John O. Campbell
This is a excerpt from the conclusion of the new book Darwin Does Physics.
This account of the applicability of the Darwinian paradigm
to the physical sciences is dependent on a context within universal
Darwinism. Universal Darwinism may be most straightforwardly characterized as the
fact that numerous theories across a broad range of science identify a
Darwinian mechanism as responsible for the creation and evolution of their
subject matters. While the adoption of this model within any one area of
subject matter is remarkable, the fact that it has been widely documented throughout
science makes it a coincidence demanding an explanation.
Within the social sciences Darwinian evolutionary theories
are perhaps a consensus mechanism for explanations of cultural evolution. Most
of the academic fields within the social sciences have a sub-school bearing the
‘evolutionary’ prefix including evolutionary psychology, evolutionary
linguistics, evolutionary economics, evolutionary archaeology, etc..
Even in the humanities Darwinian mechanisms are rife. Indeed a near consensus view within the philosophy of science considers science itself to be a Darwinian process; one which accumulates knowledge through an evolutionary process.
A powerful and compelling Darwinian/Bayesian model explains
much of neuroscience. The Bayesian brain school views our mental models such as
sight in terms of models that are constantly being updated with sensory
information. The models which survive this Darwinian process are the ones we
‘see’.
In biology there is no scientific alternative to the
Darwinian model. Of all the subjects making up the scientific enterprise only
the physical sciences remain largely devoid of Darwinian explanation. Yet even
here a few Darwinian theories have been proposed to explain physical phenomena
at a fundamental level.
I have described some of these Darwinian theories within the
physical sciences and have suggested possible avenues by which this paradigm
may contribute to the next generation of fundamental physical theories.
Universal Darwinism is merely the observation that Darwinian
explanations are common across all fields of science. I have advocated a possible explanation for
this coincidence involving information, inference and the accumulation of knowledge.
The most influential recent idea in physics may be that
information is more fundamental than those entities such as matter and energy
which physics has traditionally understood as most fundamental. The concept of
information was first introduced to science by Claude Shannon in 1948. In a
revolutionary tour de force he defined information and proposed information
entropy as a measure of ignorance or uncertainty. Information entropy has
subsequently been shown as equivalent to thermodynamic entropy which is at the
heart of the second law and of all physics.
Significantly Shannon defined information in terms of
probability assignments. Unless an entity has assigned probabilities to the
outcomes of an event that entity cannot receive information about the
event. Further this definition of entropy involves a probability distribution
or a model of the event.
Shannon’s great discovery was quickly followed by a re-birth
of the mathematical field of Bayesian inference. Central to this field is
Bayes’ theorem which describes the precise way in which a model should be
updated when new information is received so that the model retains the greatest
accuracy possible given the available information.
From this perspective information and entropy are not simple
and may thus seem unlikely candidates to play a fundamental role in physical
theories. In essence they involve one entity modelling another; one entity
having some knowledge of an aspect of its environment and the ability to update this model as it receives new information.
I propose that this complex knowledge entity, which includes
information, probabilities, models and updating, be regarded as an inferential
system which functions to accumulate knowledge. I have also argued that
knowledge is a requirement for the existence of complexity and further that
Darwinian processes are the physical implementation of inferential systems.
Thus I attempt to explain the fact of universal Darwinism as due to nature’s
dependence on the Darwinian process to accumulate the knowledge which is
required for the existence of the complex entities studied by science.
Understanding Darwinian processes in this light moves us
beyond its common ‘reproduction with selective retention’ definition and even
the more sophisticated description by Dawkins and others in terms of
‘replicators’ and ‘vehicles’. In my view Darwinian processes invoke the
mathematics of inference within reality. Thus they involve information,
probability, models and updating. More generally they provide the mechanism by
which reality is created and evolves.
The first intuition that information is at the basis of
physics may be attributed to John Wheeler in about 1990. Since then it has proved
remarkably productive, finding confirmation in areas such as the holographic
principle, quantum information theory and the CFT/AdS duality. However within
fundamental physics the consensus view concerning information is highly
confused resulting in what E.T. Jaynes described as a standard of logic which
would be considered a ‘psychiatric disorder’ in any other field of science.
Basic to this confusion is a failure to accept the fundamental finding
that information must have a physical representation. The consensus view of
quantum theory denies this and claims that the information of quantum theory is
mathematical and has no physical representation outside of the human brain.
This misunderstanding has resulted in endless attempts to link quantum
phenomena to human consciousness.
If an actual underlying physical representation of quantum
information were discovered it would put an end to this nonsense but the scale
at which this representation exists is likely far below the scale at which
science is currently able to probe.
This was also the case with biology at the beginning of the
20th century when Mendelian ‘genetics’ was considered merely a
calculational device and not to have any physical representation outside of
human minds. Of course since then biological information has been found to have
a physical representation in the form of DNA, a physical representation many
orders of magnitude smaller than the biological phenotypes which it models.
Since the discovery of DNA knowledge within biological
science has exploded resulting in the theoretical paradigm of Neo-Darwinism.
