Subtitles section Play video Print subtitles If you had to choose right now, how long would you want to live? 80 years? 90? 120? Longer? And do you think you'll change your mind once you reach that age? Fifty thousand years ago most humans died very young. As we learned how to use the resources around us to treat ourselves, this got better and better. Today, humans are living longer and healthier lives than ever before. But this has an unforeseen consequence. We spend an ever-increasing part of our lives being sick and in need of care. Most of us will die in a hospital bed, which is depressing enough by itself. But we also have to witness the same happening to our loved ones. Except, maybe we can stop this forever. The most effective way to treat a disease is to prevent it. It saves many more lives if you stop a million people from smoking, than coming up with better chemo therapies. So why not put a halt to the cause of all disease: the process of aging. In a nutshell, aging is caused by physics, and not biology. Think of cars: Parts wear down from rubbing and grinding, metal rusts, filters get plugged, rubber cracks. Our bodies are worn down by trillions of tiny physical processes. Oxygen, radiation from the sun, our metabolism. Our bodies have many mechanisms to repair this damage, but over time they become less effective. So our bones and muscles weaken, our skin wrinkles, our immune system gets weaker. We lose our memory and our senses diminish. There's no such thing as dying of old age. We all die because one of our important parts breaks. The older we get, the more damaged and fragile we become until one or multiple diseases take over and kill us. Unnoticed by most of us, longevity research has made some unprecedented advances in the last few years. For the first time, we're starting to understand the mechanisms behind aging and how to manipulate them. Aging is neither mystical nor inevitable, and we might be able to stop or delay it during your lifetime. We'll discuss the science behind it and how scientists are trying to stop it in another video. But first, if we could, should we end aging? Is this a good idea? The end of aging or life extension makes many people uncomfortable. We're born, are young, become older, and then we die. This has been the natural order for literally all of human history, and getting old is a good thing, right? We celebrate the idea of living long enough to experience old age. We even call them the golden years. But the reality is that everybody wants to become old, but nobody wants to be old. Think of the Greek myth of Tithonus for example. Tithonus was the lover of the goddess Eos and probably an amazing dude. Because she begged Zeus to grant him immortality, so they could spend eternity together. But she forgot to specifically ask for eternal youth. Tithonus was granted eternal life, but he kept aging, unable to die. After a few hundred years, he was reduced to the size of a grape, babbling on senselessly forever. Thousands of years ago, humans already feared never-ending old age. But ending aging does not mean getting weaker and weaker. If you become too old, it's too late. A 90 year old who stopped aging would die anyway after a few years. Too much damage has been done to his internal machinery. There are already too many surfaces for disease to attack. Instead, the concept of life extension promises to end diseases, and with them, the end of a fixed maximum age. We don't know how much we could prolong our lives. We might make every human healthy to the currently accepted maximum age of around 120, or we might stop biological aging and disease indefinitely. Nobody knows at this point what's possible. Okay, but even if we could achieve that, should we? Well, life extension is really just another phrase for medicine. All the doctors are doing is trying to prolong life, and minimize suffering. The vast majority of healthcare resources are spent on the consequences of aging. Nearly half of your lifetime healthcare costs will be spent during your senior years, and another third during middle age. We are actually already trying to prolong life with our current medicine. We're just doing it very inefficiently. Trying to stop aging from happening is not less natural than transplanting a heart, treating cancer with chemotherapy, using antibiotics or vaccines. Nothing humans do nowadays is purely natural anymore, and we enjoy the highest standard of living ever as a consequence of that. What we're doing right now is waiting until it's too late and the machine is failing. And then we use the vast majority of our resources trying to fix it as well as we can, while it breaks down even further. But life extension still feels hubristic. Most people assume that they will want to die once they reach a certain age, and this might still be true. The idea of avoiding death entirely is off-putting for many. The end of biological aging would not be in the end of death in any way. It's more like a summer evening when you were a kid, and your mom called you inside. You just wanted to keep playing, have a little more fun during sunset before you went to sleep. It's not about playing outside forever, just a little longer, until we feel tired. If you imagine a world without disease where you and your loved ones could live in good health for another 100 or 200 years, how would this change us? Would we take better care of our planet if we knew we would be around longer? If we could work for 150 years, how much time would we spend figuring out what we're good at? How much more time would we spend learning? Would the intense feeling of pressure and stress many of us are feeling right now, go away or get worse? So asking again, if you could choose how long to live right now, in good health and with your friends and family, what's your personal answer? What would you like your future to look like? But maybe you're still unconvinced. Some nagging feeling remains. That is the Reaper whispering into your brain. Watch my video to hear what he says, and why you shouldn't listen. Your eternal future may depend on it. Go watch the other part over at CGP Grey's channel, and if you're not already subscribed, subscribe.