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Jim__'s Journal
Jim__'s Journal
February 12, 2012

Surprising that Rosenberg claims to be on board with all that; then claims the macro world is ...

... asymptotically deterministic.

Yet Hoefer's paper, linked to from Pigliucci's blog, explicitly claims we don't even know if the question of whether or not the universe is deterministic is decidable, yet Rosenberg is claiming that he knows it is asymtotically deterministic at the macro level. And, we are not just talking about quantum events with no large effects in the macro world, it may be impossible to determine whether chaotic system are deterministic or stochastic:


The usual idealizing assumptions are made: no friction, perfectly elastic collisions, no outside influences. The ball's trajectory is determined by its initial position and direction of motion. If we imagine a slightly different initial direction, the trajectory will at first be only slightly different. And collisions with the straight walls will not tend to increase very rapidly the difference between trajectories. But collisions with the convex object will have the effect of amplifying the differences. After several collisions with the convex body or bodies, trajectories that started out very close to one another will have become wildly different—SDIC (sensitive dependence on initial conditions - Jim).

In the example of the billiard table, we know that we are starting out with a Newtonian deterministic system—that is how the idealized example is defined. But chaotic dynamical systems come in a great variety of types: discrete and continuous, 2-dimensional, 3-dimensional and higher, particle-based and fluid-flow-based, and so on. Mathematically, we may suppose all of these systems share SDIC. But generally they will also display properties such as unpredictability, non-computability, Kolmogorov-random behavior, and so on—at least when looked at in the right way, or at the right level of detail. This leads to the following epistemic difficulty: if, in nature, we find a type of system that displays some or all of these latter properties, how can we decide which of the following two hypotheses is true?

1. The system is governed by genuinely stochastic, indeterministic laws (or by no laws at all), i.e., its apparent randomness is in fact real randomness.

2. The system is governed by underlying deterministic laws, but is chaotic.

In other words, once one appreciates the varieties of chaotic dynamical systems that exist, mathematically speaking, it starts to look difficult—maybe impossible—for us to ever decide whether apparently random behavior in nature arises from genuine stochasticity, or rather from deterministic chaos. Patrick Suppes (1993, 1996) argues, on the basis of theorems proven by Ornstein (1974 and later) that “There are processes which can equally well be analyzed as deterministic systems of classical mechanics or as indeterministic semi-Markov processes, no matter how many observations are made.” And he concludes that “Deterministic metaphysicians can comfortably hold to their view knowing they cannot be empirically refuted, but so can indeterministic ones as well.” (Suppes (1993), p. 254)


I don't see how Rosenberg can be on board with this and then claim that nature is asymtotically deterministic.

And, research indicates that animal brains have built-in chaotic subsystems - i.e we can't know whether they are deterministic or not. For instance, this excerpt from Towards a scientific concept of free will as a biological trait: spontaneous actions and decision-making in invertebrates - ( http://rspb.royalsocietypublishing.org/content/early/2010/12/14/rspb.2010.2325.full| ):


A corresponding conclusion can be drawn from two earlier studies, which independently found that the temporal structure of the variability in spontaneous turning manoeuvres both in tethered and in free-flying fruitflies could not be explained by random system noise [63,64]. Instead, a nonlinear signature was found, suggesting that fly brains operate at criticality, meaning that they are mathematically unstable, which, in turn, implies an evolved mechanism rendering brains highly susceptible to the smallest differences in initial conditions (i.e. SDIC - Jim) and amplifying them exponentially [63]. Put differently, fly brains have evolved to generate unpredictable turning manoeuvres. The default state also of flies is to behave variably. Ongoing studies are trying to localize the brain circuits giving rise to this nonlinear signature.

Results from studies in walking flies indicate that at least some component of variability in walking activity is under the control of a circuit in the so-called ellipsoid body, deep in the central brain [65]. The authors tested the temporal structure in spontaneous bouts of activity in flies walking back and forth individually in small tubes and found that the power law in their data disappeared if a subset of neurons in the ellipsoid body was experimentally silenced. Analogous experiments have recently been taken up independently by another group and the results are currently being evaluated [66]. The neurons of the ellipsoid body of the fly also exhibit spontaneous activity in live imaging experiments [67], suggesting a default-mode network also might exist in insects.

Even what is often presented to students as ‘the simplest behaviour’, the spinal stretch reflex in vertebrates, contains adaptive variability. Via the cortico-spinal tract, the motor cortex injects variability into this reflex arc, making it variable enough for operant self-learning [68–72]. Jonathan Wolpaw and colleagues can train mice, rats, monkeys and humans to produce reflex magnitudes either larger or smaller than a previously determined baseline precisely because much of the deviations from this baseline are not noise but variability deliberately injected into the reflex. Thus, while invertebrates lead the way in the biological study of behavioural variability, the principles discovered there can be found in vertebrates as well.

