Wikipedia:Reference desk/Archives/Science/2012 August 28

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August 28

Symmetries of the Universe

The book, Concepts of modern mathematics by Ian Stewart in its chapter on symmetry, states that:

In mathematical physics, laws like the conservation of energy follow from certain (postulated) symmetries of the universe.

My questions are,

1)What are those postulated symmetries?

2)How does the law of conservation of energy follow from them intutively speaking?

Thanks--Shahab (talk) 05:34, 28 August 2012 (UTC)

See Noether's theorem, which should explain all about the relationship between conservation laws and symmetry. --Jayron32 05:40, 28 August 2012 (UTC)

Was the flies in Autstalia tamed so that they mainly feed on plants but not trash?

I have heard in a Chinese article that the Australians put a fly on the $50 bank note, and the reason is that they tamed by cleaning every dirty place and forced the flies to change their diets into plant nectars and no longer becoming a health hazard. Is that ever possible? There can be animal feces everywhere in the wild and I think just cleaning trashes in cities will not affect the flies’ diet much.--211.162.75.202 (talk) 06:05, 28 August 2012 (UTC)

I am looking at an Australian fifty-dollar note. Wikipedia's article about it says nothing about flies. I can't see a fly anywhere on it, so it sounds like the Chinese article has got it wrong. I have never heard anything about every dirty place in Australia being cleaned to the extent that flies changed their dietary habits. Dolphin (t) 06:34, 28 August 2012 (UTC)

I suspected that this weird post was from a troll, but as he gelocates to Guandong China, and the linked articles is a Chinese site, here is a definitive answer:-

1. I am an Australian, located in Australia;

2. I have an Australian $50 note in front of me right now;

3. There are no flies on this note. It only has pictures of famous Australians, a Goverment building, and drawings of what appear to be sheep shearing equipment.

4. Flies were once quite a problem in the Australian city in which I live, but the authorities about 18 or 20 years ago changed everybody over from using galvanised iron rubbish bins to specially designed rigid plastic rubbish bins (known as "wheelie bins"), as well as using better landfill practices. These plastic bins have lids that make a good seal on the bin, so the flies can't get at the rubbish. This produced a marked drop in the fly population, making it possible to eat outside for the first time. Since then, the flies have evolved into a more resourcefull and hardy sort, and numbers have increased a little, but they remain not a problem. It is also normal practice to seal food rubbish in palstic bags before placing in the bin, making it very difficult for flies, and eliminating any smell.

Incidentally, most local goverments have passed ordinances making it an offence to leave faeces (e.g., from pet dogs) in place on the ground, but this is to make footpaths and parks pleasant for walkers and joggers, not to control the fly population. Wickwack124.178.52.176 (talk) 06:43, 28 August 2012 (UTC)

I guess the 2 dollar coin has the Southern Cross which could look like flies to the easily confused. Sean.hoyland - talk 06:52, 28 August 2012 (UTC)

The fifty-dollar note also has the Southern Cross - in the transparent window. These five stars might look like splattered flies, but they don't look much like live ones. Dolphin (t) 07:10, 28 August 2012 (UTC)

They don't look anything like splatted ones either - they are way too precisely drawn uniform and delimitted 7-pointed stars, with one 5-pointed one. Wickwack124.178.52.176 (talk) 10:15, 28 August 2012 (UTC)

There's been a reduction in the fly population in Australia over the past 30 years or so due to the introduction of carefully chosen dung beetles. HiLo48 (talk) 07:21, 28 August 2012 (UTC)

But I should also assure the OP that we haven't eliminated the fly problem. In parts of the country, at certain times of the year, little bush flies can still be very common, and March flies, which seem to have trouble reading the calendar and appear in far more months than March, can still be bloody pests! HiLo48 (talk) 09:13, 28 August 2012 (UTC)

Dung beetles are only relavent in farming areas. Most Australians live in cities - where cattle dung is not available. Wickwack124.178.52.176 (talk) 10:12, 28 August 2012 (UTC)

As I understand it (and I don't claim to be an expert) the reduction of flies on country areas is reflected in city areas too. Flies travel on the wind. We couldn't have had all our modern outdoor eating areas 40 years ago. HiLo48 (talk) 10:23, 28 August 2012 (UTC)

We couldn't have them 20 years ago. It was the wheelie bins that fixed it, and was the justification for the cost. Flies might travel on the winds, but in Perth, we are right in the trade wind zone, and on the coast. Those poor flies 20 years ago must have come from Africa 6000 km away then. Wickwack124.178.52.176 (talk) 14:52, 28 August 2012 (UTC)

Fair comment. I'm in Melbourne where the hot summer winds come from the north, and that's where all the flies are. HiLo48 (talk) 20:40, 28 August 2012 (UTC)

Thanks for the information above. Is it true that fly never ever appeared on any Australian notes--the ones being used now and the previous ones?--211.162.75.202 (talk) 07:28, 29 August 2012 (UTC)

Yes, it is true. Dolphin (t) 07:36, 29 August 2012 (UTC)

The CSIRO released sterile blowflies in the 70s to reduce the fly population[1] is that what you are thinking of? Images of Autralian banknotes are available at this article--Surturz (talk) 05:07, 30 August 2012 (UTC)

OK, the old $50 note has a picture of Ian Clunies Ross, who among other things developed an immunization for dogs to protect against the dog-tick. Drawing a long bow, but maybe that factoid got mangled in translation? --Surturz (talk) 05:15, 30 August 2012 (UTC)

The resolution of reality

Hi a number of thoughts have just swept through me and I have to ask this multi-pronged question. Assuming what we see is made up of zillions of pixels, what is the resolution of reality (let's say per cubic metre)? When do you think audiovisual equipment will be able to catch up with the processing power and resolution needed to create an (holographic?) image identical to our eye's optical mechanism? Then, finally, do we dream in the same resolution as what we see? If so, does this imply that our brain has enough computing power to interpret stored images in the same way it interprets reality passed on from the retina? Sandman30s (talk) 15:06, 28 August 2012 (UTC)

