07.22.10
Posted in General Relativity, biology, evolution, fitness, measurement, ontology, philosophy, science at 6:39 pm by nogre
4.2 Relativistic Evolution
4.2.1 Two Kinds of Fitness
To understand Natural Selection we need to understand fitness and how to calculate its value. One way the fitness of an organism can be understood is in terms of how well it will be able to interact with its ecology to acquire what it needs to live and reproduce. The traits of the organism will be crucial as it struggles to survive: every little adaptation or edge that the organism has can be the difference between survival and death. Therefore the traits of the organism determine its fitness.
However, the fitness of an organism is dependent upon its environment. The different situations an organism finds itself in, which are determined by the ecology and chance, will determine its ability to reproduce. For example being fast is meaningless if there is no secure footing to run on. Therefore it is the situation that determines the traits that matter and hence fitness is a function of environmental selection.
At this point it can look as if there are two distinct and incompatible methods for calculating the fitness of an organism: trait based selection and environmental selection.
4.2.2 The Equality of Trait Selection and Environmental Selection
Imagine a jaguar out in the jungle. Unbeknownst to anyone, however, his welfare is being carefully monitored by stealthy scientists. Any time the jaguar might be in trouble, be it a lack of food or an unfriendly competitor, the scientists step in and protect the jaguar from harm and do it without being seen.
An independent observer, someone who doesn’t know about the scientists watching over the jaguar, might think that the jaguar has an uncanny ability to find food and avoid dangerous situations. He might suspect that the jaguar has excellent ears that can hear danger from very far away and a nose that can smell even the faintest waft of food. He would believe that in the struggle for survival the jaguar was incredibly well adapted.
Ought we to smile at the man and say that he errs in his conclusion? I do not believe we should. We could be in the very same position as the jaguar. We like to think that we have evolved the way we have by struggling and adapting. However, we may have just as easily been assisted by some benevolent but reclusive extraterrestrials. They could be the reason our species has been able to accomplish all that we have, and we would not know.
Regardless of the existence of any such extraterrestrials, the example shows that we cannot tell the difference between struggling and surviving based upon traits, and nature conforming (or disconforming) to our adaptations. It is a matter of perspective to believe either that our adaptations were the cause of our success or if it was the environment that happened to favor us.
4.2.3 The Natural Selection Field
Instead of switching back and forth between environmental and trait selection, we can say that both kinds of selection create a field. This field is ontologically as basic as the two kinds of selection and it is what interacts with the individual organisms and environment. The interactions of an organism and the field determines the course of the organism’s life, and an ecology’s total field is determined by everything in it.
Although every organism and each ecology is unique, none are alien. By looking at similar organisms and similar ecologies, we can use natural history to determine important adaptations and key environmental features. Taken together these features specify the shape of the Natural Selection field of that ecology, which informs us on how an organism or species will interact with their environment.
An organism’s overall fitness will determine how great its effect will be in the Natural Selection field. Introducing a species with high fitness into a new ecosystem can cause great changes, whereas introducing a species into an environment that it cannot survive in will barely create a change at all. For example, when humans, with our high fitness, move into a new area, we will profoundly alter that ecology. However, if we bring a flower with us that can’t survive the cold nights in our new home, then the flower will die, barely registering any change in the Natural Selection field.
4.2.4 General Relativistic Natural Selection
With the existence of the field we can say how evolution acts upon a species. At every moment an organism interacts with a natural selection field created by its surrounding ecology. The constant interaction with the field will gradually modify the species by benefiting certain individuals and by putting others at a disadvantage.
Insofar as the natural selection field is indistinguishable from the struggle for survival, we will not be able to further analyze why species change: this theory is terminal in the same way as General Relativity. If we could show that the way organisms and species benefitted or were put at a disadvantaged by the environment, without regard to the individual adaptations of the organisms, or conversely show how an adaptation increased an organism’s fitness without regard to the environment, then an investigation into these specific phenomena could yield insight into why a species changes. However, since we cannot make this distinction, the natural selection field is the final answer as to why a species changes.
