Studying time’s arrow with philosophers

William D. Phillips: Time and Einstein in the 21st Century - video https://www.youtube.com/watch?v=X74TYKIz73k Using laser cooling to measure time - William D. Phillips - video http://bigthink.com/ideas/using-laser-cooling-to-mark-time In 1997 William D. Phillips won the Nobel Prize in Physics (together with Claude Cohen-Tannoudji and Steven Chu) for his contributions to laser cooling,,, He is one of three well-known scientists and Methodist laity who have involved themselves in the religion and science dialogue. The other two scientists and fellow Methodists are chemist Charles Coulson and 1981 Nobel laureate Arthur Leonard Schawlow http://en.wikipedia.org/wiki/William_Daniel_Phillips bornagain77

Sorry: Failing to describe the dimensions and measurements of a thought in scientific terms doesn't usually lead people to conclude that “thoughts do not exist”. Silver Asiatic

Seversky @ 10 I found that to be a thoughtful and worthwhile response - thanks.

But if you think there is some domain of existence that is neither matter nor energy – assuming that actually means something – then what is it? What is it made of? Why is it there? Why is it as you say it is? Asking questions, in a sense, is the easy bit. Coming up with answers is hard.

It seems that you're at least open to some possibilities that those questions could bring. Of course, if there is a domain of existence that is neither matter nor energy, we wouldn't expect direct scientific measures (since science is limited to matter and energy). We need other tools for research and we'd expect only indirect evidence. But this shouldn't be that difficult to accept. What is are physical dimensions of a thought? I think most of the world doesn't have a problem accepting that thoughts are immaterial. We know they exist by observing their effects. But we do not directly observe or measure them as if they are physical entities. Failing to describe the dimensions and measurements of a thought in scientific terms usually lead people to conclude that "thoughts do not exist". The point here is that, in my opinion, it's helpful to be open to the possibility that there is more to reality than what science can observe or measure directly. Silver Asiatic

The idea that time has a direction of motion (time's arrow) is one of the most persistent crackpot ideas in mainstream physics. Time cannot change by definition. Dr. Joe Rosen, the retired former physics chair of the University of Central Arkansas said it best:

What has been has indeed objectively been and is no more. What will be, objectively is not and has not been (and, in fact, is not even fully determined, according to quantum indeterminacy). All physical systems ride the universal wave of becoming. Any awareness (ours or that of other intelligences) of past and future reflects the objective wave of becoming. There is no problem of "the arrow of time." There simply is no arrow of time, as if time could go one "way" rather than another. That metaphor is an unfortunate result of spatializing time. The picture of time as a line along which one might travel in one direction or the other is a conceptual disaster. Time is becoming. Becoming is change. The undoing of a change is also a change. There is no "unbecoming. From "Time, c, and nonlocality: A glimpse beneath the surface?" Physics Essays, vol. 7, pp. 335-340, 1994

Mapou

The visible comes into existence from the invisible: Quantum Physics and Relativity 2: - Antoine Suarez PhD - video https://www.youtube.com/watch?v=jxuOE2Bo_i0&list=UUVmgTa2vbopdjpMNAQBqXHw bornagain77

"Everything we see around us, the world in which we live and of which we are a part, is made of matter and energy." That is a strict Materialist assessment, Seversky - and is not a given. Some view matter/energy as mediums for information, and Information is what it's all about. Others view matter/energy as emergent from Mathematics. ppolish

Silver Asiatic @ 9

I propose that materialism destroys philosophy since it eliminates the need to ask “why” about anything. There is no real meaning, only “outputs of processes”. Of course it is self-refuting because materialism is a philosophical position that cannot be established by physics (since physics is a philosophical concept itself).

I don't see that materialism eliminates the need to ask "why". We can always ask "why". As a materialist I could ask "why is matter and energy the way it is?" or that good, old favorite "why is there something rather than nothing?" Whether or not materialism is the complete answer, it's a good place to start. Everything we see around us, the world in which we live and of which we are a part, is made of matter and energy. How that explains the experiences of conscious beings such as ourselves is a hard one. I don't know. What I do know is that there is no evidence of a consciousness existing apart from a physical substrate like a brain. When a brain is destroyed, the conscious being associated with that brain is gone too. That alone suggests a strong connection between the two. It may not be intellectually or emotionally satisfying to some to believe that, at root, it is all nothing but matter and energy. It may even be objectionable. But that doesn't necessarily make it wrong - or right, come to that. But if you think there is some domain of existence that is neither matter nor energy - assuming that actually means something - then what is it? What is it made of? Why is it there? Why is it as you say it is? Asking questions, in a sense, is the easy bit. Coming up with answers is hard. Seversky

Scientists were known as natural philosophers before William Whewell coined the former term. If physicists have a problem with philosophers it’s only because they’ve lost touch with their roots.

