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What Is Aging? Most Scientists Still Get It Wrong

joshmitteldorf.scienceblog.com

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Re: What Is Aging? Most Scientists Still Get It Wrong

#121

Post by collyw »

ekianjo wrote: post #78
collyw wrote: post #71

Earlier quoted context omitted.

And the environment is currently being destroyed with the current population of 7 billion. Add another half again, and you think its all fine? And 97% of scientists agree that climate change is happening, and is probably caused by man.

> And 97% of scientists agree that climate change is happening, and is probably caused by man. You know, 97% of scientists believed that the Sun rotated around the Earth not too long ago, so "consensus" is rarely telling.

You are correct that they aren't entirely correct in their predictions. So far global warming has been greater than what they predicted a few years back.

Re: What Is Aging? Most Scientists Still Get It Wrong

#122

Post by [deleted] »

lars wrote: post #82
IndianAstronaut wrote: post #32

Earlier quoted context omitted.

We are not even close to discovering the cure for aging, so worrying about how it will change society is very premature. Until we can get a C eelegans worm to live for years, we are not remotely close to stopping aging.

I thought the entirety of the C. elegans 302 neuron neural network had been implemented in code. If we're able to implement accurate copies of them, we have effectively made them immortal. Scale this up to human brains, and we are immortal ourselves.

[deleted]

Re: What Is Aging? Most Scientists Still Get It Wrong

#123

Post by collyw »

lars wrote: post #82
IndianAstronaut wrote: post #32

Earlier quoted context omitted.

We are not even close to discovering the cure for aging, so worrying about how it will change society is very premature. Until we can get a C eelegans worm to live for years, we are not remotely close to stopping aging.

I thought the entirety of the C. elegans 302 neuron neural network had been implemented in code. If we're able to implement accurate copies of them, we have effectively made them immortal. Scale this up to human brains, and we are immortal ourselves.

You are making pretty big assumptions about neural networks and consciousness. When people are in a vegetative state after a bad accident, their brains are still functioning to some extent - but it hardly means they are living / conscious.

Re: What Is Aging? Most Scientists Still Get It Wrong

#124

Post by collyw »

ekianjo wrote: post #64
sanxiyn wrote: post #57

Earlier quoted context omitted.

This is not true. No amount of space suffices for exponential growth. Hubble length is less than 10^24 km. Earth radius is more than 10^3 km. Therefore there's at most room for 10^21 growth in one dimension, 10^63 growth in three dimensions. 10^63 growth is less than 210 doublings. Doubling is less than 70 years of 1% growth per year. 210 * 70 is less than 20,000. Therefore, we can't grow more than 20,000 years, 1% g…

who talks about exponential growth ? Ongoing growth can be linear and has no need to be exponential. Nice strawman.

The way politicians describe growth, it is implicit that it is exponential. More people, producing more offspring, living longer, and using more resources, as more of them become middle class.

Re: What Is Aging? Most Scientists Still Get It Wrong

#125

Post by mitteldorf »

mrfusion wrote: post #81
collyw wrote: post #66

Earlier quoted context omitted.

I started intermittent fasting around a year ago, and usually I do do reasonable amount of exercise. I had a health review as part of my work three months after I started. I really wanted to stop, because the fasting was difficult (I was doing two days a week). While before I was fairly healthy, my blood pressure has always been a bit high, as with my cholesterol. After fasting they were both gone down to good levels…

I'm strongly considering starting this. Any tips? (Feel free to email if you don't want to share publicly.)

The most important thing to keep in mind is that your own body is your best experimental lab, and that you should pay attention to what works FOR YOU and keep a diary. Other people's experience is good for giving you ideas of things to try, but people vary considerably, and you will find your own experience changes from week to week, as well as evolving over time.