Unlike the previous theory, general relativistic natural selection is wider because it is applicable during rapid ecological changes. The prior theory of natural selection relied upon trait based analysis to determine future reproductive success and hence was unable to accurately predict success during rapid change. Relativized natural selection can say that the organisms and species experiencing a disaster (or utopia) are experiencing a change in the natural selection field. This change in the natural selection field manifests as a rapid change in the lives of the organisms. Once the ecological change is finished, then we can revert back to the old notion of natural selection.
[this is an excerpt from a longer paper, which can be found here]
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07.13.10
Posted in General Relativity, Relativity, biology, epistemology, evolution, fitness, measurement, philosophy, physics, science at 5:18 pm by nogre
New theory of evolution! Hooray!
Patched a bunch of things together to make a nice story. Fixed the little issue about fitness being circular. Expanded natural selection to apply more generally. Causal structure. Epistemological foundations. ooOoOO0Ooooooo.
And it’s good fun. I swear. Epistemology, history of physics, evolution… makes me happy. You should really read it.
Download here. [pdf, 304kb]
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03.24.10
Posted in General Relativity, Relativity, biology, evolution, philosophy, physics, science at 11:22 am by nogre
Newton famously wrote [1] [2]:
I have not as yet been able to discover the reason for these properties of gravity from phenomena, and I do not feign hypotheses… It is enough that gravity does really exist and acts according to the laws I have explained, and that it abundantly serves to account for all the motions of celestial bodies.
as a response to those who challenged him to provide causes of gravity. He said, “Hypotheses non fingo,” or, “I feign no hypothesis,” or if you will, “I haven’t even a guess.”
Earlier in a letter he wrote:
That one body may act upon another at a distance through a vacuum without the mediation of anything else, by and through which their action and force may be conveyed from one another, is to me so great an absurdity that, I believe, no man who has in philosophic matters a competent faculty of thinking could ever fall into it.
These passages show that Newton recognized a fundamental causal problem within his theory: that although his mathematics described gravitational physics, it did not provide a causal explanation. It was not until General Relativity 200 years later was this problem solved.
Recently another major fundamental theory of science has been accused of lacking the proper causal structure: Fodor & Piatelli-Palmarini’s attack on evolution, What Darwin Got Wrong. Consider what Fodor says in his recent reply to Block and Kitcher,
A mere chronicle of instances of adaptation would not therefore amount to a theory of adaptation. It would just be “natural history.” We haven’t the slightest doubt that Darwin thought that he had discovered a theory of adaptation. It was, to be sure, a pretty thin theory, as it would have to be in order to apply to evolving creatures as such, whatever their phenotypes and whatever their ecologies.
He is saying that evolution is a mere chronicle of natural history — not a cause of it — just as Newton’s gravitation described gravity without revealing its causal structure. Later he says,
[Biologists should] give up on the project of finding a mechanism for evolution and study the fixation of adaptive traits case by case. Since all the evidence suggests that they are extremely heterogeneous, this should keep evolutionary biologists busy well into the indefinite future.
This means that biologists should give up on repairing evolution and just try to explain individual phenomena moving forward, just as physics moved forward even as Newton knew his theory was on metaphysical shaky ground.
Hence it is Fodor now saying, “Hypotheses non fingo,” because he believes he can describe natural history accurately, but also has no guess as to what caused things to work out the way they did.
* * * * *
In light of this analysis, consider this statement from Block and Kitcher’s counter argument:
After our critique, Fodor and Piattelli-Palmarini have apparently decided that the crucial point is the lack of a “theory” of natural selection. But, as we have noted here, nobody needs a “theory” of the type they demand.
And this from Sober’s recent review [pdf]:
What is the net gravitational force now acting on the earth? That depends on the mass of the sun, the moon, the stars, and of everything else. It does not follow that there are no laws of gravity, only that the laws need to have numerous placeholders. FP may object to my analogy because it is always the mass of these various objects and their distance from the earth that are relevant to the gravitational force that the earth experiences. My reply is that this makes no difference…
Neither has understood the argument as presented above. If Block and Kitcher had understood, then they would have recognized that yes, for the vast majority of people, the “‘theory’ of the type they demand” is unnecessary, but it is, nevertheless, of critical importance to the likes of Newton and Einstein. If Sober had understood, then he wouldn’t have used the worst possible example to make his point: by saying it is “always the mass of these various objects and their distance from the earth that are relevant,” and not mentioning motion, we know he was only thinking about Newtonian Mechanics.