Excellent point. But the question is - why have they lost touch with their roots? I propose that materialism destroys philosophy since it eliminates the need to ask "why" about anything. There is no real meaning, only "outputs of processes". Of course it is self-refuting because materialism is a philosophical position that cannot be established by physics (since physics is a philosophical concept itself). If biology is reducible to physics (as in materialism), then brain-activity (philosophy) is a product of a physical mechanism, fully explainable in terms of physics. Supposedly, we would be able to understand the origin of all human thought via chemical/physical processes. Silver Asiatic

As to the Time Dilation of relativity,,, Albert Einstein - Special Relativity - Insight Into Eternity - 'thought experiment' video https://vimeo.com/93101738 Time dilation Excerpt: Time dilation: special vs. general theories of relativity: In Albert Einstein's theories of relativity, time dilation in these two circumstances can be summarized: 1. --In special relativity (or, hypothetically far from all gravitational mass), clocks that are moving with respect to an inertial system of observation are measured to be running slower. (i.e. For any observer accelerating, hypothetically, to the speed of light, time, as we understand it, will come to a complete stop). 2.--In general relativity, clocks at lower potentials in a gravitational field—such as in closer proximity to a planet—are found to be running slower. http://en.wikipedia.org/wiki/Time_dilation Time Dilation | Einstein's Relativity - video https://www.youtube.com/watch?v=G-R8LGy-OVs ,,,There was a discrepancy found by Godel in the time dilation of relativity,,,

THE GOD OF THE MATHEMATICIANS - DAVID P. GOLDMAN - August 2010 Excerpt: Gödel's personal God is under no obligation to behave in a predictable orderly fashion, and Gödel produced what may be the most damaging critique of general relativity. In a Festschrift, (a book honoring Einstein), for Einstein's seventieth birthday in 1949, Gödel demonstrated the possibility of a special case in which, as Palle Yourgrau described the result, "the large-scale geometry of the world is so warped that there exist space-time curves that bend back on themselves so far that they close; that is, they return to their starting point." This means that "a highly accelerated spaceship journey along such a closed path, or world line, could only be described as time travel." In fact, "Gödel worked out the length and time for the journey, as well as the exact speed and fuel requirements." Gödel, of course, did not actually believe in time travel, but he understood his paper to undermine the Einsteinian worldview from within. http://www.firstthings.com/article/2010/07/the-god-of-the-mathematicians That discrepancy, found by Godel with relativity, was dealt with in the following study. the following study, through a fairly ingenious thought experiment, challenged the assumption of length contraction as being valid for 'photon clocks'. In doing so, they cleared up some loose ends in relativity concerning time's relation to space. Loose ends that had been ample fodder for much of the speculation of time travel being possible in relativity: Physicists continue work to abolish time as fourth dimension of space - April 2012 Excerpt: “The rate of photon clocks in faster inertial systems will not slow down with regard to the photon clocks in a rest inertial system because the speed of light is constant in all inertial systems,” he said. “The rate of atom clocks will slow down because the 'relativity' of physical phenomena starts at the scale of pi mesons.” He also explained that, without length contraction, time dilation exists but in a different way than usually thought. “Time dilatation exists not in the sense that time as a fourth dimension of space dilates and as a result the clock rate is slower,” he explained. “Time dilatation simply means that, in a faster inertial system, the velocity of change slows down and this is valid for all observers.,, Our research confirms Gödel's vision: time is not a physical dimension of space through which one could travel into the past or future.” http://phys.org/news/2012-04-physicists-abolish-fourth-dimension-space.html Of supplemental note: The Time Dilation of Relativity is VERY friendly to the Theistic concept of eternity:

"I've just developed a new theory of eternity." Albert Einstein - The Einstein Factor - Reader's Digest - 2005 "The laws of relativity have changed timeless existence from a theological claim to a physical reality. Light, you see, is outside of time, a fact of nature proven in thousands of experiments at hundreds of universities. I don’t pretend to know how tomorrow can exist simultaneously with today and yesterday. But at the speed of light they actually and rigorously do. Time does not pass." Richard Swenson - More Than Meets The Eye, Chpt. 12 It is also very interesting to note that this strange higher dimensional, eternal, framework for time, found in both special relativity and general relativity, finds corroboration in Near Death Experience testimonies: 'When you die, you enter eternity. It feels like you were always there, and you will always be there. You realize that existence on Earth is only just a brief instant.' Dr. Ken Ring - has extensively studied Near Death Experiences 'Earthly time has no meaning in the spirit realm. There is no concept of before or after. Everything - past, present, future - exists simultaneously.' - Kimberly Clark Sharp - NDE Experiencer 'There is no way to tell whether minutes, hours or years go by. Existence is the only reality and it is inseparable from the eternal now.' - John Star - NDE Experiencer 'In the 'spirit world,,, instantly, there was no sense of time. See, everything on earth is related to time. You got up this morning, you are going to go to bed tonight. Something is new, it will get old. Something is born, it's going to die. Everything on the physical plane is relative to time, but everything in the spiritual plane is relative to eternity. Instantly I was in total consciousness and awareness of eternity, and you and I as we live in this earth cannot even comprehend it, because everything that we have here is filled within the veil of the temporal life. In the spirit life that is more real than anything else and it is awesome. Eternity as a concept is awesome. There is no such thing as time. I knew that whatever happened was going to go on and on.' In The Presence Of Almighty God – The NDE of Mickey Robinson – video https://vimeo.com/92172680

bornagain77

All investigation is philosophy. natural philosophy because science recently only. its all about figuring things out. God and man became uninteresting after the success of natural things and attacks against God and mans special place. yet in reality god and man are studied greatly these days. the point is IS conclusions about nature any more settled in 'science' then other stuff. creationists know it ain't. Robert Byers

Agree BA77, and Dembski puts mathematics as a "thoroughly informational entity", a "medium for information". Both physical matter and mathematical matter are mediums for information per Dembski. Max needs to get up to speed:) ppolish

ppolish, actually Dembski has very impressive evidence, from quantum mechanics, that reality really is 'information theoretic', whereas Tegmark has no evidence for postulating a Platonic realm. Dr. Gordon puts the situation like this: BRUCE GORDON: Hawking’s irrational arguments – October 2010 Excerpt: ,,,The physical universe is causally incomplete and therefore neither self-originating nor self-sustaining. The world of space, time, matter and energy is dependent on a reality that transcends space, time, matter and energy. This transcendent reality cannot merely be a Platonic realm of mathematical descriptions, for such things are causally inert abstract entities that do not affect the material world,,, Rather, the transcendent reality on which our universe depends must be something that can exhibit agency – a mind that can choose among the infinite variety of mathematical descriptions and bring into existence a reality that corresponds to a consistent subset of them. This is what “breathes fire into the equations and makes a universe for them to describe.” Anything else invokes random miracles as an explanatory principle and spells the end of scientific rationality.,,, Universes do not “spontaneously create” on the basis of abstract mathematical descriptions, nor does the fantasy of a limitless multiverse trump the explanatory power of transcendent intelligent design. What Mr. Hawking’s contrary assertions show is that mathematical savants can sometimes be metaphysical simpletons. Caveat emptor. http://www.washingtontimes.com/news/2010/oct/1/hawking-irrational-arguments/ “In the whole history of the universe the laws of nature have never produced, (i.e. caused), a single event.” C.S. Lewis - doodle video https://www.youtube.com/watch?v=_20yiBQAIlk Of related note: Kurt Gödel - Incompleteness Theorem – video https://vimeo.com/92387853 THE GOD OF THE MATHEMATICIANS - DAVID P. GOLDMAN - August 2010 Excerpt: we cannot construct an ontology that makes God dispensable. Secularists can dismiss this as a mere exercise within predefined rules of the game of mathematical logic, but that is sour grapes, for it was the secular side that hoped to substitute logic for God in the first place. Gödel's critique of the continuum hypothesis has the same implication as his incompleteness theorems: Mathematics never will create the sort of closed system that sorts reality into neat boxes. http://www.firstthings.com/article/2010/07/the-god-of-the-mathematicians Taking God Out of the Equation - Biblical Worldview - by Ron Tagliapietra - January 1, 2012 Excerpt: Kurt Gödel (1906–1978) proved that no logical systems (if they include the counting numbers) can have all three of the following properties. 1. Validity ... all conclusions are reached by valid reasoning. 2. Consistency ... no conclusions contradict any other conclusions. 3. Completeness ... all statements made in the system are either true or false. The details filled a book, but the basic concept was simple and elegant. He (Godel) summed it up this way: “Anything you can draw a circle around cannot explain itself without referring to something outside the circle—something you have to assume but cannot prove.” For this reason, his proof is also called the Incompleteness Theorem. Kurt Gödel had dropped a bomb on the foundations of mathematics. Math could not play the role of God as infinite and autonomous. It was shocking, though, that logic could prove that mathematics could not be its own ultimate foundation. Christians should not have been surprised. The first two conditions are true about math: it is valid and consistent. But only God fulfills the third condition. Only He is complete and therefore self-dependent (autonomous). God alone is “all in all” (1 Corinthians 15:28), “the beginning and the end” (Revelation 22:13). God is the ultimate authority (Hebrews 6:13), and in Christ are hidden all the treasures of wisdom and knowledge (Colossians 2:3). http://www.answersingenesis.org/articles/am/v7/n1/equation# The God of the Mathematicians - Goldman Excerpt: As Gödel told Hao Wang, “Einstein’s religion [was] more abstract, like Spinoza and Indian philosophy. Spinoza’s god is less than a person; mine is more than a person; because God can play the role of a person.” - Kurt Gödel - (Gödel is considered one of the greatest logicians who ever existed) http://www.firstthings.com/article/2010/07/the-god-of-the-mathematicians bornagain77