One of the common observations of behavioural variability in all animals seems to be that it is not entirely random, yet unpredictable. The principle thought to underlie this observation is nonlinearity. Nonlinear systems are characterized by sensitive dependence on initial conditions. This means such systems can amplify tiny disturbances such that the states of two initially almost identical nonlinear systems can diverge exponentially from each other. Because of this nonlinearity, it does not matter (and it is currently unknown) whether the ‘tiny disturbances’ are objectively random as in quantum randomness or whether they can be attributed to system, or thermal noise. What can be said is that principled, quantum randomness is always some part of the phenomenon, whether it is necessary or not, simply because quantum fluctuations do occur. Other than that it must be a non-zero contribution, there is currently insufficient data to quantify the contribution of such quantum randomness. In effect, such nonlinearity may be imagined as an amplification system in the brain that can either increase or decrease the variability in behaviour by exploiting small, random fluctuations as a source for generating large-scale variability. A general account of such amplification effects had already been formulated as early as in the 1930s [73]. Interestingly, a neuronal amplification process was recently observed directly in the barrel cortex of rodents, opening up the intriguing perspective of a physiological mechanism dedicated to generating neural (and by consequence behavioural) variability [74].

February 10, 2012

I can't get to the review that you're referencing.

I can only read the first paragraph of the review without getting a subscription to TNR which I'm not interested in. That paragraph just contains a bunch of ridiculous looking questions. So I found another review of the book, and it looks like those questions and answers are directly from the book:


It’s a seemingly simple notion, and one that many scientists and scientific-minded people would claim already to hew to, but it has surprisingly fraught implications. Rosenberg lays them out very early in Chapter 1, in a series of questions and answers. “Is there a God? No.’’ “What is the nature of reality? What physics says it is.’’ “What is the purpose of the universe? There is none.’’ Similarly, there’s no meaning to life; you and I are here because of dumb luck, and there’s no soul.


While Massimo Pigliucci hasn't yet reviewed this book, he has referred to it numerous times. For example:

Lately I hear the word “determinism” being thrown around like a trump card for all sorts of arguments, most obviously the recent discussions of free will that we have had on this blog. Moreover, as I already mentioned in passing, I am reading a new book by Alex Rosenberg that feels a lot like Dawkins on steroids (if you can imagine that), a huge portion of which is based on the assumption — which the author thinks he can derive from established and certainly unchangeable physics — of, you guessed it, determinism!

I got so sick of the smug attitudes that Rosenberg, Coyne, Harris and others derive from their acceptance of determinism — obviously without having looked much into the issue — that I delved into the topic a bit more in depth myself. As a result, I’ve become agnostic about determinism, and I highly recommend the same position to anyone seriously interested in these topics (as opposed to anyone using his bad understanding of physics and philosophy to score rhetorical points).

A good starting point from which to get a grip on the nuances and complexities of discussions concerning determinism is a very nicely written article by Carl Hoefer in the Stanford Encyclopedia of Philosophy, as well as several of the primary sources cited there, particularly John Earman's Primer on Determinism.


I've seen some good reviews of Rosenberg's book; but most of the reviews I've read have panned it.
January 15, 2012

Ronald Dworkin: Religion without God.

Dworkin gave the Einstein Lectures at the University of Bern on December 12, 13, and 14. Videos of his lectures (about 1 hour and 20 minutes each) can be found: here:

Here is an excerpt from the abstract of the lectures: :

"For most people religion means a belief in a god. But Albert Einstein said that he was both an atheist and a deeply religious man. Millions of ordinary people seem to have the same thought: they say that though they don’t believe in a god they do believe in something “bigger than us.” In these lectures I argue that these claims are not linguistic contradictions, as they are often taken to be, but fundamental insights into what a religion really is.

A religious attitude involves moral and cosmic convictions beyond simply a belief in god: that people have an innate, inescapable responsibility to make something valuable of their lives and that the natural universe is gloriously, mysteriously wonderful. Religious people accept such convictions as matters of faith rather than evidence and as personality-defining creeds that play a pervasive role in their lives.

In these lectures I argue that a belief in god is not only not essential to the religious attitude but is actually irrelevant to that attitude. The existence or non-existence of a god does not even bear on the question of people’s intrinsic ethical responsibility or their glorification of the universe. I do not argue either for or against the existence of a god, but only that a god’s existence can make no difference to the truth of religious values. If a god exists, perhaps he can send people to Heaven or Hell. But he cannot create right answers to moral questions or instill the universe with a glory it would not otherwise have.

How, then, can we defend a religious attitude if we cannot rely on a god? In the first lecture I offer a godless argument that moral and ethical values are objectively real: They do not depend on god, but neither are they just subjective or relative to cultures. They are objective and universal. In the second lecture I concentrate on Einstein’s own religion: his bewitchment by the universe. What kind of beauty might the vast universe be thought to hold – what analogy to more familiar sources of beauty is most suggestive? I propose that the beauty basic physicists really hope to find is the beauty of a powerful, profound mathematical proof. Godly religions insist that though god explains everything his own existence need not be explained because he necessarily exists. Religious atheists like Einstein have, I believe, a parallel faith: that when a unifying theory of everything is found it will be not only simple but, in the way of mathematics, inevitable. They dream of a new kind of necessity: cosmic necessity.

a little bit more ...

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