* * * * *
Should we, with Fodor, believe that we are stuck in a philosophical absurdity?
No. What I said in my original criticism of Fodor, found in What Fodor Got Wrong (18 March 09), still applies. Though the above description of the problem is likely clearer than my analysis based on his claims that Natural Selection is statistical and that the struggle for survival is only a metaphor, the problem of causal structure is the same. My solution focuses on using individual struggles as local interactions of Natural Selection — like a gravitational field in General Relativity — and hence provides the causal structure that Fodor wanted.
[EDIT 6 April 2010: I'm thinking I gave Fodor too much credit in this post. I now think his arguments amount to saying that for each instance of evolution we have, we are merely relaying natural history, not a causal explanation. The argument I attributed to Fodor above says that evolution by natural selection is natural history. Fodor must be more agnostic about evolution's ontology because of how he says it is possible to look for some alternative to natural selection in his reply to Block and Kitcher. My solution is still viable though: since I provide causal structure, this also provides how to describe evolution in a causal way.]
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03.11.10
Posted in argumentation, biology, epistemology, evolution, ontology, philosophy, physics, science at 12:42 am by nogre
1. Biology is epistemically independent of physics:
Let’s assume that biology is not epistemically independent of physics, i.e. to know any biology we must first know something about physics. However, consider evolution as determined by natural selection and the struggle for survival. We can know about the struggle for survival and natural selection without appealing to physics — just as Darwin did when he created the theory — and hence we can fundamentally understand at least some, if not most, of biology independent of physics.
2. Physics supervenes on biology:
Whatever ability we have to comprehend is an evolved skill. Therefore any physical understanding of the world, as an instance of general comprehension, supervenes on the biology of this skill.
3. Biology is just as fundamental as physics:
If the principles involved in biology and physics are epistemically independent and each can be said to supervene on the other, then neither has theoretical primordiality.
Therefore physics is not ontologically basic.
.
.
[This argument was inspired by a discussion over at It's Only a Theory start by Mohan Matthen.
And I want it to be known that I HATE SUPERVENIENCE. Basically if you use supervenience regularly then you are a BAD PERSON. The only good argument that uses supervenience is one that reduces the overall usage of the word: it is my hope that the above argument will prevent people from saying that biology supervenes on physics. For every argument in which I thought that using supervenience might prove useful, I found a much, much superior argument that did not make use of the term. I know you always live to regret statements like this, but right now I don't care.]
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01.19.10
Posted in Relativity, philosophy, physics, science at 12:22 am by nogre
[This is something I wrote before I had this blog, but I really like it and hope the readers here will find it interesting.]
The task of explaining Aristotle’s theory of place lies in the interpretation of this sentence: “Hence the place of a thing is the innermost motionless boundary of what contains it,” (Physics IV 212a20). Now the idea of a motionless boundary for perceptible and obviously movable objects seems impossibly counterintuitive. However, using Aristotle’s comments into the nature of place, we can understand how this theory extends beyond a simple boundary theory and into the modern era.
His discussion is started by making an observation:
The existence of place is held to be obvious from the fact of mutual replacement. Where water now is, there in turn, when water has gone out as from a vessel, air is present; and at another time another body occupies this same place. The place is thought to be different from all other bodies which come to be in it and replace one another. What now contains air formerly contained water, so that clearly the place or space into which and out of which they passed was something different from both. (Physics IV 208b1-8)
Aristotle then makes some tentative moves into defining what could possibly fulfill the role of place. First he discounts any idea that place could “be body; for if it were” he says, “there would be two bodies in the same place,” (209a6) and shows how this causes untold amounts of theoretical difficulty (ibid.). Then he discusses how, as that which “primarily contains each body” (209b1), place could be viewed as the form or the matter. Again he discounts either of these possibilities by noting that neither of them can be separated from a thing, whereas place may be.