It would not suprise me upon reading the full article that Tegmark does not put himself in the same boat as "most of his colleagues" when it comes to philosophy. This is the guy that says all of Nature is math - it's math all the way down. That's a bit metaphysical like Dembski's "matter is a myth" and it's information all the way down. I have not read his new book "Mathematical Universe" but I probably will. Sounds wild:) ppolish

Moreover, Tegmark's atheistic philosophy, (which he apparently is completely unaware of and is what is driving his bizarre, and untestable, multiverse metaphysics), leads to the epistemological failure of science instead of leading to the furtherance of scientific discovery.

Scientific Peer Review is in Trouble: From Medical Science to Darwinism - Mike Keas - October 10, 2012 Excerpt: Survival is all that matters on evolutionary naturalism. Our evolving brains are more likely to give us useful fictions that promote survival rather than the truth about reality. Thus evolutionary naturalism undermines all rationality (including confidence in science itself). Renown philosopher Alvin Plantinga has argued against naturalism in this way (summary of that argument is linked on the site:). Or, if your short on time and patience to grasp Plantinga's nuanced argument, see if you can digest this thought from evolutionary cognitive psychologist Steve Pinker, who baldly states: "Our brains are shaped for fitness, not for truth; sometimes the truth is adaptive, sometimes it is not." Steven Pinker, evolutionary cognitive psychologist, How the Mind Works (W.W. Norton, 1997), p. 305. http://blogs.christianpost.com/science-and-faith/scientific-peer-review-is-in-trouble-from-medical-science-to-darwinism-12421/ Why No One (Can) Believe Atheism/Naturalism to be True - video Excerpt: "Since we are creatures of natural selection, we cannot totally trust our senses. Evolution only passes on traits that help a species survive, and not concerned with preserving traits that tell a species what is actually true about life." Richard Dawkins - quoted from "The God Delusion" http://www.youtube.com/watch?v=N4QFsKevTXs “The multiverse idea rests on assumptions that would be laughed out of town if they came from a religious text.” Gregg Easterbrook Book Review: 'Our Mathematical Universe' by Max Tegmark Is our universe only one of many? If so, how real are the others? - Peter Woit - January 17, 2014 http://online.wsj.com/news/articles/SB10001424052702303393804579310720208417980 Multiverse and the Design Argument - William Lane Craig Excerpt: Roger Penrose of Oxford University has calculated that the odds of our universe’s low entropy condition obtaining by chance alone are on the order of 1 in 10^10(123), an inconceivable number. If our universe were but one member of a multiverse of randomly ordered worlds, then it is vastly more probable that we should be observing a much smaller universe. For example, the odds of our solar system’s being formed instantly by the random collision of particles is about 1 in 10^10(60), a vast number, but inconceivably smaller than 1 in 10^10(123). (Penrose calls it “utter chicken feed” by comparison [The Road to Reality (Knopf, 2005), pp. 762-5]). Or again, if our universe is but one member of a multiverse, then we ought to be observing highly extraordinary events, like horses’ popping into and out of existence by random collisions, or perpetual motion machines, since these are vastly more probable than all of nature’s constants and quantities’ falling by chance into the virtually infinitesimal life-permitting range. Observable universes like those strange worlds are simply much more plenteous in the ensemble of universes than worlds like ours and, therefore, ought to be observed by us if the universe were but a random member of a multiverse