Time: Do the past, present, and future exist all at once?
Does time exist? Here's what the debate is all about.
MICHELLE THALLER: Is time real or is it an illusion? Well, time is certainly real but the question is what do we mean by the word time? And it may surprise you that physicists don't have a simple answer for that.
JAMES GLEICK: Physicists argue about and physicists actually have symposia on the subject of is there such a thing as time. And it's also something that has a traditional in philosophy going back about a century. But, I think it's fair to say that in one sense it's a ridiculous idea. How can you say time doesn't exist when we have such a profound experience of it first of all. And second of all we're talking about it constantly. I mean we couldn't get, I can't get through this sentence with out referring to time. I was going to say we couldn't get through the day without discussing time. So, obviously when a physicist questions the existence of time they are trying to say something specialized, something technical.
BILL NYE: Notice that in English we don't have any other word for time except time. It's unique. It's this wild fourth dimension in nature. This is one dimension, this is one dimension, this is one dimension and time is the fourth dimension. And we call it the fourth dimension not just in theoretical physics but in engineering. I worked on four dimensional autopilots so you tell where you want to go and what altitude it is above sea level and then when you want to get there. Like you can't get there at any time.
GLEICK: Einstein or maybe I should say more properly Minkowski, his teacher and contemporary, offers a vision of space-time as a single thing, as a four dimensional block in which the past and the future are just like spatial dimensions. They're just like north and south in the equations of physics. And so you can construct a view of the world in which the future is already there and you can say, and physicists do say something very much like this, that in the fundamental laws of physics there is no distinction between the past and the future. And so if you're playing that game you're essentially saying time as an independent thing doesn't exist. Time is just another dimension like space. Again, that is in obvious conflict with our intuitions about the world. We go through the day acting as though the past is over and the future has not yet happened and it might happen this way or it might happen that way. We could flip a coin and see. We tend to believe in our gut that the future is not fully determined and therefore is different from the past.
DEAN BUONOMANO: If the flow if time, if our subjective sense of the flow of time is an illusion we have this clash between physics and neuroscience because the dominant theory in physics is that we live in the block universe. And I should be clear. There's no consensus. There's no 100 percent agreement. But the standard view in physics is that, and this comes in large part from relativity, that we live in an eternalist universe, in a block universe in which the past, present and future is equally real. So, this raises the question of whether we can trust our brain to tell us that time is flowing.
NYE: In my opinion time is both subjective and objective. What we do in science and engineering and in life, astronomy, is measure time as carefully as we can because it's so important to our everyday world. You go to plant crops you want to know when to plant them. You want to know when to harvest them. If you want to have a global positioning system that enables you to determine which side of the street you're on, from your phone you need to take into account both the traditional passage of time that you might be familiar with watching a clock here on the Earth's surface, and the passage of time as it's affected by the speed of the spacecraft, and the passage of time as it's affected by the gravity of the Earth itself, both special and general relativities. It's astonishing. We work very hard to measure time with all sorts of extraordinary clocks, but there is no question with our brains which are wet chemical computers we lose track of time. We don't know if sometimes it feels short, sometimes it feels long and it's just the nature I think of being constrained by measuring time with our brains. This is why we build instruments to measure time outside of ourselves externally.
BUONOMANO: The brain has been telling time since the dawn of animal species. So even plants have the ability to tell time in terms of Circadian clock. So it's reasonable to ask so is that how the brain tells time? Does the brain have some oscillator that's ticking away and some circuit that's counting those ticks and tocks. The answer is no. The brain seems to have fundamentally different ways of telling time. So the first thing to notice is that while the mechanical clocks that we make, even your quartz watch, can tell time across a vast range of scales from tens of milliseconds to hours, minutes and days and months and years. So, the brain has many different clocks in order to tell the milliseconds and seconds and to tell the time of day. So one way to think about it is the Circadian clock, the clock that tells you what time of day it is and when to rise and when to go to sleep. That doesn't have a minute hand, much less a second hand. In contrast, the clock that tells you, the timing device in your brain that tells you hmm, this red light is taking a bit too long to turn. This traffic light is taking a bit long to turn or I think the waiter forgot my coffee. That clock doesn't have an hour hand, much less a number of days that have gone by. So the brain has different areas, different mechanisms in order to tell time. We don't understand, fully understand how the brain tells you what the tempo is a song is or when the red light is going to change. But it doesn't seem to have to do with any oscillator counter mechanisms. It seems to do with neural dynamics which is the fact that patterns of neurons, neurons are coupled to each other, neurons are connected to each other. And when you activate some neurons that group of neurons can activate another group of neurons which can activate another group of neurons. So you can have these evolving patterns of neural activity. So, this is consistent with what we call the multiple clock principle which is the brain doesn't have any master clock. It has many different circuits, each specialized or that focuses on processing time on one scale or another.
