

Emergence of rationality from constraints of dogma.

Where is this headed? Uncertain, because of downside, - environmental damage.

There are many instances of the demise of civilizations, each an example of the sort of survival test through which civilizations are filtered. Civilizations evolve and adapt, or perish.


Philosophical parallels and epistemological implications

  • The picture of the emergence of mind required by recognition of the thermodynamic inconsequence of semantic content is an evolutionary one - the mind emerged as a translational machinery of increasing complexity, equipped to interpret the thermodynamic world, and the cultural heritage. The addition of a second channel for semantic heritage provided an obvious advantage in development of skills to extend our exploitation of thermodynamic potential in the physical world.
  • Popper’s Three World model:
  • World 1 – the physical world; World 2 – the human mind; World 3 – the extrasomatic cultural heritage, and its evolution.
  • Popper introduced the evolutionary perspective – a model of the mind that placed its evolution in a biological context, and considered the nature of the traffic between the three worlds in an epistemological framework.
  • 2. Campbell’s evolutionary epistemology
  • Dawkin’s memes – insubstantial, infective mental agents. The parallel to viral infection (in “Viruses of the Mind”) seems far fetched.
  • What about the wider philosophical context?

Epistemological perspective

Fundamentalist religions

Gödel’s incompleteness theorems

Deterministic science

Classical biology

Logical positivists


Problems of inductive logic

Darwin and evolution


Quantum theory



From the limitations of inductive reasoning, it is apparent that there are many proposition for which we cannot establish “truth”. Different philosophical strategies for dealing with this.

Crisis of certainty

Wittgenstein II - language games, philosophy as therapy

Scientific realism

(Pictures mostly from MacTutor, otherwise individual websites)

Popper – test hypotheses against reality

Kuhn -science as paradigms

Bloor, - science as sociology, - truth is relative

Richard Rorty -

pragmatism, antirealist


From Boswell’s Life of Johnson:

“After we came out of the church, we stood talking for some time together of Bishop Berkeley\'s ingenious sophistry to prove the nonexistence of matter, and that every thing in the universe is merely ideal. I observed, that though we are satisfied his doctrine is not true, it is impossible to refute it. I never shall forget the alacrity with which Johnson answered, striking his foot with mighty force against a large stone, till he rebounded from it – ‘I refute it thus.’”


Accept the idea that we can never establish the truth of a hypothesis

Replace the goal of verifiability by that of falsification. A hypothesis is useful only if it can be tested. We can demonstrate that a hypothesis is not in accord with the measurable properties of an external reality.

Evolution in the social context of peer groups will determine the survival of hypotheses that continue to withstand the falsification test.

Occam’s razor (simplicity test)

(Einstein’s interpretation - “Things should be kept as simple as possible, but not simpler”)

Importance of paradox

(Chesterton’s definition - “Truth standing on her head to get attention”)

Of course, Johnson did not refute Berkeley’s ideas by this action. Nevertheless .…


Nemani et al. (2003) Science 300, 1560-1563

World population

Constraints on NPP (above)

World population (top right)

“Civilization” (excess energy, from light usage at night) (bottom right)

Composite picture of the earth at night from satellite data

What determines the competitive success of a civilization?


Organized social structures are necessarily highly ordered, and hence inherently unstable.

  • The appearance of stability comes from the development of political, social, economic, technical, and philosophical tools that make possible the continued maintenance, renewal and evolution of these institutions through the input of work.
  • The continuous application of human endeavor needed to maintain the stability of a complex society is best served through the willing participation of its members. “Willingness” can be engendered through different mechanisms; - fear, religious or totalitarian fervor, bribery and greed, “informed consent”, etc.
  • The most successful exploitation of physical and intellectual resources has occurred in the context of democratic societies. The feedback loops between government and the people, and freedom to choose, open up possibilities for error correction that seem to have a longer term advantage.
  • The freedom to express ideas has an obvious evolutionary advantage. If the sorting algorithms condoned by society limit ideas to those that conform to “scripture”, Quran, “the party line”, etc., stagnation can be guaranteed.
  • Our extensions of the limits of experience and of our chronognostic range are all part and parcel of the same thing, - the evolution of the biosphere to take advantage of the thermodynamic opportunities available through refinement of the semantic heritage, and increased combinatorial complexity.


Philosophical discussion must be framed in the context of an evolving culture, and the mutability of ideas in individual minds.

If we want to get our ideas across to a wider audience, we must bear in mind the limitations of the translational machineries in different minds (avoid abstruse technical terms if possible).

We need to ensure through all democratic means at our disposal that our society continues to allow free expression of ideas without the constraints of dogma.

We must take responsibility for our future by addressing the effects arising from our exploitation of the thermodynamic resources of the world, and despoliation of the environment.