of worlds. Since we do not have such observations, that fact strongly disconfirms the multiverse hypothesis. On naturalism, at least, it is therefore highly probable that there is no multiverse. — Penrose puts it bluntly “these world ensemble hypothesis are worse than useless in explaining the anthropic fine-tuning of the universe”. http://www.reasonablefaith.org/multiverse-and-the-design-argument The Fine Tuning of the Universe - drcraigvideos - video https://www.youtube.com/watch?v=UpIiIaC4kRA Sean Carroll channels Giordano Bruno - Robert Sheldon - November 2011 Excerpt: 'In fact, on Lakatos' analysis, both String Theory and Inflation are clearly "degenerate science programs".',,, The sad part about Carroll’s piece, is that it confirms one of Jaki’s hypotheses–that what stopped the science of the golden age of Greece, what stopped the science of the Chinese or the Babylonians or the Caliphate was not politics, not anti-science reactionaries, not an epidemic of stupidity, but bad metaphysics. Bad metaphysics can turn any “progressive science program” into a “degenerate” one, and this infatuation with multiverses is sucking the life of hundreds of grad students, the resources of a hundred tenure-track cosmologists into the impossible task of predicting the unobservable. They’d be better off studying theology. http://rbsp.info/PROCRUSTES/sean-carroll-channels-giordano-bruno/ The Absurdity of Inflation, String Theory and The Multiverse - Dr. Bruce Gordon - video http://vimeo.com/34468027 Cosmic inflation is dead, long live cosmic inflation - 25 September 2014 Excerpt: (Inflation) theory, the most widely held of cosmological ideas about the growth of our universe after the big bang, explains a number of mysteries, including why the universe is surprisingly flat and so smoothly distributed, or homogeneous.,,, Paul Steinhardt of Princeton University, who helped develop inflationary theory but is now scathing of it, says this is potentially a blow for the theory, but that it pales in significance with inflation's other problems. Meet the multiverse Steinhardt says the idea that inflationary theory produces any observable predictions at all – even those potentially tested by BICEP2 – is based on a simplification of the theory that simply does not hold true. "The deeper problem is that once inflation starts, it doesn't end the way these simplistic calculations suggest," he says. "Instead, due to quantum physics it leads to a multiverse where the universe breaks up into an infinite number of patches. The patches explore all conceivable properties as you go from patch to patch. So that means it doesn't make any sense to say what inflation predicts, except to say it predicts everything. If it's physically possible, then it happens in the multiverse someplace Steinhardt says the point of inflation was to explain a remarkably simple universe. "So the last thing in the world you should be doing is introducing a multiverse of possibilities to explain such a simple thing," he says. "I think it's telling us in the clearest possible terms that we should be able to understand this and when we understand it it's going to come in a model that is extremely simple and compelling. And we thought inflation was it – but it isn't." http://www.newscientist.com/article/dn26272-cosmic-inflation-is-dead-long-live-cosmic-inflation.html?page=1#.VCajrGl0y00

Thus, perhaps if Tegmark were not so ashamed of being seen with Philosophers and Theologians in the first place, then perhaps he would not find himself spouting such unscientific multiverse nonsense of the highest order as he is currently doing? bornagain77

As to:

“To tell you the truth, I think most of my colleagues are terrified of talking to philosophers—like being caught coming out of a pornographic cinema,” says physicist Max Tegmark