THALLER: One thing we are absolutely sure of is that the rate of time does change. Time is not just simply a progression like a river that keeps flowing. It can change depending on how fast you're moving through space and this is Einstein's special Theory of Relativity. The idea is that the faster you go, the slower time appears to be moving for you if other observers look at you going by. As you go faster and faster and approach the speed of light your time slows down more and more. And the amazing thing is that at the speed of light time does not progress at all. There are more everyday applications to this too. For example, the global positioning satellites that allow you to take your location from your smartphone. Those satellites are going overhead very, very fast. They're going nearly 20,000 miles an hour. And it turns out that that's fast enough that their time is slowed down. They're actually in a slightly different timeframe than we are. And we have to account for that. We have to correct for that mathematically. Otherwise, you would not get the right location. So, we know that time slows down. We observe this happening all around us. It was a really hard thing in modern physics about a hundred years ago for people to let go of the idea that time just has a rate that it flows. That, in fact, it can flow at different rates for different observers. Then there's the question of what is time related to space. And you may have heard that Einstein talked about a concept called space-time. He didn't believe that space and time were separate things. We certainly perceive them differently in our human brains. We can move through space, but time always seems to go just in one rate and in one direction. But Einstein thought they were part of a fabric, they were woven together. And one of the ways he illustrated this was that you have to adjust space and time so they always kind of balance out. If I am not moving through space, I'm sitting here still in this chair, then time just seems to go forward at a natural rate and time just flows. But if I start going faster and faster, my time slows down. So, in a sense I'm moving through space very fast so I can't move through time as fast as I might have. The two balance each other, space-time. If you move through space very fast time begins to slow down. And now something gets even stranger and that is that Einstein thought that the beginning of the universe, the Big Bang, created all of space and all of time at once in a big whole something. So every point in the past and every point in the future are just as real as the point of time you feel yourself in right now. Einstein believed that literally. One of his best friends died and he wrote a letter to this person's wife talking about how his friend still exists. Time is a landscape and if you had the right perspective on the universe you would see all of it laid out in front of you. All past, present, and future as a whole thing. And he said, you know, your husband, my friend, is just over the next hill. He's still there. We can't see him where we are now, but we are on this landscape with him and he still exists just as much as he ever has. Einstein believed that you right now had been dead for trillions of years, but you haven't been born yet. That everything that's happened to you if you could get the right perspective on the universe you could see all at once.
BUONOMANO: The present is the notion is that only the present is real. The past was real, the future some configuration of the future universe will be real, but for now only the present is real. In contrast the opposing view is called eternalism. Eternalism you have the past, present and future are all equally real. So, that makes the present just an arbitrary point in time or an arbitrary moment in time. So one way to think about this is now is to time as here is to space. So in the same sense that I happen to be here and some viewers are out at some other point in space and we're all comfortable with that notion that other points in space are equally real, in eternalism you have to be comfortable with the notion that other moments in time are as equally real as this moment in time and this is just an arbitrary moment.
GLEICK: And so if a physicist comes to me and says do some readjustment. Face it, the future looks different from the past to you, but actually physics tells us it's the same. I at least acknowledge that I have an obligation to take that seriously, to listen to it. And physicists do argue about these things and it's fair to argue about it.
THALLER: So modern physics has required us to really let go of the idea of time as something that just flows. We can measure that it's changing around us all over the place – satellites, particle accelerators, anything going fast. And it may be that space and time are the same thing all wrapped up together and it all exists all at once.
- Everything we do as living organisms is dependent, in some capacity, on time. The concept is so complex that scientists still argue whether it exists or if it is an illusion.
- In this video, astrophysicist Michelle Thaller, science educator Bill Nye, author James Gleick, and neuroscientist Dean Buonomano discuss how the human brain perceives of the passage of time, the idea in theoretical physics of time as a fourth dimension, and the theory that space and time are interwoven.
- Thaller illustrates Einstein's theory of relativity, Buonomano outlines eternalism, and all the experts touch on issues of perception, definition, and experience.