The analysis turns at this point asking, “How many ways one thing is said to be in another,” (210a14) in the hopes of landing upon a useful interpretation of the notion of being-in. Aristotle entertains the idea that a thing may be in itself, or more specifically, in itself “qua itself or qua something else” (210a27). He gives the example of a jar of wine being in itself in virtue of the whole’s description in terms of its parts: the jar of wine is not reducible to a jar or some wine, but to their specific combination. Hence that which is a subject may potentially be a container as well, as the jar is the container of the subject ‘jar of wine’. However, he says this is impossible as no object is actually like this: the wine would have to be an equal part container, and the jar an equal part wine, else the whole of the ‘jar of wine’ will not be completely in itself. It is in virtue of being different that the jar and the wine may come together, and hence he concludes that, “since the vessel is no part of what is in it (what contains something primarily is different from what is contained), place could not be either the matter or the form of the thing contained,” (210b27).
Aristotle then considers two sorts of boundary theories. First, place is such that it is “some sort of extension between the extremities,” (211b7). However, this sort of boundary exists independently of what is bounded and is permanent. Insofar as anything moves, the place will change, and there will be two problems generated: 1. The boundary between, for example, the wine and air moving in a jar will be exactly coincident with the boundary between the air and wine, and each of these two boundary extensions will be partially coincident but must also be unique, and 2. There will be a place at the boundary of the displaced place, and so an infinite regress of places associated with previous places will be generated.
Finally Aristotle says, “place necessarily is… the boundary of the containing body at which it is in contact with the contained body,” (212a6). Then, interestingly, he says, “Place… is rather what is motionless,” (212a17) and then, “Hence the place of a thing is the innermost motionless boundary of what contains it,” (212a20). So how are we to make sense of containers that give us the boundaries but also do not move?
If we take our interpretation directly from the previous discussion of boundary, Aristotle seems to have made an awfully strange claim: place is a like a container that something perfectly fits in, and yet that container cannot itself move although what is contained therein necessarily can. However, I would like to suggest taking him at his word in regards to place being necessarily a boundary. It is necessarily a boundary of the containing body which is in contact with the contained body, but it is not sufficient that it be the boundary that most have in mind. What has been missed by regarding the boundary as necessary and sufficient is the incorporation of Aristotle’s primary intuition into how we know place exists.
For us to notice any motion we need something stationary relative to the thing moving such that we may observe the motion as motion. A stationary backdrop is necessary to view change. Consider this example: it is a common experience to be sitting in traffic next to a bus. When the bus starts to slowly pull forward sometimes it is possible to get the sensation that you have started to move backwards. This sensation lasts until some other fact informs you that it was not you who were retreating, but the bus advancing. In the first instance, the place that you inhabited was defined in terms of a stationary bus: any motion that occurred was relative to that fixed point. When you realized it was the bus, and not you, that was moving, whatever it was that informed you that you were stationary became incorporated into the place. Perhaps you saw a building and since it was not moving your senses of place and motion were reevaluated to accommodate this new information. Hence two different places were involved in this scenario: one corresponds to your (belief of) moving backwards and the other to the forward motion of the bus. The first place has the innermost motionless boundary [illegitimately] defined in terms of the bus [since the bus was in motion], and the second has an expanded sense of place to include something motionless relative to both you and the bus. Place, therefore, not only encapsulates that which is moving, but also whatever is observing the motion and an independently stationary object.
When Aristotle says, “First then we must understand that place would not have been inquired into, if there had not been motion with respect to place,” (211a12) he was not making an idle comment on the ‘discovery’ of the phenomenon of place. Instead, he was beginning his analysis with the most important feature to be explained. Galilean relativity holds fundamentally that motion can only be defined relative to some “system of coordinates” (Einstein p. 14), i.e. something motionless with respect to the moving object. Although Aristotle did not have the benefit of Descartes’ mathematical works he still recognized the need for a reference system unique to each motion.