Biology is now understood as an inferential system where knowledge that models
strategies for reproductive success is accumulated within organisms. In turn
organisms themselves are constructed according to the specifications of this
model.
Unfortunately physics may be stuck in a situation similar to
that of biology before its revolution. If, as I have argued, the role of information
within fundamental physics must be within the context of an inferential system,
physics might profitably look to better understand Darwinian processes such as biology
for analogies to guide its development. I have suggested a number of biological
analogies which may be useful in this regard.
The Darwinian/Bayesian view portrays, existence on all
levels of organization, as extremely unlikely. The single path to existence is through
knowledge and knowledge may only be gained by experience in reality. This
boot-strapping processes of evolving complexity appears to have quantum roots;
at the limits of our empirical abilities appear a few miraculous mechanisms,
the four fundamental forces, which allow one entity to experience or relate to
another. Although the ability of one entity to experience another is wondrous
it is also limited; only a scant description is ever possible.
Experience, by itself, is not sufficient to produce
complexity. Knowledge must be extracted from that experience, knowledge in the
form of strategies to avoid the harsh constraints of the second law of thermodynamics
and knowledge to out-fox competitors with evolving strategies of their own.
Bayesian inference provides the mathematical framework to
describe this process of knowledge accumulation and nature has followed those
guidelines in constructing Darwinian processes to create and evolve complex
structures throughout reality.Given the basic abilities to experience and to learn from
experience which we find at the level of fundamental physics, the complexities
of atoms, chemistry and cosmology rapidly unfold.
The evolution of life is a landmark in the cosmic evolutionary
scenario. With life and the genome of organisms a second repository of
knowledge was produced that further propelled the evolutionary search for
complex forms. On our planet at least this process appears to have accelerated
and the breakthrough of a biological knowledge repository has been rapidly
followed by the formation of neural and cultural repositories.
This view provides a homey take on our individual predicaments.
We are born into an historical context. On the basis of this initial state and our
experiences in the world we try some things. We are seven billion people trying
things which seem plausible to each of us given our experience. Our lives are
experimental, they probe the boundaries of the unknown. Each of the many
challenges we may face from feeding ourselves to being a better parent are largely
met in this kind of experimental manner.
We share our identity as experimental beings with all other complex entities; this attribute does not make us special. What makes us
special is the scope of our experiences. We are probing the bounds of our
ignorance on many fronts from experiencing the evidence of the big bang to
experiencing Shakespeare and we are accumulating knowledge at a rate, accelerating
so rapidly, that some believe we are approaching a kind of knowledge singularity .
As far as we know many aspects of our neural knowledge and
almost all aspect of our cultural knowledge are unique and are possessed only by
one species and only on planet earth. Although we are the product of natural
processes we participate within nature at a spectacular level of complexity which
may be unique. We are experiments which almost certainly, at least in exact
detail, have never been attempted in the universe before.
There is a grandeur in this view which surpasses even that
expressed by Darwin concerning the origin and evolution of species. We now have
reason to believe that the same simple mechanisms which he first discovered underlie
the creation and evolution of all complex entities found in nature and that our
species is a distinct landmark within this process of universal evolution.
Is there some relationship between Shannon's views on foundational information with its relation to matter and Einstein's spooky interaction at a distance?
ReplyDeleteWe get passed the need for a human observer by noting the environment is always measuring, collapsing wave functions etc. but why do we get entanglement? Echos, resonance, fragmented projections?
Einstein, I think was referring to, effects of quantum entanglement where causal information appears to be traveling faster than the speed of light. However it is not possible to transmit classical information using entanglement at speeds greater than light. I believes this suggests that the effects of entanglement are due to something other than the transmission of classical information. What that might be remains speculative. My own suspicion is that entangled quantum entities have a relationship and may be connected in dimensions other than space and time.
ReplyDeleteEntanglement is observed when two or more quantum entities are involved in a relationship such that none of them may be described with its own wave function, they may only be described by a wave function including the entire group.
Current research is investigating the role played by entanglement in holographic physics. Holographic physics says that a fundamental physical theories with n dimensions is equivalent to a theory in n-1 dimension which may be visualized as a boundary of the n dimensional space. The theory in n-1 dimensions is coded on this boundary and exactly describes the physics which occurs within bulk or the volume of the boundary.
Further the theory on the boundary does not include gravity but the equivalent theory of the bulk does, suggesting that gravity is emergent from quantum phenomena.
It appears the information on the boundary may be information due to entanglement in the bulk. See this paper: http://arxiv.org/abs/1405.2933
Another provocative take on entanglement was proposed by Seth Lloyd, an MIT quantum engineer. He claims that entanglement provides the classical arrow of time and the mechanism which drives the second law of thermodynamics. For instance the reason a system out of equilibrium consisting say of a cup of coffee left within a cool room, will come to equilibrium is due to the atoms of the coffee becoming entangled with the other atoms in the rooms. As the entire system approaches entanglement it approaches an equilibrium state of maximum entropy. See article: http://www.quantamagazine.org/20140416-times-arrow-traced-to-quantum-source/