Some basic starting comments; you only see very good resolution on a small area of focus at any moment. Your brain interprets a whole load of things in different places (so you are much more sensitive to movement and change than to other details); "processing" is therefore highly selective. Also dreams are mainly symbolic, rather than pixelated. --BozMo talk 15:11, 28 August 2012 (UTC)

The basic reception equipment in each eye is about 120 million rods (brightness and darkness) and 7 million cones (color). These don't really map onto "pixels" — the eye doesn't work the way you are describing it, it's not a simple photoreceptor circuit — but it gives you some idea about the richness of human visual perception. Fooling eyes is in some ways a lot easier than that — distance matters a lot, as does lighting. We can already do plenty of things that would fool the human eye at a distance. What is trickier is when someone is looking at something very close up. --Mr.98 (talk) 17:07, 28 August 2012 (UTC)

It isn't the eye you have to fool, it's the brain. The visual system also doesn't work like a camera, not so much because there aren't pixels, but because there's nothing at all like film. The modern digital camera is a better analogy for the human visual system because, just like you need a computer program to translate the data file that contains the image before it looks like an image, you need the brain to interpret the data from the eyes in order to understand what the eyes are seeing. Just as playing around with the code on said computer file will drastically change the picture captured by the camera, the visual perception system is easily fooled. See Visual perception. It is quite easy to devise optical illusions which don't fool the eye at all. The eye records the same visual data, but the data is carefully constructed as to fool the brain. The brain does all sorts of processing to make sense of our three-dimensional world, and not all of it is so straight forward. Gestalt psychology is one perspective that deals some with how the brain visually processes incoming data. It isn't a universally accepted explanation, but it is insightful in places. --Jayron32 17:41, 28 August 2012 (UTC)

What our brains perceive through our senses is a very tiny part of what information is actually out there in the electromagnetic spectrum. And that's not including dark matter and energy. So the "resolution of reality" concept is flawed: if we answered that question according to the capacity of the human brain, it wouldn't be a representation of reality itself, merely a representation of the human perception of reality - and there's a vast difference. --TammyMoet (talk) 18:08, 28 August 2012 (UTC)

Would entities exist without minds to distinguish them?

The free will discussion above is about to be archived, but there is still a pending question, so I have continued it here.

