gib65

Thinking about how we humans have been damaging the global ecosystem with our industrial prowess for the last few hundred years, we've definitely seen the devastating effects it can have on life forms which depend on the environment staying in its pre-industrial-revolution state. What I'm wondering, however, is how many people are of the opinion that this damage spells the doom for life altogether in the ecosystem in question such that once the damage is done, no life will be found there for an indefinite time? Because the theory of evolution would suggest an alternative scenario where life will simply adapt to suite its new environment. So, it is certainly the case that the current configuration of life in a particular environment will not survive an excess amount of damage, other configurations which thrive on the environment in such a "damaged" state will eventually sprout out. For example, if CO2 emissions continue to saturate the air at the rate it is currently at, oxygen breathing animals like ourselves will eventually die from suffocation, but with 6 billion people on Earth, there might be a small handfull who are genetically endowed with mechanisms in their respiratory system that can either tolerate CO2 or even make use of it somehow. Again, the general issue is: does environmental damage destroy life or change it? What do you think?

I think space and time exist in the sense that they are a "something" rather than a "nothing". GR suggests this since it speaks of space and time curving and bending. How can a big field of nothing curve and bend?

I'm not the authority on the subject, but my guess would be that 1) the expansion is happening to slowly to notice, and 2) that the gravitational bonds between the sun and the other planets in our solar system is strong enough to make the needed adjustments and extra space is "inserted" between them.

I Heard The Same Thing, but I don't know if I believe it. Why can't your brain just be surprised that you didn't die?

I had an idea. I want to know what people think of it: Do you think that one of the main reasons computer engineers have been having trouble mimicking the human brain is simply because computers are digital while brains are analogue?

Does anyone know of a chart that matches mood to the levels of certain neuro-chemicals in the brain. For example, I'm pretty cure (but I could be wrong) that happiness correlates with high levels of seritonin. Does anyone know what neuro-chemicals correlate with moods like depression, anger, love, guilt, fear, etc.? Even a reference to an on-line source would help. Thanks

Anybody?

Gilded is right, It's also note worthy to point out that once you dissect an atom, you're no longer dealing with matter proper. Now you've got electricity, proton beams (or energy fields), and the like. So the atom remain the smallest building block of matter.

I've heard two theories about how neurons change their interconnections with each other. I'm just wondering which one of them, or both of them, are true. 1) The dentrites of one neuron branch out and make connections with other nearby neuron on their axons. To change a connection, the dendritic branches physical move away from one neuron and connect to another one. 2) Dendritic branches do not move from/to other neurons' axons. Instead the receptors at the connection site change in quantity and type. So if at one site, there are a lot of one kind of receptor that readily reacts to a neurotransmitter that is readily emitted at that site, this site can be easily used to transmit signals from the one neuron to the other. To change this, the quantity of receptors reduces (or changes type), thereby making the recipient neuron less likely to fire when the sender neuron transmits a signal to it. Therefore, this site is no longer useful for transmitting signals. Are both these true? If not, which one is?

Ah! So it would NOT be unreasonable to assume everyday rigid object remain in the same positions and states as we saw them in before we turn away. Of course, weather or not they DO remain in these states cannot be verified empirically. Does this sound right.

I just finished watching What the Bleep Do We Know. There was that one scene in which the kid playing basket ball said of the ball that, before we observe it, it was in a state of superposition - that is, it was in a whole array of different positions (or, more accurately, its exact position was undefined). It was only upon observing the ball that it "collapses" into the position we see it in. Now, they made this out to seem like it was exclusively our perception of the ball that causes this collapse. But it leads me to wonder if there are other kinds of interactions that can lead to collapse, interactions that can go on outside the scope of our perception. For instance, would it be unreasonable to say that two particles somewhere in space where no observer perceives them, can be in states of superposition, and somehow their probability waves interact in such a way that they both collapse (or at least one of them does) into more precisely defined positions? Would it not be reasonable to say that a book sitting on your desk, or a coke sitting in your fridge is still, more or less, in a precise position (precise enough on a macroscopic scale) because all the molecules making it up are constantly interacting with each, being so closely interconnected, thereby bringing about their collapse so often that their probability waves have nearly no chance of expanding to a macroscopic range. In other words, the molecules themselves keep the whole object in a (more or less) precise position by constantly collapsing each other. If so, human perception is obviously not the only thing to bring about these wave function collapses. I think I can predict the answer to this question. I have a feeling someone will reply with "Well, if particles do collapse each other's wave functions beyond our observation, we could never know about it. We must observe in order to know." Fair enough. Then let me restate my question: Are there some (professionals, that is) who believe that perception is the only thing that brings about the collapse of the wave function, while others believe that the collapse can come about without observation? What are the reasons for and against either claim?