- From Science Fiction to Physics: Does Time Actually Exist? - Big Think ›
- New controversial theory: Past, present, future exist simultaneously ... ›
- Time Might Not Exist Outside of Our Minds, Propose Scientists - Big ... ›
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The COVID-19 pandemic is making health disparities in the United States crystal clear. It is a clarion call for health care systems to double their efforts in vulnerable communities.
- The COVID-19 pandemic has exacerbated America's health disparities, widening the divide between the haves and have nots.
- Studies show disparities in wealth, race, and online access have disproportionately harmed underserved U.S. communities during the pandemic.
- To begin curing this social aliment, health systems like Northwell Health are establishing relationships of trust in these communities so that the post-COVID world looks different than the pre-COVID one.
COVID-19 deepens U.S. health disparities<p>Communities on the pernicious side of America's health disparities have their unique histories, environments, and social structures. They are spread across the United States, but they all have one thing in common.</p><p>"There is one common divide in American communities, and that is poverty," said <a href="https://www.northwell.edu/about/leadership/debbie-salas-lopez" target="_blank">Debbie Salas-Lopez, MD, MPH</a>, senior vice president of community and population health at Northwell Health. "That is the undercurrent that manifests poor health, poor health outcomes, or poor health prognoses for future wellbeing."</p><p>Social determinants have far-reaching effects on health, and poor communities have unfavorable social determinants. To pick one of many examples, <a href="https://www.npr.org/2020/09/27/913612554/a-crisis-within-a-crisis-food-insecurity-and-covid-19" target="_blank" rel="noopener noreferrer">food insecurity</a> reduces access to quality food, leading to poor health and communal endemics of chronic medical conditions. The U.S. Centers for Disease Control and Prevention has identified some of these conditions, such as obesity and Type 2 diabetes, as increasing the risk of developing a severe case of coronavirus.</p><p>The pandemic didn't create poverty or food insecurity, but it exacerbated both, and the results have been catastrophic. A study published this summer in the <em><a href="https://link.springer.com/article/10.1007/s11606-020-05971-3" target="_blank">Journal of General Internal Medicine</a></em> suggested that "social factors such as income inequality may explain why some parts of the USA are hit harder by the COVID-19 pandemic than others."</p><p>That's not to say better-off families in the U.S. weren't harmed. A <a href="https://voxeu.org/article/poverty-inequality-and-covid-19-us" target="_blank" rel="noopener noreferrer">paper from the Centre for Economic Policy Research</a> noted that families in counties with a higher median income experienced adjustment costs associated with the pandemic—for example, lowering income-earning interactions to align with social distancing policies. However, the paper found that the costs of social distancing were much greater for poorer families, who cannot easily alter their living circumstances, which often include more individuals living in one home and a reliance on mass transit to reach work and grocery stores. They are also disproportionately represented in essential jobs, such as retail, transportation, and health care, where maintaining physical distance can be all but impossible.</p><p>The paper also cited a positive correlation between higher income inequality and higher rates of coronavirus infection. "Our interpretation is that poorer people are less able to protect themselves, which leads them to different choices—they face a steeper trade-off between their health and their economic welfare in the context of the threats posed by COVID-19," the authors wrote.</p><p>"There are so many pandemics that this pandemic has exacerbated," Dr. Salas-Lopez noted.</p><p>One example is the health-wealth gap. The mental stressors of maintaining a low socioeconomic status, especially in the face of extreme affluence, can have a physically degrading impact on health. <a href="https://www.scientificamerican.com/index.cfm/_api/render/file/?method=inline&fileID=123ECD96-EF81-46F6-983D2AE9A45FA354" target="_blank" rel="noopener noreferrer">Writing on this gap</a>, Robert Sapolsky, professor of biology and neurology at Stanford University, notes that socioeconomic stressors can increase blood pressure, reduce insulin response, increase chronic inflammation, and impair the prefrontal cortex and other brain functions through anxiety, depression, and cognitive load. </p><p>"Thus, from the macro level of entire body systems to the micro level of individual chromosomes, poverty finds a way to produce wear and tear," Sapolsky writes. "It is outrageous that if children are born into the wrong family, they will be predisposed toward poor health by the time they start to learn the alphabet."</p>Research on the economic and mental health fallout of COVID-19 is showing two things: That unemployment is hitting <a href="https://www.pewsocialtrends.org/2020/09/24/economic-fallout-from-covid-19-continues-to-hit-lower-income-americans-the-hardest/" target="_blank" rel="noopener noreferrer">low-income and young Americans</a> most during the pandemic, potentially widening the health-wealth gap further; and that the pandemic not only exacerbates mental health stressors, but is doing so at clinically relevant levels. As <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7413844/" target="_blank" rel="noopener noreferrer">the authors of one review</a> wrote, the pandemic's effects on mental health is itself an international public health priority.
