Steven Weinberg - Why a Fine-Tuned Universe? 

Always a pleasure to listen to the great mind of Steven Weinberg

I appreciate Steven Weinberg's humility in presenting the puzzles which vex theoretical physicists. He presents the limitations on our knowledge of how the universe is, allowing for multiple possibilities.

One of your best episode’s. Thanks.

..." and matter will play a very little role "....🙏.... excellenty crisp and clear discourse... thank you...

Terrific! I actually understood what Weinberg was saying from first to last! Maybe I'm not as dumb as I thought. Or more likely he's so smart he can make himself understood to imbeciles like me.

Another excellent video from an excellent channel on yt. Just a small thing: please make it clear what is new material and old published long ago (obviously this one). Seems like old videos now being mixed with newer ones. A bit confusing, but should be easy to fix. But again: a lot to discover here!

Such a wonderful man.

It was a sad day when Steven Weinberg died. Physics lost a great man.

It’s criminal how few people know anything about Steven Weinberg

R.I.P. Mr. Weinberg. You were always a pleasure to listen to and a decent human being.

enjoyed that

Steven Weinberg was a great physicist

Amazing

The most logical explanation for the Fined tuned Universe is that we have one universal process from the quantum world of the very small to cosmology at the largest scale, with complexity arising out of simplicity.

This guy is a very smart man

In Hugh Everett's many-worlds interpretation of quantum wave function collapse, what determines, and more importantly, "when is it determined"- the split into another universe takes place?

Well rounded reasoning, i like his arguments.

It’s all about the sound.

Excellent q & a. S.W. was brilliant.

He was amazing man. Would have loved to have met him.

Fine tuning does not require a Fine Tuner.

If all space (actually "empty" or not) is filled with annihilating matter-antimatter pairs...why isn't measurable background gamma radiation ubiquitous?

I don't know if I'm just not getting this, but it sounds like he's asking this ... Why is the energy of empty space so seemingly insignificant (although collectively 70% of all the universe's energy), and alternatively, why is it not simply a flat zero? So, instead, should it be 0.1 x 10-¹⁰⁰⁰⁰? If you can't measure it, and you have to literally guess at what it "should" be, then maybe you just can't estimate it at all. May be it "should" be 0.1 x 10 to the minus infinity? Hmmm ... "zero point one times ten to the minus infinity" would be equal to "zero, but not zero" ... right? Kinda like the idea of multiplying by negative one. Basically absurd to calculate. And I still don't see the point of postulating an infinity of other universes to compensate for the incomprehensibility of God's mind.

Could quantum fields have gravitational attraction that nearly cancels their own expansion? Maybe 120 orders of magnitude energy in quantum fields is the denominator / base for 112 orders of magnitude time expanding space as numerator, leaving 10 power -8 cosmological constant?

what year was this made ?

Loved Steven's explanation of why the anthropic principle doesn't really add anything in the sense that it is either trivially true or a backwards explanation of the fact. I've always found the anthropic principle dissatisfying, but struggled to articulate exactly why - and this is coming from someone that isn't just wanting it to be a weak argument due to believing in god or something.

I like the tea kettle metaphor......

1. Universe has a cause. Why? Because every single thing we know of in the universe has a cause. It's not logical to conclude otherwise. 2. Super String Theory and all the variants of Multiverse theories don't at all explain existence, at best they explain the reason for energy, matter and life in the universe, not anything more than that. 3. It's not possible to explain existence because we are a part of it as are the tools we aim to use to answer the question. You cannot have part of the question as the answer. We can never get at the relationship of existence to non-existence because we can't "look" at it "from the outside" and the tools we have to use are part of that system too. I'm obviously meaning scientific observations utilizing math, physics and any other cognitive/technological system available to us.

Professor Mr. Weinberg mentioned planets 9. Is he including "Planet 9 or X" or referring to Pluto? Excellent video.

I wish we knew the date of the videos. You see Robert with dark hair and I know Steven Weinberg passed away in 2021.

I'm not a scientist but Steven Weinberg is my idea of who and what a scientist should be.

Fine tuning requires a prior intent to get certain results, which requires a previously existing mind, which cannot be validated by science or logic and is indistinguishable from fiction.

Why not

Saying that universe has find tuning, is like seeing in front of you and say Earth is Flat!!!

I've always wondered what happens at the edge of the universe, at the border of its expansion. What is that empty space beyond that borderline that is soon to become part of our universe?

If a multiverse explains fine tuning for life, what explains the fine tuning of the multiverse that enables some universe to b finely tuned? Is there an evidence for a multiverse? Is it falsifiable? Even if string theory would some day b proven correct. Wouldn't it just prove that one solution is true, not that other solutions are correct in other universes?