Re: What Is Aging? Most Scientists Still Get It Wrong

#126

Post by mitteldorf »

UhUhUhUh wrote: post #99
gabriel34 wrote: post #96

The best explanation I found was on the book The Value of Tomorrow by Eduardo Giannetti, Brazilian philosopher and economist (in this chapter he had several consultants): If there is a trade-off between longer lifespan and reproductive capacity at a young age, there will also be a point of equilibrium. Suppose there was no senescence, we all lived perfectly healthy and at peak capacity for the duration of our lives.…

Yup. And the trade off between reproduction and aging is extremely well documented in biology. In short, reproduction prioritizes the set over the element. Kinda Borg-ish but that's what we have so far.

The tradeoff between reproduction and aging is sometimes present and sometimes absent. The successes are over-reported and the failures under-reported, so you might get the impression of "extremely well documented" with a cursory reading. Here is an example from Cynthia Kenyon's lab, "Healthy Animals with Extreme Longevity" http://www.sciencemag.org/content/302/5645/611.full

Re: What Is Aging? Most Scientists Still Get It Wrong

#127

Post by mitteldorf »

gabriel34 wrote: post #96

The best explanation I found was on the book The Value of Tomorrow by Eduardo Giannetti, Brazilian philosopher and economist (in this chapter he had several consultants): If there is a trade-off between longer lifespan and reproductive capacity at a young age, there will also be a point of equilibrium. Suppose there was no senescence, we all lived perfectly healthy and at peak capacity for the duration of our lives.…

This way of thinking assumes that all life is evolved for maximum reproductive fitness. This is false. It is bedrock evolutionary biology, but it is also false. It turns out that the way evolution works is much more subtle than the postulates of R. A. Fisher's system, which dominated evolutionary thinking during the 20th century. Here is a good read on the subject: http://aeon.co/magazine/science/why-its-time-to-lay-the-self...

Re: What Is Aging? Most Scientists Still Get It Wrong

#128

Post by mitteldorf »

jostmey wrote: post #103

My favorite explanation of Againg comes from William Hamilton. He took advantage of the Euler-Lotka equation to calculate the number of offspring that would be alive at any given point in the future. Using this equation from the field of demographics, he showed that senescence has only a marginal effect on fitness. As such, selective pressure would not be strong enough to filter out mutations that might result in agi…

Marginal effect on INDIVIDUAL fitness, but a huge effect on THE FITNESS OF ECOSYSTEMS. Without aging, ecosystems would be unstable dynamic systems, and would not last more than a single generation. Without aging, everyone would die at once, in famines and natural disasters. Aging is necessary to spread out the death rate, so that populations don't swing wildly up and down.

Re: What Is Aging? Most Scientists Still Get It Wrong

#129

Post by mitteldorf »

waps wrote: post #27
givan wrote: post #11

Aging is encoded in our DNA with a purpose, if we will be able to fully understand how DNA works me might be able to partially disable it but will we want to? maybe when we will reach that level of knowledge we will also have the wisdom to understand the implications.

That purpose may be "kill the old to make sure the world keeps changing, make sure new genetic experiements (ie. kids/offspring) get a chance". As we hopefully all know, nature isn't afraid to kill off a few people to get more useful experiments (how many animals die trying to have sex, for instance. That is not "necessary") Early animals didn't age, nor did they die. Some plants don't age (they still die due to illn…

I agree - take a look at http://www.amnat.org/an/newpapers/SepMitteldorf.html http://mathforum.org/~josh/Mitteldorf&Martins_Programmed-Agi...

Re: What Is Aging? Most Scientists Still Get It Wrong

#130

Post by halfcat »

collyw wrote: post #120
mrfusion wrote: post #91

Earlier quoted context omitted.

Thanks for the tips! Can you still work out on the fasting days or would that be ridiculous? Can you concentrate at work?

First few times is a bit tricky concentrating at work - actually I started feeling really high towards the end of the first evening. After two or three weeks its fine. Feels a bit more tired towards the end of the day - like you might after a long hike or something - pleasant tired, and want to go to bed an hour earlier than usual. I personally avoid exercise on the fast days, but some people swear by it (reddit has…

Did you normally get enough sleep before starting the fasting? You mention that you now get more sleep, and I wonder how much of a factor that is in improving your blood pressure and cholesterol.
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