prior free will discussion for context
The following discussion has been closed. Please do not modify it.
A machine with free will (arbitrary break 1) We are all mathematical algorithms, there is no such thing as a physical universe, all that exists is math. Qualia are computational states of algorithms. Count Iblis (talk) 22:38, 24 August 2012 (UTC) We are not mathematical algorithms at all, there is no such thing as math: all that exists is the physical universe.... AndyTheGrump (talk) 22:44, 24 August 2012 (UTC) The truth, as usual, lies somewhere between those 2 extreme positions. -- ♬ Jack of Oz ♬ [your turn] 22:49, 24 August 2012 (UTC) No. The truth is that all that exists is the physical universe by definition. To say otherwise is farcical. 203.27.72.5 (talk) 23:21, 24 August 2012 (UTC) Not to spoil the fun by throwing in a reference (which suggests this should really be running on the humanities desk, or maybe misc, since we're well into philosophy and logic), but try some Wittgenstein: 1 The world is all that is the case. 1.1 The world is the totality of facts, not of things. 1.11 The world is determined by the facts, and by their being all the facts. 1.12 For the totality of facts determines what is the case, and also whatever is not the case. 1.13 The facts in logical space are the world. 1.2 The world divides into facts. 1.21 Each item can be the case or not the case while everything else remains the same. Tractatus Logico-Philosophicus. 86.169.212.200 (talk) 21:05, 25 August 2012 (UTC) Correct me if I'm wrong, but haven't later philosophers rejected this position - including Wittgenstein himself? AndyTheGrump (talk) 04:15, 26 August 2012 (UTC) It is still true that math exists. To say otherwise would cause great distress to the workers at the Mathematics Reference Desk. And it is still true that not everything is math. And it is true that not everything is encapsulated in "the physical universe". For example: ideas, thoughts, feelings, mathematical concepts ... -- ♬ Jack of Oz ♬ [your turn] 05:09, 25 August 2012 (UTC) What is an thought besides a collection of electrical signals firing along synapses in your brain? Is that not physical? --Jayron32 05:15, 25 August 2012 (UTC) Let me just point out that 203.27's supposed "definition" of the universe pre-supposes that everything in the universe is physical. That is just about the most unscientific and prejudiced and close-minded position one could possibly take. It's also not a universe that I have any knowledge or experience or understanding of. -- ♬ Jack of Oz ♬ [your turn] 10:11, 25 August 2012 (UTC) I'll note by my personal crazy model above, everything actually isn't math - math is deterministic, and the point of the causality violation is to create an opening for something outside the known universe, beyond our ability to examine and perhaps to comprehend, to potentially affect it. The free-willed decisions actually all become boundary conditions of the universe. Wnt (talk) 12:50, 25 August 2012 (UTC) It is a World 2 object in Popper's three worlds ... besides being a collection of electrical signals firing along synapses in your brain. To put it that way is true, but reductionist - other collections of electrical signals firing in your brain might not be thoughts, but smells, or migraines, or fits, so a higher-level description is commonly more meaningful. (Wait, all those things are probably world 2 objects as well. Damn. Still, a thought is a thing in its own right, an emergent thing.)  Card Zero  (talk) 15:40, 25 August 2012 (UTC) You are correct- things like mathematical and sciontific concepts are not part of the physical universe by any menes.Aliafroz1901 (talk) 10:45, 25 August 2012 (UTC) Or maybe they are, the jury is still out, but the effort put into discussions like this are probably better put into articles like physicalism. Sean.hoyland - talk 11:20, 25 August 2012 (UTC) Yeah, but then we'd need sources. Philosophy is like feces or potential employees - everyone has excess to give away, but who wants to consume it? Wnt (talk) 12:46, 25 August 2012 (UTC) Like I said above, everything is math. When we assume that what we experience is a physical world that is somehow more than a purely mathematical entity, we actually don't know what that fundamentally is. So, assuming that a physical world that is different from pure math exists is religion, it isn't science. Most scientist do believe in a physical world, but then more than a century ago, most scientists were deeply religious people. If you feel pain, then this is not fundamentally caused by electrical signals, it is caused by the computation your brain performs. A huge analogue computer that would run the same algorithm as your brain is running and processing the same data would experience the same pain, even though it consists of gears. Count Iblis (talk) 19:10, 25 August 2012 (UTC) So, if nothing physical exists then what's running the algorithms? 203.27.72.5 (talk) 20:20, 25 August 2012 (UTC) The algorithms are not really run, they only exist in a mathematical sense. All possible algorithms thus exist. One of these algorithms is the formal description of your brain at this moment when you read this part of the sentence, one slightly different algorithm is the formal description of your brain at this slightly later moment when you read this. Count Iblis (talk) 04:07, 26 August 2012 (UTC) To answer the original question, it is easy to create a machine with free will as it is conventionally defined. The creation process is called Procreation. --BozMo talk 21:34, 25 August 2012 (UTC) Our brains can take in information and we can use that information — plus our existing world views, emotional states, and what have you — to make deliberative decisions about our actions. We can weigh possible outcomes, things we desire or desire to avoid, and come to conclusions. We can even come to very unintuitive or unexpected conclusions. We can use information, values, and empathy to decide what sorts of activities we agree we feel comfortable undertaking, and those which we would desire to never undertake. To me, this is as much as anyone seems to ever really mean by "free will" — I don't actually see debates about causality and materialism to be germane to the topic. Even setting aside the question of what consciousness really is — we have no clue, and it is a mighty significant thing to know nothing about when talking about such things — to me all anyone really wants to know is, "Are we responsible for our actions? Do we actually make decisions?" We feel that we are. We act like we are. Very few people who are not looking to excuse their prior actions ever seem to really ascribe to the philosophy that they are completely out of control of their own actions. That strikes me as pretty "good enough." I am not quite willing to say that my consciousness is totally illusory — it feels pretty "real" to me, and though that is just one datapoint, over time I've come to believe (when I ignore all of the postmodernism and language-games talk that was drilled into me by professors and try to evaluate it in a completely honest, personal way) that it's actually a pretty significant datapoint. But moving to the meat of the original question: I see no a priori reason to think that we could not imbue a machine with the same faculties as a human brain. This would include whatever appears to be a component of "free will", as defined above. How to do this, I have no idea, and I doubt anyone else alive does either. The human brain is still virtually terra incognita when it comes to understanding the physical basis of consciousness. I suspect we're still a long way off from making sense of it. We probably need to make sense of what makes us us before we can make other things us. --Mr.98 (talk) 01:54, 26 August 2012 (UTC) Bodies (hylomorphic substances) and those things that exist in relation to bodies (aristotelian categories) exist. Mathematics doesn't exist by itself. If it did, would it be in base two? Or base ten? Or base e? The assertion is absurd. Mathematics is a perspective on reality that observes quantity but ignores quality. Consciousness is not a thing, or a body. Consciousness is a relationship, a sort of harmony that exists between certain types of bodies, in respect to their forms, and mathematics is a complex sort of such relationship. To insist that mathematics as such existed back when there were only fish or only molten planetoids or dense clouds of plasma makes as much sense as insisting that documentary films did. μηδείς (talk) 02:18, 26 August 2012 (UTC) Medeis - I am not sure I completely follow what you mean by "mathematics doesn't exist by itself". Your analogy with documentary films (which I think we can agree have a form of existence) seems to imply that mathematics exists in some sense of "exists", just not "by itself". Is that correct ? If so, can you clarify what "by itself" means by giving an example of something that does "exist by itself" ? Gandalf61 (talk) 09:00, 26 August 2012 (UTC) Fundamentally, existence just is what it is. We use various concepts to manipulate it mentally, allowing us to act effectively in it. We view reality fundamentally as consisting of entities, "things", which exist in themselves. We can say, there is a tree, there is a person, there is a rock. Entities have attributes (qualities) and exist in certain relationships. A ball can be red, can be round, can have all sorts of attributes. But we don't talk of there being a red, or there being a round, walking down the street, apart from a red or round thing. Attributes exist, but they don't exist in themselves, but rather of entities. Likewise relationships. To be aware of, to be as big as, to be the father of, these relationships exist between entities (and in more complex ways, like analogies, which are relationships between relationships, and so on.) Again, we do not (unless we lose focus) talk about an "aware of" (i.e., a consciousness) or an "as big as" walking down the street independent of any entity. Don't get me wrong, redness doesn't exist any less than ballness or nearness. They all exist. An entity is the sum of its