Working to close the health gap<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDc5MDk1MS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxNTYyMzQzMn0.KSFpXH7yHYrfVPtfgcxZqAHHYzCnC2bFxwSrJqBbH4I/img.jpg?width=980" id="b40e2" class="rm-shortcode" data-rm-shortcode-id="1b9035370ab7b02a0dc00758e494412b" data-rm-shortcode-name="rebelmouse-image" />
Northwell Health coronavirus testing center at Greater Springfield Community Church.
Credit: Northwell Health<p>Novel coronavirus may spread and infect indiscriminately, but pre-existing conditions, environmental stressors, and a lack of access to care and resources increase the risk of infection. These social determinants make the pandemic more dangerous, and erode communities' and families' abilities to heal from health crises that pre-date the pandemic.</p><p>How do we eliminate these divides? Dr. Salas-Lopez says the first step is recognition. "We have to open our eyes to see the suffering around us," she said. "Northwell has not shied away from that."</p><p>"We are steadfast in improving health outcomes for our vulnerable and underrepresented communities that have suffered because of the prevalence of chronic disease, a problem that led to the disproportionately higher death rate among African-Americans and Latinos during the COVID-19 pandemic," said Michael Dowling, Northwell's president and CEO. "We are committed to using every tool at our disposal—as a provider of health care, employer, purchaser and investor—to combat disparities and ensure the <a href="https://www.northwell.edu/education-and-resources/community-engagement/center-for-equity-of-care" target="_blank" rel="noopener noreferrer">equity of care</a> that everyone deserves." </p><p>With the need recognized, Dr. Salas-Lopez calls for health care systems to travel upstream and be proactive in those hard-hit communities. This requires health care systems to play a strong role, but not a unilateral one. They must build <a href="https://www.northwell.edu/news/insights/faith-based-leaders-are-the-key-to-improving-community-health" target="_blank" rel="noopener noreferrer">partnerships with leaders in those communities</a> and utilize those to ensure relationships last beyond the current crisis. </p><p>"We must meet with community leaders and talk to them to get their perspective on what they believe the community needs are and should be for the future. Together, we can co-create a plan to measurably improve [community] health and also to be ready for whatever comes next," she said.</p><p>Northwell has built relationships with local faith-based and community organizations in underserved communities of color. Those partnerships enabled Northwell to test more than 65,000 people across the metro New York region. The health system also offered education on coronavirus and precautions to curb its spread.</p><p>These initiatives began the process of building trust—trust that Northwell has counted on to return to these communities to administer flu vaccines to prepare for what experts fear may be a difficult flu season.</p><p>While Northwell has begun building bridges across the divides of the New York area, much will still need to be done to cure U.S. health care overall. There is hope that the COVID pandemic will awaken us to the deep disparities in the US.</p><p>"COVID has changed our world. We have to seize this opportunity, this pandemic, this crisis to do better," Dr. Salas-Lopez said. "Provide better care. Provide better health. Be better partners. Be better community citizens. And treat each other with respect and dignity.</p><p>"We need to find ways to unify this country because we're all human beings. We're all created equal, and we believe that health is one of those important rights."</p>
Researchers make the case for "deep evidential regression."
- MIT researchers claim that deep learning neural networks need better uncertainty analysis to reduce errors.
- "Deep evidential regression" reduces uncertainty after only one pass on a network, greatly reducing time and memory.
- This could help mitigate problems in medical diagnoses, autonomous driving, and much more.
