Monday, 30 July 2018

The Anthropic Principle: Was the Universe Made for Us?

Diagram on the dimensionality of spacetime, by Max Tegmark
Posted by Keith Tidman
‘It is clear that the Earth does not move, and that it does not lie elsewhere than at the center [of the universe]’ 
— Aristotle (4th century BCE)

Almost two millennia after Aristotle, in the 16th century, Nicolas Copernicus dared to differ from the revered ‘father of Western philosophy’. Copernicus rattled the world by arguing that the Earth is not at the center of the universe — in a move that to many at the time seemed to knock humankind off its pedestal, and reduce it from exceptionalism to mediocrity. The so-called ‘Copernican principle’ survived, of course, along with the profound disturbance it had evoked for the theologically minded.

Five centuries later, in the early 1970s, an American astrophysicist called Brandon Carter came up with a different model — the ‘anthropic principle’ — that has kept philosophers and scientists debating its significance cosmologically and metaphysically. With some irony, Carter proposed the principle at a symposium to mark Copernicus’s 500th birthday. The anthropic principle points to what has been referred to as the ‘fine-tuning’ of the universe: a list of cosmological qualities (physical constants) whose extraordinarily precise values were essential to making intelligent life possible.

Yet, as Thomas Nagel, the contemporary American philosopher, suggested, even the physical constants known to be required for our universe and an intelligent carbon-based life form need to be properly understood, especially in context of the larger-scaled universe:
‘One doesn’t show that something doesn’t require explanation by pointing out that it is a condition of one’s existence.’
The anthropic principle — its adherence to simplicity, consistency, and elegance notwithstanding — did not of course place Earth back at the center of the universe. As Carter put it, ‘Although our situation is not necessarily central, it is inevitably privileged’. To widen the preceding idea, let’s pose two questions: Did the anthropic principle reestablish humankind’s special place? Was the universe made for us?

First, some definitions. There are several variants of the anthropic principle, as well as differences among definitions, with Carter originally proposing two: the ‘weak anthropic principle’ and the ‘strong anthropic principle’. Of the weak anthropic principle, Carter says:
‘… our location in the universe [he was referring to the age of the universe at which humankind entered the world stage, as well as to location within space] is necessarily privileged to the extent of being compatible with our existence as observers.’
Of the strong anthropic principle, he explained,
‘The universe (and hence the fundamental parameters on which it depends) must be such as to admit the creation of observers within it at some stage’.
Although Carter is credited with coining the term ‘anthropic principle’, others had turned to the subject earlier than him. One in particular among them was the 19th-century German philosopher Arthur Schopenhauer, who presented a model of the world intriguingly similar to the weak anthropic principle. He argued that the world’s existence depended on numerous variables, like temperature and atmosphere, remaining within a very narrow range — presaging Carter’s fuller explanation. Here’s a snapshot of Schopenhauer’s thinking on the matter:
‘If any one of the actually appearing perturbations of [the planets’ course], instead of being gradually balanced by others, continued to increase, the world would soon reach its end’.
That said, some philosophers and scientists have criticized the weak variant as a logical tautology; however, that has not stopped others from discounting the criticism and favoring the weak variant. At the same time, the strong variant is considered problematic in its own way, as it’s difficult to substantiate this variant either philosophically or scientifically. It may be neither provable nor disprovable. However, at their core, both variants (weak and strong) say that our universe is wired to permit an intelligent observer — whether carbon-based or of a different substrate — to appear.

So, what kinds of physical constants — also referred to as ‘cosmic coincidences’ or ‘initial conditions’ — does the anthropic principle point to as ‘fine-tuned’ for a universe like ours, and an intelligent species like ours, to exist? There are many; however, let’s first take just one, to demonstrate significance. If the force of gravitation were slightly weaker, then following the Big Bang matter would have been distributed too fast for galaxies to form. If gravitation were slightly stronger — with the universe expanding even one millionth slower — then the universe would have expanded to its maximum and collapsed in a big crunch before intelligent life would have entered the scene.

Other examples of constants balanced on a razor’s edge have applied to the universe as a whole, to our galaxy, to our solar system, and to our planet. Examples of fine-tuning include the amount of dark matter and dark energy (minimally understood at this time) relative to all the observable lumpy things like galaxies; the ratio of matter and antimatter; mass density and space-energy density; speed of light; galaxy size and shape; our distance from the Milky Way’s center; the sun’s mass and metal content; atmospheric transparency . . . and so forth. These are measured, not just modeled, phenomena.

The theoretical physicist Freeman Dyson poignantly pondered these and the many other ‘coincidences’ and ‘initial conditions’, hinting at an omnipresent cosmic consciousness:
‘As we look out into the universe and identify the many accidents of physics and astronomy that have worked together to our benefit, it is almost as if the universe must in some sense have known we were coming.’
Perhaps as interestingly, humankind is indeed embedded in the universe, able to contemplate itself as an intelligent species; reveal the features and evolution of the universe in which humankind resides as an observer; and ponder our species’ place and purpose in the universe, including our alternative futures.