So then, I presume longer wavelengths, though poor at measuring position, are better for measuring momentum. But please explain how this works. How do longer wavelengths tell us more about a particles momentum and how does this effect the position?

I've been reading up on Heisenberg's Uncertainty Principle, and I've got a question about it. How does one measure the position of a particle such that it effects the momentum, and visa-versa? Does one effect the other regardless of the method used to measure them?

So if a particle was sitting there alone in space, and all of its properties are in a state of superposition, then over time it's field of probability should grow. That is, say you had a particle in position (x, y, z) at time t. If it's properties are in a state of superposition, which includes its momentum (velocity and direction), then at time t + n (where n is an arbitrary positive number) its' position could be anywhere within a certain radius around (x, y, z). Then at time t + 2n, its' position could be anywhere within twice that radius, and at time t + 3n, 3 times that radius, and so on. So isn't it true that its' range of probability propagates outward over time? Also, what does "interaction" mean in this case. Say you had a particle which you had more certainty as to its position and momentum, and you wanted to use it to measure the less certain particle. If the less certain particle is anywhere within a range of probability, what determines when and how your measuring particle will interact with it?

I have a question about how the wave function of particles collapses. I've heard that the wave function collapses when a particle interacts with another particle, but in the context of quantum mechanics, I'm not sure what "interact" or "collapsing of the wave function means". My understanding is as follows: The "wave function" is the perpetual propagation of the probability wave of a fundamental particle - a field of probability where the particle is most likely to be, and grows larger so long as no other particle interacts with it. Interaction in this case is kind of a fuzzy term since their positions are only probablistic. Is this understanding correct? Also, what would happen if a particle just sat there in empty space with no other particle for light years to interact with it? Would the probability wave perpetually expand even becoming macroscopic?

So, then, what if the universe itself is evolving? What if it has the potential to evolve into something that can actually alter its own laws such that the laws of entropy won't necessarily hold forever? I guess I'm stepping more into fantacy with that idea instead of scientific speculation, but it's interesting to ponder, isn't it?

I'm confused about something. I've been hearing that photons are massless, yet it is predicted that blackholes exist. The appearant contradiction here is that blackholes are predicted to exist because light is subject to gravity in the same way matter is. That is, light curves toward the source of gravity. They say that blackholes are objects with so much gravity that they do not let light escape (i.e. Light curves so much that it always ends up travelling directly towards the object's center of gravity). But how can light be influenced by gravity in this way if light, being composed of photons, is massless? Doesn't it require mass to be "heavy"?

Yes, yes, all very good, but what do the laws of entropy say about the fate of the universe (now that I know to distinguish between thermodynamic and structural entropy - thanks Les - I refer only to the structural type). Is the universe doomed to settle into a field of floating debri without much life to it at all, or is there hope that the universe could evolve into something greater from which it will never degrade, or at the very least continue forever in a state of equilibrium (with moderate fluctuations now and again). For instance, the idea that the universe will eventually collapse upon itself in a "Big Crunch", and then a "Big Band", and yet another "Big Crunch" after that, and so on, seems to me like a system that will never succumb to entropy. Or what about the Moon orbiting the Earth, or an electron orbiting a proton? Don't these represent systems in states of equilibrium such that the one body will continue to orbit the other indefinitely? I'm not a physicist, so I'm not trying to strike a blow at the theory of entropy. Just asking 'cause I wanna know.

Does the universe necessarily have to end in a state of disorder? I only ask because I've come to understand entropy to be a law that all physical systems succumb to eventually. But obviously, there are both entropic and "enthalpic" (thanks YT2095) processes in the universe. Why would the entropic processes prevail in the end? What about states of equilibrium?