If space is omnipresent and omniscience it is not empty. We think of consciousness and intelligence in human brains but not in space which is supposedly empty.

The universe has no responsibility to explain itself, and it doesn't care that we want it to be explained.

👏👏👏

I don't see any link between the anthropic principle and postulating multiverses. We are not here due to any 'fine tuning' - we are here because we can be. And the universe is the way it is because that's the way it is. The whole fine-tuning argument is like throwing a handful of mud against a wall and then examining the resulting pattern and saying 'How amazing it is that the mud made THIS specific pattern! Of all the possible patterns it could have made, it made THIS amazing one! It must be a SPECIAL pattern! Hallelujah'

The multiverse not only describes concurrent universes but past as well. We are a point in (colloquially) infinite time.

Every number in the material universe can at best only approach zero, it can't be reached.

Of course there are multiple universes or why whould htere only be one? One thing about intelligent life, that probability is incredibly low, we think that a bilion is alarge number but in fact a bililon atoms is not very much, therefore there might be intellignet life only in some galaxies per universe.

Empty space energy is that of quantum fluctuation that is Planck fluctuations. Does it have mass ? Then this might be the dark matter if this energy applies to Einstein E= mc^2

Metaphysics Chip away the darkness and negative spaces and positive stuff emerges.

He’s very fair-minded about the anthropic principle, not dismissive of it altogether as you might expect an atheist like him to do. He’s willing to affirm it, albeit in a very narrow sense, if that sense has logical merit. This is a rational man !

There seem to be three distinct explanations of the problem of fine tuning. The problem: this universe is so incredibly "fine-tuned" to exactly the physical parameters necessary to permit life and human consciousness, that an explanation of the fine-tuning is needed. There are two better known explanations, and I'll add a third one that I came up with. Explanation 1: It is not strange that our universe has the exact parameters necessary to support life and human consciousness, because there are an infinite number of other universes whose parameters are different and do not support life and consciousness. In that infinity of universes, there are bound to be a tiny tiny percentage where the parameters are just those needed for life and consciousness to exist. Explanation 2: There are not an infinite number of other universes. To claim that there are is not a scientific claim, because other universes cannot possibly be observed. No, the reason our universe is so incredibly fine-tuned to the parameters that permit the evolution of life and consciousness is that our universe was designed with those incredibly precise parameters by a cosmic machinist, an engineer God. Explanation 3: This is my explanation, which probably others have come up with too, but I don't recall seeing my explanation elsewhere. According to Explanation 3, Explanation 1 is wrong, because there are not an infinite number of universes, at any rate that is not a testable hypothesis; but Explanation 2 is also wrong, because the universe is not merely a cosmic machine designed by a God who is merely an engineer setting parameters like dials on a machine. So here's Explanation 3: if the universe started out alive, or has always been alive at some fundamental level, then of course its parameters would be precisely those that life would need. In other words, the "fine-tuning" of our universe to support life is evidence that the universe's origin was a living origin. Matter and energy have taken on parameters so incredibly fine-tuned to life and consciousness because matter and energy were born from life, are "coagulates" of life, coagulates that formed over billions of years or more.

10:05 Weinberg is saying... “Why are we living at a time....”? - I assume “One has to first identify what is “living”!? Not just living, living....but aware of living livings”!? Science begone......!

I was wondering why my skull was so precisely fitted to my brain. NOW I know it's magic!

There are deeper laws and all constants are caused by them - that’s it.

Hees to smart four me two compreehend!

Even a dimwit like me appreciates the magnitude of this conversation

The concept , or more like the hypothesis of the multiverse was proposed by astute cosmologists who realized a very important problem in trying to explain the nature of the universe ; namely that the 'fine tuning' of the universal constants is so incomprehensibly precise that a random selection of those values to all intents and purposes precludes the possibility of a single exclusive universe imposing those values of the constants at its inception - at the very moment of its creation , unless there is an infinite creator. I like to quote a simple analogy. Suppose you place a bet on a national lottery where there might be 20 million other people who also place a bet. Your chances of winning would be in the order of many millions to 1 . Lets just assume its 20 million to 1. That means 1 chance in 2 times 10 to the power 6. You wouldn't go to sleep believing that you are VERY LIKELY to win the jackpot, but you would hope against hope that you might. Now if we take just one universal constant such as the cosmological constant ,'omega', if that had been different from its present value by 1 in 10 to the power 139 , the universe could not exist as we know it. That's like saying the chances of a 'successful' universe should have been less likely than you winning the lottery by an order of magnitude of 1 in 10 to the power 133 . By this reasoning , if one rejects the idea of an infinite creator , there is no choice but to require the existence of a multiverse. However there are strong compelling reasons why the multiverse concept can't really supply an answer to the mystery.