Now that the meaning of the ‘motionless’ criterion has been explained, what does ‘innermost’ mean if the boundary may include objects at a significant distance from the one we are describing? The Earth is, in some sense, the place of all sublunary objects, but it is surely not the innermost boundary. Again appealing to the exact phenomenon that Aristotle was dealing with yields the correct explanation: the motion of an object with respect to its place cannot be described by saying that the place of the thing is Earth. Instead the innermost boundary should be the first boundary for which the description of motion and place of the thing make sense. In the example of swirling wine in a jar (with the jar held steady but the wine still moving), the place of the wine can be said to be the jar because it describes the closest motionless boundary. One might say that the place of the wine is equally on the table, or in someone’s hand, but both of these descriptions are related to motion other than that of wine swirling in the jar, and are really just shorthand for ‘the jar of wine is on the table, or in hand’ (consider, “The wine is on the floor,”: no swirling to be had). The correct place of the moving bus example was the street, which could reasonably include things such as houses and other stationary objects, the most important one being the road. Aristotle gives the ancient version of this, just before his final definition of place, in terms of the motion of a boat, such that it must be defined in terms of the whole river, which is taken as stationary (212a19).
One may think that I am being too charitable to Aristotle at this point because it may look that I have implied that the ‘innermost’ criterion of the theory will do all the work of translation between coordinate systems, which it does not seem to do. However, Aristotle allows for the fact that we may treat a vessel such as a boat as a “transportable place” (212a14). Hence we may allow for the things within a boat to have motion independent of a preferred fixed reference system. This connection drawn between vessel and place gives the final aspect needed for a true relativity theory. Historically the example of a boat on a river (212a19) is striking because Galileo uses the same example of a ship in his Dialogue Concerning the Two Chief World Systems (Salgado).
Commentary
Historically Aristotle’s theory of place has been treated as a simple boundary theory coupled with a few very strange statements that were assumed to be preliminary investigations into different methods of solving blatant paradoxes (King 91). My suspicion for why this happened is twofold. First, philosophy of place sounds like the most dry and uninteresting subject possible and hence it was not given its due study time over the course of history (after Aristotle that is). Secondly, the modern formulation of relativity is given according to Einstein’s theory of Special Relativity. Insofar as this is a theory of relative motion, it is easy to overlook the fact that it applies to objects without motion, things in place. Aristotle’s formulation is none the weaker because of the way he cast his theory, but it is much more obscure to the modern reader, as Aristotle’s relativity is developed in a somewhat inverse way with respect to modern relativity.
Bibliography
- Barnes, J. ed. The Complete Works of Aristotle v.2, Princeton U. Press, Princeton 1995
- Einstein, Albert Relativity: The Special and General Theory Lawson trans. Pi press, NY, NY 2005
- King, H. R., “Aristotle’s Theory of TOPOS,” Classical Quarterly #44 1950, pp. 76-96
- Salgado, Rob “Galileo’s Parable of the Ship” http://physics.syr.edu/courses/modules/LIGHTCONE/galileo.html Accessed 2/24/06
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12.31.09
Posted in Relativity, biology, evolution, measurement, philosophy, physics, science at 4:48 pm by nogre
I have previously argued that the history of species must be treated like a evolutionary trajectory: we can only appreciate a species in a relative sense, just as we must evaluate physical trajectories relative to our own motion.
But what happens when we try to measure the very small in physics? We find there is a limit to the precision at which we can measure, as given by the uncertainty principle.
This suggests that there may be some similar limit when it comes to measuring small changes in species. The more we try to pin down exactly what a species is, the less sure we will be about its future and the more we measure the direction the species is heading, the less sure we will be about exactly what constitutes that species.
If genetic drift is just another way of saying that we cannot pin down the exact genetic make-up of a species then drift may be considered to be an instance of the uncertainty principle.
and HAPPY NEW YEAR
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09.29.09
Posted in biology, ontology, philosophy, physics, science at 12:54 am by nogre
I saw that Richard Brown is working to defend physicalism against a priori arguments. He says that most (all?) arguments use the same intuitions found in the zombie-knowledge arguments.
This got me to thinking about a priori arguments against physicalism and I came up with something different:
If physicalism is, as Dr. Brown says, “… the view that only physical things exist. Physical things are those things that are postulated by a completed physics,” then I wonder who made physics king? I’d have to assume that there is something within science that specifies physics as most fundamental.