Too Funny! ,,, Although I fail to see how multiverse popularizer Max Tegmark's amoral atheistic/materialistic philosophy would make him ashamed to be caught watching porno, I guess the only thing worse for an atheist such as Tegmark would be for him to be seen coming out of a church on sunday? :)

"For the scientist who has lived by his faith in the power of reason, the story ends like a bad dream. He has scaled the mountains of ignorance; he is about to conquer the highest peak; as he pulls himself over the final rock, he is greeted by a band of theologians who have been sitting there for centuries." God and the Astronomers (1978), p. 116; (p. 107 in 1992 edition) "Geoffrey Burbridge has lamented that his fellow scientists are rushing off to join the "First Church of Christ of the Big Bang."" Stephen Strauss, "An Innocent's Guide to the Big Bang Theory: Fingerprint in Space Left by the Universe as a Baby Still Has Doubters Hurling Stones," Globe and Mail (Toronto), April 25, 1992, p. 1.

Of related note:

Einstein and The Belgian Priest, George Lemaitre - The "Father" Of The Big Bang Theory – video https://www.youtube.com/watch?v=xhLQ_b3bKdI In January 1933, the Belgian mathematician and Catholic priest Georges Lemaitre traveled with Albert Einstein to California for a series of seminars. After the Belgian detailed his Big Bang theory, Einstein stood up applauded, and said, “This is the most beautiful and satisfactory explanation of creation to which I have ever listened.”

But actually, contrary to however ashamed Tegmark may feel about being seen with philosophers, (and I suppose he has an even worse aversion towards being seen with Theologians), science cannot be rationally practiced without first being grounded in Theistic metaphysics. Only Theism, Christian Theism in particular, presupposes an intelligibility to the universe, and that the human mind, being made in God's image, can grasp that intelligibillity.

Science and Theism: Concord, not Conflict* – Robert C. Koons IV. The Dependency of Science Upon Theism (Page 21) Excerpt: Far from undermining the credibility of theism, the remarkable success of science in modern times is a remarkable confirmation of the truth of theism. It was from the perspective of Judeo-Christian theism—and from the perspective alone—that it was predictable that science would have succeeded as it has. Without the faith in the rational intelligibility of the world and the divine vocation of human beings to master it, modern science would never have been possible, and, even today, the continued rationality of the enterprise of science depends on convictions that can be reasonably grounded only in theistic metaphysics. http://www.robkoons.net/media/69b0dd04a9d2fc6dffff80b3ffffd524.pdf The Threat to the Scientific Method that Explains the Spate of Fraudulent Science Publications - Calvin Beisner | Jul 23, 2014 Excerpt: It is precisely because modern science has abandoned its foundations in the Biblical worldview (which holds, among other things, that a personal, rational God designed a rational universe to be understood and controlled by rational persons made in His image) and the Biblical ethic (which holds, among other things, that we are obligated to tell the truth even when it inconveniences us) that science is collapsing. As such diverse historians and philosophers of science as Alfred North Whitehead, Pierre Duhem, Loren Eiseley, Rodney Stark, and many others have observed, and as I pointed out in two of my talks at the Ninth International Conference on Climate Change (ICCC), science—not an occasional flash of insight here and there, but a systematic, programmatic, ongoing way of studying and controlling the world—arose only once in history, and only in one place: medieval Europe, once known as “Christendom,” where that Biblical worldview reigned supreme. That is no accident. Science could not have arisen without that worldview. http://townhall.com/columnists/calvinbeisner/2014/07/23/the-threat-to-the-scientific-method-that-explains-the-spate-of-fraudulent-science-publications-n1865201/page/full Several other resources backing up this claim are available, such as Thomas Woods, Stanley Jaki, David Linberg, Edward Grant, J.L. Heilbron, and Christopher Dawson.

bornagain77

Scientists were known as natural philosophers before William Whewell coined the former term. If physicists have a problem with philosophers it's only because they've lost touch with their roots. As for the multiverse theory, as far as I understand it (which isn't much), the proponents argue that it seems offers a satisfactory solution to some of the hard problems they are trying to crack. They seem to be having a lot of fun playing with it, it's not doing anyone any harm that I can see, so why not leave them to it? If it's a dead end, they'll find out eventually but if they ever find evidence that it's true, it could be one of the biggest breakthroughs in science ever. Either way it's worth checking out. Seversky