attributes and its relationships through time. It is also the sum of its substance (or "parts") and of its form (or "shape"). All of these things are real. Sweetness is real--it just doesn't exist on its own, or separate from a sweet thing and a creature capable of tasting it. Sweetness is a relational attribute, not a thing, not a part of a thing, not an atom. See Aristotelian category for some of the various ways in which we say things exist. Mathematics is a complex set of ideas (which are relations, not entities) about quantitative relationships. Mathematics is quite real, but it is an abstraction that exists as a relation between conscious entities and their environments. And the form in which we express those relations is to some extent arbitrary. We can cut an apple in two equal pieces (the same as 10 equal pieces in base two) and talk about 1/2 of it or 50% of it. The thing itself is what it is, the mathematical description of it is just as real, but real as a relation between us as conscious measurers and the entities in question. Humans are quite adept at abstraction. We can ignore our senses for the moment and picture everything in terms of its mathematical description (pythagorean idealism) or in terms of atoms and void (naive/reductive materialism) or in terms of minds and Ideas (Platonism). And we might in flights of fancy even be tempted to say that only numbers or particles are real. But without our direct awareness of entities and attributes (the ability to read the red hand on the meter of the geiger counter) we would have no contact with them. Numbers and particles and the like cannot claim to be real if the perceptions they are abstracted from are not. μηδείς (talk) 19:20, 26 August 2012 (UTC) Suggested reading in order of difficulty: Ten Philosophical Mistakes by Mortimer Adler, Introduction to Objectivist Epistemology, 2nd Ed. by Ayn Rand, An Introduction to Logic by H. W. B. Joseph μηδείς (talk) 19:46, 26 August 2012 (UTC) Okay, so when you say "We view reality fundamentally as consisting of entities ...", does this mean that the distinction you are making between entities, attributes and relationships is a function of how we (i.e. human beings) perceive reality, not something that is inherent in reality itself ? So categorising a tree as an entity is a subjective judgement, not an objective fact ? That makes sense to me because singling out the tree rather than its branches, leaves or cells, or the forest of which it is a part, or the acorn from which it grew, or the planks which it will become is clearly a somewhat arbitrary slicing of reality. Gandalf61 (talk) 11:57, 27 August 2012 (UTC) Very pertinent question. Remember that consciousness is a relationship between a certain type of being and its environment. If we were beings of a vastly different scale, galactic or atomic in size, we would obviously have different ways of perceiving reality. If one takes the consensus view of quantum mechanics, it is unlikely we would perceive atoms the way we as humans perceive billiard balls. (I don't want to endorse any theory a priori here, philosophy doesn't entitle us to speculate on facts that only science can discover.) If we were "atomies" we would not perceive trees directly, or likely even color, given the scale difference. But our scientists might discover these things in the way that ours have discovered radio waves and that the Milky Way is a spiral galaxy. Whether or not "atomies" would apprehend things in terms of entities and events is a matter of speculation. But the fact that we perceive things that way is not subjective, so much as relative, and relative in an objective way. Humans have an objective nature--their brains and sense organs have a definite nature; they work in a definite way. Reality has a definite nature--it is what it is. Our consciousness of reality is veridical if it conforms to the nature of our sense organs and of reality. We can open our eyes and carefully observe things, or stick our fingers in our ears and hum, or have our tea-leaves read instead of our MRI. The fingers-in-the-ears or the tea-leaves strategies are the subjective ones. They are the ones where the subject creates the contents of its consciousness without relation to the facts of reality. The people who open their eyes and see reality are the ones getting objective knowledge--even if one man is colorblind, and the other not, the statement "this is the way these things look to me in these circumstances" is objectively true for both. The mistake would be to insist that the concepts of entity and attribute and relation are intrinsic to reality. It would be just as presumptuous to say those concepts exist in reality as its ultimate fundamental makeup without relation to our consciousness of reality as it would be mistaken to say those concepts exist only in our minds without relationship to reality. For most of the history of philosophy people have insisted on an a priori metaphysics. "Ultimate" reality is: earth, air, water and fire; atoms and void; number and harmony; spirit and clay. That is substituting metaphysics for science. And it means every scientific discovery threatens to overthrow your philosophy. Things are what they are. Our concepts are useful if they conform to our means of comprehending reality. Concepts like substance and form; entity, attribute relation (and event, and so forth) are invaluable. Most philosophical mistakes result from their misapplication. Consciousness is not an entity. Evil is not a substance: "It contains pure evil!") Ideas are not things. But neither are these things unreal. On the nature of concepts and objectivity as relational, read Introduction to Objectivist Epistemology. On the ubiquity and danger of category mistakes read Ten Philosophical Mistakes]. μηδείς (talk) 16:52, 27 August 2012 (UTC) Okay, so without the relationship that we call conciousness (and, specifically, human conciousness or something very similar to it) there can be no entities that we call trees or rocks, in the same way as there can be no mathematics without conciousness. Gandalf61 (talk) 09:13, 28 August 2012 (UTC) The notion that the reality of the universe could exist purely as mathematics is, well, disturbing for a number of reasons, not the least of which is, that for every irrational number A.BCDEFGHI..., there are truncated versions A.0, A.B, A.BC, A.BCD, etc. So for every instant in the cosmos when you're sitting there reading this message the way you think you should be, there are an infinite number of instants where you're sitting there missing your feet, legs, waist ... and an even "larger" infinite number where they're replaced with some other thing, cat bodies, refrigerators, Cthulhean monsters. But I think that because the existence of a single perfect, "properly formed" moment in space and time is so infinitely unlikely amid the mass of numbers, and we perceive (I hope) such an instant presently, it is therefore equally improbable that this model of the formation of reality is truth. Wnt (talk) 10:28, 26 August 2012 (UTC) That's (sort of) an analogue if the Boltzmann brain problem for the mathematical universe. But then all known physical theories of the universe suffer from the same disease. However, I have found a solution to this problem for the case of the mathematical multiverse, which is natural, not some ad hoc fix, which doesn't have an analogue for "physical theories". Count Iblis (talk) 15:20, 26 August 2012 (UTC) I'm not familiar with Boltzmann brain, but the "paradox" they describe in that article is easily solved; I've ranted on about it here half a dozen times before. We are always in a state of relatively low entropy because we always keep moving the goalposts. The universe apparently gets larger and cooler in very rough proportion to its age, and the time its residents are willing to wait for "interesting events" expands in like proportion. From the subjective point of view, the most important laws of physics are always changing. Someday protons will be exotic particles found only in cutting edge laboratories, but the people studying them will be made out of "neutrino nuggets" or something, tiny insubstantial particles that take billions of years for one tick of the clock to pass. But I digress, and admittedly, on a favorite crank idea. Wnt (talk) 03:50, 27 August 2012 (UTC) http://arxiv.org/abs/1202.4545 "The Relativity of Existence Stuart Heinrich (Submitted on 21 Feb 2012 (v1), last revised 23 Aug 2012 (this version, v2)) Despite the success of modern physics in formulating mathematical theories that can predict the outcome of experiments, we have made remarkably little progress towards answering the most fundamental question of: why is there a universe at all, as opposed to nothingness? In this paper, it is shown that this seemingly mind-boggling question has a simple logical answer if we accept that existence in the universe is nothing more than mathematical existence relative to the axioms of our universe. This premise is not baseless; it is shown here that there are indeed several independent strong logical arguments for why we should believe that mathematical existence is the only kind of existence. Moreover, it is shown that, under this premise, the answers to many other puzzling questions about our universe come almost immediately. Among these questions are: why is the universe apparently fine-tuned to be able to support life? Why are the laws of physics so elegant? Why do we have three dimensions of space and one of time, with approximate locality and causality at macroscopic scales? How can the universe be non-local and non-causal at the quantum scale? How can the laws of quantum mechanics rely on true randomness?" Count Iblis (talk) 23:33, 26 August 2012 (UTC) You don't need to write a paper to explain why existence exists. It takes just six words: There was nothing to prevent it. μηδείς (talk) 02:23, 27 August 2012 (UTC) Wow, all this, and nobody's yet pointed out that we do have a very thorough article called Free will. Red Act (talk) 03:39, 27 August 2012 (UTC) LOL, we can put this discussion into BJAODN. ibicdlcod (talk) 15:03, 27 August 2012 (UTC)