Credit: scharsfinn86 / Adobe Stock<p>On the road, 1 percent could be the difference between stopping at an intersection or rushing through just as another car runs a stop sign. Amini and colleagues wanted to produce a model that could better detect patterns in giant data sets. They named their solution "deep evidential regression."</p><p>Sorting through billions of parameters is no easy task. Amini's model utilizes uncertainly analysis—learning how much error exists within a model and supplying missing data. This approach in deep learning isn't novel, though it often takes a lot of time and memory. Deep evidential regression estimates uncertainty after only one run of the neural network. According to the team, they can assess uncertainty in both input data <em>and</em> the final decision, after which they can either address the neural network or recognize noise in the input data.</p><p>In real-world terms, this is the difference between trusting an initial medical diagnosis or seeking a second opinion. By arming AI with a built-in detection system for uncertainty, a new level of honesty with data is reached—in this model, with pixels. During a test run, the neural network was given novel images; it was able to detect changes imperceptible to the human eye. Ramini believes this technology can also be used to pinpoint <a href="https://www.theguardian.com/technology/2020/jan/13/what-are-deepfakes-and-how-can-you-spot-them" target="_blank">deepfakes</a>, a serious problem we must begin to grapple with.</p><p>Any field that uses machine learning will have to factor in uncertainty awareness, be it medicine, cars, or otherwise. As Amini says, </p><p style="margin-left: 20px;">"Any user of the method, whether it's a doctor or a person in the passenger seat of a vehicle, needs to be aware of any risk or uncertainty associated with that decision."</p><p>We might not have to worry about alien robots turning on us (yet), but we should be concerned with that new feature we just downloaded into our electric car. There will be many other issues to face with the emergence of AI in our world—and workforce. The safer we can make the transition, the better. </p><p>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a> and <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank" rel="noopener noreferrer">Facebook</a>. His new book is</em> "<em><a href="https://www.amazon.com/gp/product/B08KRVMP2M?pf_rd_r=MDJW43337675SZ0X00FH&pf_rd_p=edaba0ee-c2fe-4124-9f5d-b31d6b1bfbee" target="_blank" rel="noopener noreferrer">Hero's Dose: The Case For Psychedelics in Ritual and Therapy</a>."</em></p>
Can passenger airships make a triumphantly 'green' comeback?
Large airships were too sensitive to wind gusts and too sluggish to win against aeroplanes. But today, they have a chance to make a spectacular return.
What’s Eminem doing in Missouri? Kanye West in Georgia? And Wiz Khalifa in, of all places, North Dakota?
This is a mysterious map. Obviously about music, or more precisely musicians. But what’s Eminem doing in Missouri? Kanye West in Georgia? And Wiz Khalifa in, of all places, North Dakota? None of these musicians are from those states! Everyone knows that! Is this map that stupid, or just looking for a fight? Let’s pause a moment and consider our attention spans, shrinking faster than polar ice caps.
Vegans and vegetarians often have nutrient deficiencies and lower BMI, which can increase the risk of fractures.
- The study found that vegans were 43% more likely to suffer fractures than meat eaters.
- Similar results were observed for vegetarians and fish eaters, though to a lesser extent.
- It's possible to be healthy on a vegan diet, though it takes some strategic planning to compensate for the nutrients that a plant-based diet can't easily provide.
Comparison of fracture cases by diet group
Credit: Tong et al.<p>The results showed that vegans were especially vulnerable to hip fractures, suffering 2.3 times more cases than meat-eaters. Vegetarians and pescatarians were also more likely to suffer hip fractures, though to a lesser extent.</p><p>One explanation may be that non-meat eaters consume less calcium and protein. Calcium helps the body build strong bones, particularly before age 30, after which the body begins to lose bone mineral density (though consuming enough calcium through diet or supplement can <a href="https://ods.od.nih.gov/factsheets/Calcium-Consumer/" target="_blank">help offset losses</a>). Lower bone mineral density means higher risk of fracture.</p><p>Protein seems to help the body absorb calcium, <a href="https://www.bonejoint.net/blog/did-you-know-that-certain-foods-block-calcium-absorption/#:~:text=Historically%2C%20nutritionists%20have%20warned%20that,may%20increase%20intestinal%20calcium%20absorption." target="_blank" rel="noopener noreferrer">when consumed in normal levels</a>. The recent study, along with past research, shows that people who don't eat meat tend to have lower levels of both protein and calcium. When the researchers accounted for non-meat eaters who supplemented their diets with calcium and protein, fracture risk decreased, but still remained significant.</p>
Credit: Pixabay<p>Another explanation is body mass index (BMI). Non-meat eaters tend to have a lower BMI, which is associated with higher fracture risk, particularly hip fractures. In the new study, vegans with a low BMI were especially likely to suffer hip fractures. That might be because having more body mass provides a cushioning effect when people fall.</p><p>Still, the study has some limitations. For one, White European women were overrepresented in the sample. The researchers also didn't collect precise data on the type of calcium or protein supplementation, diet quality or causes of fractures.</p><p>Another complicating factor: Producers of vegan products, such as plant-based milk, are increasingly fortifying foods with nutrients like calcium and protein, so modern vegans are potentially at lower risk of deficiency.</p><p>The researchers wrote that their findings "suggest that bone health in vegans requires further research."</p>