I googled for "define: entropy" and came up with this: "A measure of the disorder in a system." I also entered "entropy" into http://www.dictionary.com and found, among other definitions: "The tendency for all matter and energy in the universe to evolve toward a state of inert uniformity." So if I understand this correctly, entropy is the phenomenon observed when, for instance, an elastic band goes from stretched to slack or a building going from erect to rubble when demolished by means of explosives. Is this correct? If so, what do we call the opposite phenomenon - that is, the building up of physical systems from something simple with uniformly distributed energy to something more complex and non-uniformly structured?

hm, very good points.

Very interesting reads. And now for my rebuke. First of all, with respect to Stefan Lovgren's article, there's a few quotes that seem to touch on the differences between computers and brains. A couple of the most relavant are... "Silicon-based computers are very accurate and fast at processing some kinds of information, but they have none of the flexibility of the human brain." and "Brains can easily make certain kinds of computations that computers are unable to do, such as answering open-ended questions about what happened sometime in the past." These, to me, point out some of the differences between computers and brains, but that should be expected. The comparison between brains and computers should not be confused with equating the two. At best, the brain is like a computer, and a computer is like a brain. Surely there will be differences. More specifically, this article points out how our current technology has yet to emulate some of the abilities the brain can accomplish, but this does not mean it never will, and if it does, there is no reason to assume it will have to apply principle above and beyond those of computational mathematics. Our lack of understanding how the brain accomplishes some of the amizing feats it does is no reason to throw the computer model out the window. It may still just come down to algorithms that we have not had the ingenuity to conjure up. Moreover, after reading this article, what with brains being connected to computers, being fed inputs and emitting outputs, controlling a flight simulator, etc., it seems the computer model is probably the most appropriate. With respect to Peter Dayan's article, I should humble myself as this writer seems a lot more eloquent than I can handle. He has a heavy vocabulary, and I admit I had to look up a few of the words, but if I understand the overall position he takes (and Hawking's), I'll just say that I don't quite understand how his article merits disposing of the computer model of the brain. I can see how the "unsupervised learning" model would make the "home PC" unfit as an analogy, but there are many different types of computers out there, and I can easily conceive of one whose main function is to extract statistical structures from inputs (it wouldn't even have to have a central processor). Furthermore, it's suprising how you selected this article since Dayan doesn't seem that keen on Hawking's ideas to begin with. If there are differences between brains and computers to be gleened from these articles, they are ones of specific algorithms. It is in how the brain computes the information it receives, and not that it computes information point blank. Overall, I'm not convinced. That's not to say I can't be. When I started this thread, what I was generally trying to ask was if there are any studies or evidence out there to support the idea that it requires more than just the phenomena of electric impulses traveling down the axons of neurons and chemicals crossing the synaptic gaps in order to explain the activity of the brain. Obviously, it would require more than this to explain consciousness, so never mind that for now. Let me restate the question: "Is the human brain a deterministically closed system? Any unassailable evidence for or against this?" And, honestly, I am open to good points on either side.

Artorius, Calling this thread "stupid" is a blatant oxymoron with the statement you made just a few sentences ago: "The human brain is so complex we are only now just starting out on the road to understanding the electrical impulses that take place." If it's so complex and beyond our comprehension, how could a thread discussing the topic be "stupid"? The fact that we have people posting opinions on both sides of the fences shows that we can't all be as ignorant about it as you seem to think. I don't think there's anyone here who thinks the workings of the brain in its entirety are "common knowledge" but there are some of us who think there is some common knowledge that explains some of the workings of the brain. If not, then all our neuroscientific progress (albeit, very little with respect to how much there is to gleen from the brain) has been made in vain. But if you get so "very angry" at some of the comments that are bound to be posted on such a hot topic, then, rather than making your problem our problem, maybe it would be best for all of us if you just made a good example of your own preaching and didn't post here. Quixix, I will be replying to your posts soon. Good reads, BTW.

A reference to Hawking's work would be nice. I google searched for Hawking exhaustively and could only find computers for sale from Hawking Technology and a quote from Stephen Hawkings about AI taking over the world. No it doesn't. I really don't think it's relavant though since 1) when someone brings up the concept of memory in a casual manner, without reference to implicit or explicit memory, it's fair to assume they mean explicit memory, and 2) even if they did mean to refer to implicit memory, the fact that it cannot be equated with knowledge sheds no light on the brain-computer analogy, which was the subject matter of the larger topic in this thread. Good for you for pointing it out though.