The metaphysical implications of the anthropic principle are many. One points to agency and design by a supreme being. Some philosophers, like St. Thomas Aquinas (13th century) and later William Paley (18th century), have argued this case. However, some critics of this explanation have called it a ‘God of the gaps’ fallacy — pointing out what’s not yet explained and filling the holes in our knowledge with a supernatural being.

Alternatively, there is the hypothetical multiverse model. Here, there are a multitude of universes each assumed to have its own unique initial conditions and physical laws. And even though not all universes within this model may be amenable to the evolution of advanced intelligent life, it’s assumed that a universe like ours had to be included among the infinite number. Which at least begins to speak to the German philosopher Martin Heidegger's question, ‘Why are there beings at all, instead of nothing?’

13 comments:

Martin Cohen said...

"Did the anthropic principle reestablish humankind’s special place? Was the universe made for us?"

I've always thought this rather a silly question. As has been quickly noted, if the universe we live in was NOY suitable for human beings... then we wouldn't be here to admire it. Freeman Dyson seems to reflect this confusion too, as described here.

That said, Keith and others?, the sheer complexity of phenomena that seem to have combined coincidentally to make life on earth possible (the creation of the moon, for example at a very specific size and time) does make me wonder about the unique circumstances that created us.

Keith said...

You point out, Martin, that “if the universe we live in was NOT suitable for human beings ... then we wouldn't be here to admire it.” Others, as you know, have certainly made the same observation in discussions of the anthropic principle. You go on to conclude, interestingly, that the question “Was the universe made for us?” is “silly.” However, I see a difference between saying (1) that our presence in the universe confirms, tautologically, that the universe is suitable for human beings (otherwise, as you correctly conclude, “we wouldn’t be here to admire it”), and saying (2) that the universe was made for us.

Assertion 1 is passive and self-evident, where human beings are just a banal happenstance — an insignificance, even — amidst the many finely tuned physical constants associated with the universe’s evolution and human beings’ relatively sudden appearance in it 13.8 billion years later. In this instance, the physical constants are mere coincidences in their allowing for the eventual presence of human observers to ponder the great cosmic theater.

Assertion 2, on the other hand, is active, hinting at agency of some kind — “of some kind” being a key qualifier. That agency might, classically, have a basis in theology: creation (design) by a god, suggesting that human beings might — though even then, not necessarily! — have a planned special purpose (are exceptional). Or agency (somewhat more loosely and unconventionally defined) might, as others conclude, have a basis in the universe’s self, so to speak, where nothingness is impossible and the singularity of the Big Bang is not a beginning but a stage in the eternal continuation of “something” dominating over “nothing.”

In these contexts, I suggest that “Was the universe made for us?” is a fair question to pose. And does, to piggyback on your point, “make me wonder about the unique circumstances that created us.”

Tessa den Uyl said...

Dear Keith,

Is Heidegger's trouble not that all subjects are human subjects?

Keith said...

My apologies, Tessa, if I miss the mark in attempting to answer your question; there’s a good chance I have misconstrued your point. That said, perhaps one could argue that Heidegger’s ‘Dasein’, its being focused on human experience, by extension relates in some direct way to use of the word ‘anthropic’ in Carter’s original expression ‘anthropic principle’. That is, the Greek etymology of ‘anthropic’ points to this unambiguous definition of the word: ‘relating to human beings’. That’s the intent of the word, of course, in the phrase ‘anthropic principle’ — and, maybe by extension (my guess!), it’s what you refer to by ‘not that all subjects are human subjects’. So, to be sure, the innumerable physical parameters associated with the ‘anthropic principle’ — constants at the level of the universe, others at the level of the galaxy, others at the level of the solar system, and still others at the level of Earth (the last per Martin’s point) — allow for the existence of sophisticated, conscious, intelligent homo sapiens cavorting around at this point in time in the universe's evolution. Perhaps one might rightly object that the anthropic principle is therefore disconcertingly biased: that is, overly human-centric — giving short shrift to other (even non-carbon-based) intelligent life possibly populating habitable exoplanets around the cosmos. But that’s correctible, I would argue, by widening the lens with which one discusses the concepts behind the anthropic principle.

Tessa den Uyl said...

Dear keith,
All answers could be the 'right'-, like the 'wrong' ones. Thinking 'a bit less human', I imagine that the universe doesn't question right or wrongs, time and evolution.
The human subject in the matter, regards the idea of the who. And the who is who? And this question about -who- has to confront, contradict itself towards something not human. But then what is the privilege of the who? What is the subject? What, is the responsibility of the subject?
Then, the word anthropic, I find a difficult term, and ambiguous. If language has structured our experiences still we do not know reality in itself.