Okay, so without the relationship that we call conciousness (and, specifically, human conciousness or something very similar to it) there can be no entities that we call trees or rocks, in the same way as there can be no mathematics without conciousness. Gandalf61 (talk) 09:13, 28 August 2012 (UTC)

Briefly, things are what they are. So before minds existed, there were still what we call things. We can see that this must be the case because the universe evolved from the big bang and life evolved to produce animals and minds and mankind. What couldn't exist before minds existed was the mental categories of things, such as entities versus attributes, in abstraction. Mathematics is abstraction. All of the mathematical relations that held between things before there were minds to identify them still held. But they held in reality itself, not as numbers, which are concepts--symbols, in effect--that we use to grasp those proportions. Consider the problem of finding the longest piece of dry spaghetti. You can get a ruler and measure each one according to some unit and identify the largest number corresponding to the length of one of the pieces of spaghetti. Or you can stand them in a glass with a flat bottom, and the one that stands tallest is the longest. The first means requires a mind that does math. The second doesn't. (Although obviously glasses and spaghetti are products of beings with minds--but this is just an example.) The result is the same in each case, because the underlying reality is the same. But the math requires a mind. To say that the math itself is the underlying reality is at best a mind game. μηδείς (talk) 17:13, 28 August 2012 (UTC)

A vital read in this discussion (which is much more about philosophy than science, but whatever) would be Existence precedes essence, which discusses the philosophical conundrum of which comes first: whether something exists first and aquires meaning after it existance, or whether something needs to be defined before it says it exists. There are differing schools of thought as to which makes sense. --Jayron32 17:34, 28 August 2012 (UTC)

Thanks, Jayron. I have been wondering if there was an article like that. μηδείς (talk) 19:12, 28 August 2012 (UTC)

μηδείς, how do you know that there was a time when consciousness did not exist? if it does not fit in the physical universe now, then I would assume that it never did.165.212.189.187 (talk) 19:31, 28 August 2012 (UTC)

So far as we understand scientifically (and not imagine), minds and consciousness are faculties and properties of a certain type of living being. Based on quite a bit of evidence, I am willing to attribute consciousness to animals as simple as all birds and mammals and even octopuses, if not fish. But I have no evidence that there was consciousness when there were only single-celled organisms, and absolutely not before life existed. One has to provide prima facie evidence for something, else it is just an arbitrary assertion. As Hitchens asserts, "What can be asserted without proof, can be dismissed without proof." μηδείς (talk) 20:26, 28 August 2012 (UTC)

Absence of evidence is not evidence of absence... --TammyMoet (talk) 08:14, 29 August 2012 (UTC)

If you cannot even remotely explain consciousness with physics then how can you say that consciousness is entirely contained in our physical world? We know more about black holes than we do about what is between our ears. I love how physicists freely throw around ideas like "other universes in other dimensions" when talking about black holes or dark energy/matter way out there in space, yet when it comes to something so close to us as our consciousness physicists get constipation of the brain. occams razor could easily explain that those other dimensions thier math is probing/detecting could be our consciousness or the past or future.165.212.189.187 (talk) 14:19, 29 August 2012 (UTC)

Tammy, I am not exactly sure of what you are implying by your statement. IP 165, I am not quite sure I get your point either. I take the term physical universe to mean the realization that all existence exists in relation to bodies, and the theory that bodies are comprised of particles. That is fine. But neither music nor shadows are bodies or are comprised of atoms, although they do supervene on the atomic. See supervenience and this article on supervenience at the Stanford Encyclopedia of Philosophy. Consciousness may be highly mysterious, but it is no more unreal or supernatural than are music or shadows, which are also relational existents, not entities. μηδείς (talk) 01:49, 30 August 2012 (UTC)

Physicists can explain music and shadows with physics, duh. Did you not read my comment? MMM, yes, I propose that there are, uh, invisible only partially detectible dimensions that only partially interact with our world, yes, entire universes in fact! that's the ticket! I would say that sounds alot like a description of consciousness.165.212.189.187 (talk) 12:48, 30 August 2012 (UTC)

What aspect of consciousness does that sound a lot like ? Sean.hoyland - talk 12:55, 30 August 2012 (UTC)

Just off the top of my head: Through our bodies our consciousness, which can contain a vast amount of information, is able to interact with the physical world (only partially) but we could never manifest a "consciousness" into a physical tangible thing. We each have a consciousness = multiple universes. "There is something else "out there" but we cant explain it."165.212.189.187 (talk) 12:59, 30 August 2012 (UTC)

Excerpt from a scientists journal: I was studying these atoms in my microscope and all of a sudden they began to thrash about in unison and with what musicians call a "rhythm". THis is unexplainable. what is causing them to do this? Answer: THe person whose body contained those atoms was dancing to "Call me maybe". So it must be Carly rae Jepsen!165.212.189.187 (talk) 14:27, 30 August 2012 (UTC)

If by manifesting into a physical tangible thing, IP 165 means appear as a body, neither music nor shadows do that. If he means be observable, we are aware of our own consciousness and the consciousness of others, and can measure it with electro-encephalograms and other imaging equipment. Nor am I aware of any phenomena like vision that has been studied by scientists that needs positing ghosts from the aethereal plane (nowadays they call it the multiverse) to cover some part "physicists" can't "expalin with physics". I am not sure any point more coherent than "duh" can be extracted from what was said. μηδείς (talk) 17:58, 30 August 2012 (UTC)