In the description "Coincidence and luck seem wildly unlikely" is nonsense. As pointed out so eloquently by Stephen Weinberg. We see randomness producing order everywhere in nature. Quantum states are by their very nature random and yet explain in detail the world around us. The multiverse doesn't seem a wildly unlikely scenario to me. Everything in nature comes in multiple instances. If you say that it's widely unlikely because there is no evidence, all I would say is well then so is a Tuner.

I could listen to Stephen all day. (You're looking younger by the way. Whatever it is you're doing, it appears to be working) 🙂.

Thanks good stuff a whole lot of pure speculation,,,and a simple we dont have the amswers!!!?

The true fine tuning is in the initial preset of reality. That preset whatever it was (quantum fields, energy, a banana, whatever) had to be incredibly fine tuned to give rise to a complex universe (With consciousness inside). And that preset was there because incredible luck or by an intelligent intent. No other options. Is also interesting that an atheist have ALWAYS to seek refuge into the multiverse theory to explain fin tuning.

The outcome of the whole discussion is "I/we don't know". Then what's the point of such discussion? The fact is ,there is no end of the chains of "Why?". Can you answer the question why you were born under your parents,instead of being born of a billionaire's parents? Why were you born in a country of your birth, instead of in Africa/ Syria/ Afghanistan? Can anyone explain/predict/identify why a particular sparm out of millions can ultimately penetrate an egg, starting at the dawn of a life? Similarly, you have to accept the fact that had there been no fine tuning of the different cosmological constant, the intelligent and conscious life of our form would not be possible on earth.😊🙏

With or without a multiverse we have a diminished ability to calculate things. The observer problem can be kept this simple. Nobody will discuss the obnoxious physical form of infinity that a world where I wrote 'dimished' above instead of 'diminished' leads. It's too much free lunch. Way, way, way too much.

I've always seen the anthropic principle as a statement in logic. Clearly, if physical constants are not fined tuned, then humans don't exist. This is a statement of the form A=>B (A implies B), which is logically equivalent to the statement not(B)=>not(A), which translates to the following: if humans exist, then physical constants are fine tuned . Here we recognize the anthropic principle.

The answers to our key questions are found within the data succinctly referred to as, the initial conditions-more precisely, its finely-tuned values-culminating to the Big Bang or, more correctly, the Beginning. TLDR: since it is highly unlikely (actually, "absurdly" so, to put it mildly, even flattering) to be from random processes then, logically, it is not and, therefore, by design-deliberate & intelligent design. Furthermore, postulating multiverses is even more highly & absurdly so unlikely, since the unlikelihood is exponentially compounded to way beyond comprehension! Just do the math! P.S. Interestingly (& coincidentally) the Bible begins with, "in the beginning." How did they/it know?

The vacuum catastrophe

when was this recorded? and what was the cause of Steven's dead?

I think I know what space is about, The solution is in the geometrical struktur, which is different, from what it appears to us...

If the average temperature of space is 4 degrees Kelvin, it's clear it's not empty. If it were empty, that temperature would be zero.

honest guy

It’s like saying a computer is dumb luck…. No it was built and obviously designed

ozone is earth boundary.?

Fascinating, but when Weinberg said "cubic feet" it felt like a punch in the gut.

Even if there is only one universe, we could not be here if things were set up in ways that didn't support our development. In our exploration of the universe, we are guaranteed never to find anything that prohibited our existence. It doesn't explain why things are set the way they are, but neither does positing infinite universes that vary in certain features.

To me this is the best take on that question that I've heard so far

Weinberg seems strangely comfortable to me in postulating a multiverse without any direct supporting evidence. His argument seems to rest strongly on string theory which itself has very little direct supporting evidence. From this rather meager position Weinberg feels he can offer a salutary answer to the anthropic principle.

Steve is my Jesus.

The multiverse sounds like the same type of explanation as the is a benevolent create. Maybe physicists have to admit they don’t know and maybe aren’t smart enough to figure it out.

"Look!", said the Puddle, "at how perfectly the ground fits me. It must be fine-tuned for my existence!"

If the universe were really fine tuned there would be no Evil.

"The anthropic principle is a retreat". Thank you\. "Otherwise there might actually be intelligence behind all this". God forbid.

One way to describe the human experience is monkeys posturing in the mirror.