However, science itself, or more specifically philosophy of science, is discipline agnostic. There is nothing within the basic structure of science to specify physics as the foundation. Maybe it is biology that is fundamental, maybe it is psychology, maybe something else; the point is that there is no a priori reason to prefer one over any of the others. If there is nothing that distinguishes physics as a ground for the other sciences, then there is no reason that physicalism should be taken as a fundamental philosophy.
At this point the physicalist would want to find some grounds for the claim that physics is fundamental. This is problematic though: nothing could be used from within physics because that would be question begging. On the other hand, if we try to justify physics as fundamental by appealing to something outside physics, then isn’t that thing that provides the justification more fundamental than physics itself? If we have to justify the claim ‘physics is fundamental’ by appealing to something even more fundamental, then physics is no longer fundamental because it needs an outside justification. Therefore any justification for physicalism is inherently question begging or self-contradictory.
I know I haven’t disproved physicalism; at best I’ve indicated that justifications for it are bad. And if any justification is bad, then the position is indefensible. Since most philosophers don’t like to hold indefensible positions, perhaps this is sufficient.
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08.14.09
Posted in philosophy, physics, science at 7:09 pm by nogre
Today, as Google/Wikipedia tells me, is Hans Christian Ørsted’s birthday. He coined the term ‘Thought Experiment’ and, if he had done nothing else, I’d still think he ought to be remembered far and wide.
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05.22.09
Posted in biology, epistemology, evolution, independence friendly logic, ontology, philosophy, physics, science at 9:23 pm by nogre
Q: What is a multiple star system?
A: More than one star in a non-reducible mutual relationship spinning around each other.
Q: How did it begin?
A: Well, I guess, the stars were out in space and at some point they became close in proximity. Then their gravitations caused each other to alter their course and become intertwined.
Q: How did the gravitations cause the courses of the stars to become intertwined? Gravity does one thing: it changes the shape of space-time; it does not intertwine things.
A: That seems right. It is not only the gravities that cause this to happen. It is both the trajectory and mass (gravity) of the stars in relation to each other that caused them to form a multiple star system.
Q: Saying that it is both the trajectories and the masses in relation to each other is not an answer. That is what is in need of being explained.
A: You are asking the impossible. I have already said that the relation is non-reducible. I am not going to go back upon my word in order to reduce the relation into some other relation to explain it to you. The best that can be done is to describe it as best we can.
Here is the problem: If you have a non-reducible relation (e.g., a 3-body problem or a logical mutual interdependence) then you cannot explain how it came to exist. Explaining such things would mean that the relation was reducible. But being unable to explain some scientific phenomenon violates the principle of science: we should be able to explain physical phenomenon. Then the relation must not be non-reducible or it must have been a preexisting condition going all the way back to the origin of the universe. Either you have a contradiction or it is unexplainable by definition.
–
What can we do? You can hold out for a solution to the 3-body-problem or, alternatively, you can change what counts as explanation. The latter option is the way to go, though, I am not going into this now.
For now I just want to illustrate that this problem of non-reducibility and explanation is pervasive:
Q: What is a biological symbiotic relationship?
A: More than one organism living in a non-reducible relationship together.
Q: How did it begin?
A: Well, I guess, the organisms were out in nature and at some point they became close in proximity. Then their features caused each other to alter their evolution and become intertwined.
Q: How did the features cause the courses of their evolution to become intertwined? Physical features do one thing: they enable an organism to reproduce; they do not intertwine things.
A: That seems right. It is not only the features that cause this to happen. It is both the ecosystem and the features of the organisms in relation to each other that caused them to form a symbiosis.
Q: Saying that it is both the place the organisms are living in and their features in relation to each other is not an answer. That is what is in need of being explained.
A: You are asking the impossible. I have already said that the relation is non-reducible. I am not going to go back upon my word in order to reduce the relation into some other relation to explain it to you. The best that can be done is to describe it as best we can.
As you can see, I am drawing a parallel between a multiple body problem and multiple organisms that live together. Like the star example above, there is no way to explain the origins of organisms living together. Even in the most basic case it is impossible.
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