That was the most important point anyway. Can you explain the origin of consciousness with physics? Please address my post of 12:59, as it relates to occams razor.165.212.189.187 (talk) 18:19, 30 August 2012 (UTC)

You don't seem to have understood a word I have said so far. You cannot have a coherent theory of consciousness without an understanding of metaphysics, and the realization that not everything is itself a body. Consciousness is not a thing separate from the thing which is one's body. Just like weight is real but not a thing, and just like weight exists as a relationship between a body and the earth, consciousness is a relationship between a certain type of living being and its environment. Consciousness no more works "through our bodies" than do shadows or weight. It is not something separate or detachable from the body, and certainly has no agency separate from the body. There is no more consciousness before, outside, and separate from the body than there is a shadow which exists before, outside and separate from the body. To demand an explanation of consciousness (an emergent biological phenomenon) on the level of physics--i.e., in terms of mass and velocity--is a profound category mistake. μηδείς (talk) 05:56, 31 August 2012 (UTC)

Weight and shadows do not actively consume energy like a consciousness does. So then all human consciousness is no different than a sunflower moving with the sun, or in other words no more than instinct?165.212.189.187 (talk) 14:11, 31 August 2012 (UTC)

Consciousness is not something over and above brain activity. Any energy expended is expended by the brain metabolism, not by some weird force called consciousness over and above the brain activity. The notion of consciousness as a thing separable from the body goes back to the ancient notion that your life is your breath (the word anima literally means "breath") consisting of a cloud of air that can escape the body when you die. There is no spirit molecule or spirit energy above or separable from the body.

Consider poison. Poisonous substances are not poisonous because they have, in addition to, say, carbon and nitrogen atoms, a certain number of Poisonium atoms in their molecular formula, or because they vibrate at a toxic frequency, or because they emit poisonous Phoitons. The molecule itself is poisonous due to its nature in a certain context, even though the individual atoms that make it up aren't poisonous and it doesn't have any "poison energy". The same with consciousness. There is no Conscionium atom, or Sodium Conscionol molecule, or even Master Consciousness Neuron. See homunculus argument and representationalism. There is just the innervated creature itself, one of whose attributes due to its nature in a certain context is that it is conscious.

Rather than an instinct, consciousness appears to be a harmonic relationship that exists due to the complex rhythmic firing of neurons, a sort of music of the brain induced in it by the environment similar to the way one vibrating tuning fork will induce vibration in another. That's a scientific theory, not something a philosopher is entitled to claim is true a priori. But the relational nature of entrainment (see Entrainment (physics), Entrainment (biomusicology), Brainwave entrainment) is compatible with the relational nature of consciousness. μηδείς (talk) 17:11, 31 August 2012 (UTC)

If a body reverses direction, does it momentarily stop?

If I throw a ball up into the air, at the apex of its flight before beginning its descent, is the ball motionless or is it constantly either moving up or down? Ankh.Morpork 18:38, 28 August 2012 (UTC)

If a ball is thrown straight up and follows the same path down as it does up, its instantaneous velocity will be zero at the apex. If the ball has any kind of arc, the horizontal component of the velocity will remain constant (subject to slight slowing due to air resistance, usually ignored for spherical cows) while the verical component of the velocity will be zero for an instant. Note that this is a literal instant, there is no measurement of time small enough over which the ball is not in some sort of absolute motion. However, when you reduce the time scale between measurements to zero, there will be a time, right at the apex, where the instantaneous velocity is actually zero. This takes some calculus to understand better, but if you know calculus, what that means mathematically is that the first derivative of the vertical position function of the balls path will be zero at the point in the path where the ball starts its decent. --Jayron32 18:44, 28 August 2012 (UTC)

Can you help me understand why when a fly flies horizontally into an oncoming car and then travels in the opposite direction squashed on the windscreen, there can be a period while the fly is motionless, since as soon as it makes contact, it would begin to move in the opposite direction ? Ankh.Morpork 19:09, 28 August 2012 (UTC)

Certainly. If you picture the fly's velocity towards the windshield and express it as simple scalar quantity, say we define the motion of the fly as positive numbers, therefore any motion in the opposite direction could be expressed as negative numbers. So, lets say the fly is going at +1 meter/second and a car is coming along at a speed (defined by our convention) at -10 meters/second. The fly would then have to change its velocity from +1 meters/second to -10 meters/second. You can't travel between the number +1 to -10 without passing through the number 0, so at some point the fly's velocity will be actually zero. This, remember, is a measure of instantaneous velocity and not average velocity. There is no period of time when the fly is not moving (that is, if we actually watch the fly, there is no two times, t₁ and t₂ between which the fly is not in motion. However, there will be a specific instant of time, in the limit where t₂-t₁ = 0 (that is, where no time passes) that the fly will have an instantaneous velocity of zero. This is a lot easier to understand with some rudimentary calculus under your belt, but even without it, I think my example above of the fly needing to get from a speed of +1 meters/second to -10 meters/second should work. Does it? --Jayron32 19:32, 28 August 2012 (UTC)

Thank you for your explanation. Can you reconcile "at some point the fly's velocity will be actually zero." with "there is no period of time when the fly is not moving" as not being mathematically adept, I don't quite understand this important distinction. The cross-over from a positive to a negative velocity must surely occur at a specific point in time, and if the fly is in constant motion, how do these two facts correlate? Ankh.Morpork 19:55, 28 August 2012 (UTC)