Everybody knows that power can be projected through space, even space that contains gases such as our atmosphere. Is it only momentum that pushes particles through so-called empty space? I think that we need some new ideas in this area. I wonder why cosmologists and physicists have no problem positing black holes, gravity waves, and even multiple Universes or dimensions to make equations seem to work; yet the idea that there is no such thing as empty space never comes up. Perhaps it would be too glaring of an idea that would demand theories and thus show the state of understanding or lack thereof that erodes away the reputations of the experts. There is energy in the space between the atoms of our environment. It is just a continuation of the empty space of the Universe. How can particles and empty space be in the same place. It is that they locate there each in their own way, in a combination of complementary usage and some joint occupation. How particles, space, energy, and forces live together should be a fundamental area of inquiry. One final point: Why do we not suppose anything about the space that the Universe is expanding into? Perhaps some of the energy that we consider to be unique to our Universe or some other form may occupy the area of future expansion. That would certainly affect some well-established calculations. I think that it is philosophically and scientifically unwise to assume a nothing theory of an area outside of our Universe. It amounts to a simplification of the the idea that the Universe really does mean everything, not just what our best instruments and theories can engender. It does make sense to apply some reasonable limits to get useful results for our calculations; but negating a large something that is probably infinitely larger than our present expanding idea of the Universe is not a good idea if one actually wants to understand reality.

Their voices sound almost identical - kind of weird.

RIP

If time and space are infinite how can one explain how could you be here right now?

Long wandering discussions are one way of saying "We Do Not Know". We are here because if our universe was not fine-tuned then we would not be here. The question is random chance verses the existence of a "Tuner". I vote for dumb luck.

If you think fine tuning is easy, you haven't seen all the experimental universes that have never created anything worth integrating into the prime universe.

Every being is a universe that hasn't yet seen his or her own universe. The children of these age and doctors are disturbing the cause and effect of natural and spiritual growth.

Steven Weinberg claims the universe is just about balanced for humans to grasp the connection with cosmic consciousness, that every thing in the universe is for humanity to thrive. Although he is an atheist, his arguments implies that Anthropic principle is real.

Nice camera work, not

The so called fine tuning argument reminds me of how medieval philosopher's argued over how many angels could dance on the head of a pin. There are no angels and there is no tuning, fine or otherwise. We exist because we fit this universes parameters. It wasn't "tuned". We adapted .

BEWARE! The provider of this video is being deceptive. This exact video was streamed 6 years earlier in 2010. It was titled: "Steven Weinberg - How Many Universes Exist." Weinberg died July 2021, age 88. WAIT, it gets worse. This same video was first made even earlier. RU-vid revenues increase when viewers believe they're watching the latest! They know recent videos get more clicks. BTW, the very first "truly" original video was interesting.

A lot of physics average themselves out such as temperature for example. The Universe just averages itself out, and that is called fine tuning.

The Universe is Nothing close to 'fine-tuned'...!

The answer is. It would not have happened otherwise.

The universe is and will always be impossible to understand for human beings. Expanding into what ffs!

To further the understanding of theistic incompetence, we don't know if there is anything like intelligent life anywhere else (I'm not discounting that). Think of the possibilities of a laboratory as large as the Universe, then only creating "us" on an infinitesimally small speck within that lab. In other words, creating a lab the size of the State of Ohio and only creating life on a grain of sand - at just one particular time. C'mon

The human 'Mind' want's to be god. It will never ever be, because it was created, it is finite, it will go.

Two points. 1) A fine tuned universe'. That is a loaded phrase, or could too easily be considered a loaded phrase. Loaded with what? Loaded with implicit meaning. Loaded with assumptions. Like: like that the universe was created, instead of just began, and that it could have been created differently than it was. Smuggling in the God idea. The phrase is ambiguous. It doesn't have to mean this. It could be taken to refer to the situation of cosmological measurement and constants such that small changes in them would have resulted in a very different universe; a universe without life or a universe without black holes or a universe with.....ask a cosmologist. I regard the used of this ambiguity as an indication of attempting to smuggle mysticism into science. 2) So let 'fine tuning' have its mystical connotation. The question is then, What is a neutral phrase? The phrase has to recognize the specificity of the various parameters for the universe as it is and leave the door open for a natural or supernatural, or for that matter linguistic, explanation.

Hahaha, what if the so called fine-tuned universe is just a fine tuning fork of a singularity in a more fundamental reality than the universe that being projected from that singularity. That also means all fine-tuned stuff is just only those things that can resonant with this "almighty" singularity that projects this 3D universe + time.

2 most feared physicists (by votes) are Witten and Weinberg.

whst sbout photons passing through empty space

so they accept string theory as true now?