Sure. Picture a movie about the fly's motion which is say, one second long. At no point in that film will the fly not be moving. Now, picture a movie that is 0.1 seconds long. At no point in that movie will the fly not be moving. Now, picture a movie that is 0.000001 seconds long. At no point will the fly not be moving. Do you see what I am doing? I'm making the time span when I start and stop the movie recorder smaller and smaller. As long as there is an actual movie, there will be actual motion. Now, what calculus allows us to do is to consider the situation of the 0 second movie. Not 0.1. Not 0.0000001. Not even 0.0000000000000000001 second movie, but an actual 0 time movie. See, even in a 0 time movie, the fly is still in motion, we've just stopped the film at an instant. It is a bit like pausing the film and asking "At what speed is the fly moving in this still frame" For nearly all points in time, the fly will have a non-zero velocity. However, in the transition when he changes direction from forwards to backwards, on a single frame of that film, his velocity will actually be zero. This is an idealized film, however, where each frame is an infinitely small moment of time after the next (not a real film, where each frame has a gap when it isn't recording anything). In calculus, we call this the instantaneous rate of change and it is the rate of change of a function where the domain over which you are measuring the function is reduced to a single point. Does that work? If not, I have more analogies and examples. --Jayron32 20:06, 28 August 2012 (UTC)

OK I understand (I think) that for any period of time there will be motion, but yet for a specific time frame - the O time, the frozen film - the fly is capable of having a velocity of zero. I confess I still can't wrap my head around this concept so will bother you with some inane questions.

• Doesn't this this 0 time occur within a period of constant motion? On a velocity-time graph, doesn't the line intersect the time axis at a specific point while the fly is in motion?
• Why doesn't the fly have zero velocity in the transition of forwards to more forwards because so too, at every specific time frame, the fly is motionless. You can pause a movie whenever you want to and when you do all the frames are still - sorry if I'm taking the analogy to literally. Ankh.Morpork 20:33, 28 August 2012 (UTC)
  • Think of plotting a fly's velocity on a number line and watching a video of the dot travel along the number line as the fly's velocity changes. When the fly changes from moving forward to moving backwards (or the opposite), and only at that time will the dot cross the "zero" point on its trips up and down the number line. If the fly were traveling forward at 5 m/s and then was slowed constantly to 3 m/s or sped up to 8 m/s, it never actually crosses the zero velocity point. It is only when the sign of the velocity changes that you cross zero, so it is only in events that cause the sign to change (i.e. from forward to backward) that make the instantaneous velocity of the fly zero at any one point. Also, you misread the explanation a bit. In any specific "frame" of the film, the fly does have a velocity. It is only in the one singlular frame that captures the exact instant when he's transitioning from forwards to backwards when his instantaneous velocity is actually zero. --Jayron32 21:59, 28 August 2012 (UTC)

Maybe if its an incompressible spherical fly. lol. Isn't there a time when the front half of the fly is going backward while the back half is still going forward?165.212.189.187 (talk) 19:46, 28 August 2012 (UTC)

bsolutely. That's why they say that the last thing to go through a fly's mind when it hits a windshield is its ass.--Shantavira|^{feed me} 20:17, 28 August 2012 (UTC)

• This seems like a very basic question. The trajectory of the ball when it comes back down is exactly the same as if you'd released it from a stationary position at the exact moment when it reached the highest point. So yes, the ball stops after it goes up, and it falls exactly like a stopped ball would. Wnt (talk) 14:20, 29 August 2012 (UTC) (ignoring, I suppose, the tiny whoosh of air that comes up at it from the place it passed through on the way up)

• The sun seemingly stops and reverses direction twice a year, relative to the celestial equator. That's why the term "solstice" is used: "sun stands still". ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:50, 30 August 2012 (UTC)

Historical alternatives to Darwinism (AKA Darwinian evolution)?

This question lies between history and science.

So far, I can only think of Larmarckism and Saltationism. How do they become unsupportable? What information supports Darwinism and fails to support the other two theories of evolution? What is the difference between acclimitization of an individual to the environment and Larmarckism? Do people fail to support Saltationism because changes in populations can only occur one step at a time and not all together (i.e. organ systems can not just pop out of nowhere but must build on something as a template)? Any other alternatives or is that all? Does Biblical creation suggest that all living creatures on earth just pop out of nowhere? Wouldn't the central idea of Biblical creation be closer to the meat experiment in which bugs would grow in the open jar but not the closed jar because creatures would only reproduce after their own kind and not just pop out of nowhere? If that is the case, then didn't that scientist failed to support Biblical creation (sorry, I can't say "reject"; I say "support" or "fail to support"; I could have also used "fail to reject" and "reject"; I do not say "accept" or "reject" because those terms are not equal), which suggested that creatures would just pop out of nowhere under given nutritious conditions instead reproducing after their own kind? 21:05, 28 August 2012 (UTC) — Preceding unsigned comment added by 140.254.226.201 (talk)

I count seven questions there. If you ask seven questions at once on a Ref desk, all you get is disorganized chaos. Could you try to distill this down to one or two questions that matter most, and then ask the others later? Looie496 (talk) 21:36, 28 August 2012 (UTC)

Some historical alternatives to Darwinian evolution in roughly chronological order:

• Creationism
• Lamarckism
• (Darwin qua Darwin goes here)
• Theistic evolution
• Saltationism
• Mutationism
• Biometric evolutionism (Karl Pearson, Walter Frank Raphael Weldon, to some degree Sir Francis Galton)
• Modern evolutionary synthesis (not strictly identical with Darwin qua Darwin)
• Punctuated equilibrium (which is not strictly Darwinian)
• Intelligent Design

As for what leads to one or another, there are the short (somewhat wrong) answers (e.g. "Lamarckism was disproved by August Weissman when he observed that cutting off the tails of mice did not produce mice with shorter tails" — even Weissman knew that under orthodox Lamarckism this would not produce a result) and longer (somewhat dull) answers (like Peter J. Bowler's long but somewhat dry book, Evolution: The History of an Idea). The short version is, when you correlate all of the different types of data — observational, fossilized, genetic — the modern evolutionary synthesis (neo-Darwinism, or Darwinian evolution plus modern population genetics) still comes out on top.

There are many forms of Creationism; some are quite magical ("God woke up one day and said, let's have some giraffes"), some are more naturalistic (e.g. theistic evolution or intelligent design, in which God is either driving evolution or just occasionally intervening when things get hard). In the case of things popping out of nowhere, the actual popping in and out of existence is assumed to be miraculous and not subject to experimentation. --Mr.98 (talk) 22:14, 28 August 2012 (UTC)

Lamarckism fails for two reasons. There is no experimental confirmation. (I don't remember what experiments were actually tried, but, for example, cutting the tails of mice would not, after any long number of generations, result in a trend toward shortening tails.) Second, there is no mechanism to encode a physical change back into the genome. Causality goes in one direction only, genes > proteins > development > form and not the other way around. This question does seem like a homework question. μηδείς (talk) 01:20, 29 August 2012 (UTC)

Classical Lamarckism required a "vital force" within the animal — it doesn't happen from just external forces, but was the result of "striving" by the animal itself. So the cutting off of the tail experiment was something of a canard. That doesn't make it correct, of course. Similarly, there are some cases that the central dogma doesn't cover, e.g. epigenetics. --Mr.98 (talk) 02:25, 29 August 2012 (UTC)

But was the mouse experiment itself ever done? I know that experiments were done. As for striving, I never heard that dark or light skin was caused by striving, just due to tanning or the lack of. μηδείς (talk) 02:55, 29 August 2012 (UTC)

Weissman did cut off mouse tails, yes (68 mice, then all of the tails of their children for five generations). But such a thing would not have convinced a hardened Lamarckian. Again, Lamarck qua Lamarck has vital forces as the main mover. It's incredibly vague in many ways, and it's not super surprising that even Darwin himself was somewhat Lamarckian in his own hereditary proposals. The lambasting of Lamarck in the mid-20th century — which is the source of all of the current biology textbooks — is as much meant as a covert lambasting of Lysenkoism as anything else. There is a funny Cold War dynamic to biological heredity which not a lot of people know about; it's one of the reasons the people who worked on extranuclear inheritance were treated like pariahs for a long time. There is a terribly dull book on this that I'd be happy to recommend if anyone is interested... --Mr.98 (talk) 12:43, 29 August 2012 (UTC)

Actually there is a physical mechanism: proteins -> gene activation/repression -> histone methylation/acetylation/etc. -> DNA methylation -> CpG transition mutations. But you'd still need some circulating hormone to transfer a specific signal to the gonads. A higher level of growth hormone, triggered by environmental circumstances favoring larger animals in one generation, leading to mutations in genes affecting physical size - maybe. I don't know of any proof of such things, but I'm suspicious (for example, successful species tend to get larger, and humans have inexplicably gotten taller lately -though that could more likely be epigenetic based on the two preceding steps) But a signal to say "OMG my tail's been chopped off"? Probably not. Though you never really know until you try... Wnt (talk) 03:02, 29 August 2012 (UTC)

That's extremely technical, of doubtful use to a layman, and still doesn't amount to actual change in gene sequence caused by reverse design--just a rather random from the viewpoint of the phenotype environmentally induced change in gene expression.

Here's a paper on cutting off Daphnia antennae from 1931: A LAMARCKIAN EXPERIMENT INVOLVING A HUNDRED GENERATIONS WITH NEGATIVE RESULTS μηδείς (talk) 03:11, 29 August 2012 (UTC)

• In case anyone isn't aware, I'll mention that Lamarckianism, in the form of "inheritance of acquired characteristics", has indeed been verified in some lineages. Though not available to charismatic macrofauna, Horizontal_gene_transfer_in_evolution is an important non-Darwinian feature of evolution that is broadly accepted in modern science. SemanticMantis (talk) 04:16, 29 August 2012 (UTC)

Good catch. Though aphids are sort of charismatic... and prone to more than one kind of more-or-less Lamarckism... and the things they do with their carotene... ! [2] Wnt (talk) 20:37, 29 August 2012 (UTC)

Horizontal gene transfer is not non-Darwinian, it's non-Mendelian. And it doesn't result from an acquired adaptation of the adult to its environment (like a stretched neck) being coded back into a change in the gene sequence coding for that preadaptation. μηδείς (talk) 01:36, 30 August 2012 (UTC)

Well, the aphids host organisms, then acquire some of their genes. That seems close to that. Of course, arguing over what a centuries-old notion would mean in terms of modern evidence is sort of quixotic. Wnt (talk) 15:03, 30 August 2012 (UTC)

But horizontal transfer like this lies somewhere between viral infection and freaky sex in its mechanism, and the result is purely darwinian, a "random" recombination of genes leading to an undesigned change that may or may not be successful. It has nothing to do with the organism acquiring some characteristic from its environment and causing a directional change in its genome. Its basically sensationalism and publicity seeking at best, and just plainsloppy thinking at worst, for scientists to say this sort of thing. The "logic" goes: Lamarckism is a weird theory of evolution. This is a weird evolutionary phenomenon. Hence this phenomenon is (kinda like) Lamarckism. That's the same sort of logic you get from the press: Space aliens and are weird creatures. This decaying raccoon corpse is weird. Hence this corpse is a space alien. See sympathetic magic. Scientists shouldn't engage in that sort of "thinking". μηδείς (talk) 17:14, 30 August 2012 (UTC)

Horizontal gene transfer has everything to do with an organism acquiring a characteristic from the environment, and then passing it on to offspring. Simply put, an offspring can have traits that the parent was not born with. You are right to say that it is non-Mendelian, and that is a sharper point. And it this phenomenon is not at odds with simple natural selection per se, as you describe, it fits in nicely. But HGT is most certainly not a phenomenon addressed by classical Darwinian theory. It is one of the reasons why we use terms like "modern evolutionary synthesis". Unless you are writing a research paper in evolutionary dynamics, it is perfectly acceptable to say that HGT is a mechanism that can allow for inheritance of acquired characteristics. SemanticMantis (talk) 17:09, 31 August 2012 (UTC)

No. one's parents are "in the environment". But getting their genetic characteristics by Mendelian inheritance is simply not Lamarckism. Acquired characteristics are characteristics one gets not from sex or transfer of genes but from environmental influence. Your claim is simple nonsense I won't debate with. μηδείς (talk) 22:07, 31 August 2012 (UTC)