Keith said...

A fascinating point you make, Tessa: “I imagine that the universe doesn't question right or wrong, time and evolution.” Or does it? To ‘question’ something, as you phrase it, would require a universe that minimally has consciousness — and probably much else, besides. At the risk of reductionism, I suspect such a notion of a universe ‘questioning’ — that is, ‘thinking about’ or concerning itself with — matters like right and wrong or time and evolution hinges on how literally one were to define and endorse that ages-old notion of panpsychism. You’ve pointed to a big subject, Tessa — an essay unto itself.

Thomas Scarborough said...

I have long admired Copernicus' magnum opus, of which I have a copy in English. Not only was he trying to prove something, but prove it to an unreceptive audience.

Someone said that, to explain a single grain of sand, one would need to create the entire universe. The fine-tuning so-called is 'unbelievable', and this applies at macroscopic and microscopic levels -- even the sub-atomic.

Is not a danger of the anthropic principle the idea of directional evolution, as we saw, for example, in communism? And in theology today, for instance neo-liberalism.

Keith said...

Thanks, Thomas. Briefly to a couple of your points:

Agreed: “Not only was [Copernicus] trying to prove something, but prove it to an unreceptive audience.” And, I might add, all the more riskily and courageously given unsettling images undoubtedly dancing in Copernicus’s head of possibly burning at the stake. It brings to mind the decidedly hoary expression that’s way overused among pundits and the news media these days: ‘Speaking truth to power’.

Agreed: “The fine-tuning is ‘unbelievable’, and this applies at macroscopic and microscopic levels – even the sub-atomic.” As to the latter, quantum theory is a case in point. But your comment also reminded me of an (unattributed) quote circulating and that someone shared with me yesterday: “Humans studied mathematical patterns for centuries and eventually invented programming languages and scientific technology, only to discover that DNA is chemical data that, when executed, creates life. DNA is the program that became aware of itself.” Germane, one might argue – especially the closing sentence of the quote! -- to the ‘anthropic principle’ and its correlation to evolution.

Martin Cohen said...

Tessa says "who is who?" Is this the key issue here - the mystery of cosnsciousness - the mystery some subatomic physicists ahve seen as linking the inner human universe and the physical outer one?

Keith said...

"Is this the key issue here -- the mystery of consciousness -- the mystery some subatomic physicists have seen as linking the inner human universe and the physical outer one?" Yes, Martin, the possible explanatory link between human consciousness and quantum theory is well worth exploring, and may prove lucrative by way of (at least partial) answers to do with what consciousness is. As one might expect, it's a controversial topic, with proponents and opponents speaking out loudly -- especially when one reads the provocative hypotheses of people like Penrose and Hameroff. There are many, many features to this larger subject, of course, such as the role observation (including measurement) has on aspects of reality, including wave-function collapse and the many-worlds interpretation. The latter points to the ostensible link between the 'inner human universe and the physical outer one'. 'Quantum consciousness' is an intriguing area of research -- but one where neuroscience, apart form quantum aspects, also needs to heavily weigh in.

Keith said...

Perhaps also relevant, Martin, to your topic of a possible nexus between 'consciousness' and 'subatomic physics', here's what was said in an earlier Pi post (along with mention of the 'anthropic principle'): "As [the quantum physicist and cosmologist John] Wheeler postulates, in our looking rearward to the universe’s beginnings [the ultimate macro-sized object], might our observations result in selecting one out of alternative possible cosmic quantum histories, back to the Big Bang almost fourteen billion years ago? And, in line with the ‘anthropic principle’, might that quantum history account for the many finely tuned features of the universe essential for its and our existence — resulting in an objective macro-reality, the same for everyone, throughout the universe?" Wheeler is just one among others to discuss such nexuses.

Thomas Scarborough said...

Perhaps we have rejected too soon the idea that there must be a separation between me and my world. The question is, what is that separation? Descartes doesn't find much favour today, yet what if his dualism was essentially correct? That is to say, what if it is not mind and body, but some other kind of separation, including physical? (Off topic I am).

Keith said...

Your question, Thomas, is certainly deeper philosophically than my brief answer. That said, apart from agreeing to momentarily shunt poor Descartes aside, I struggle with any dualistic notion that separates mind from matter— or, more to your point perhaps, that separates matter from matter. The latter is what, I believe, your reference to ‘physical separation’ actually encapsulates. It’s of course a big topic, but the reason for my skepticism regarding a physical ‘separation between me and my world’, as you put it, stems from looking at the source of what makes human bodies possible. We’re all familiar, in particular, with the science that human life — our bodies, including of course our brains — wouldn’t have been possible without the occurrence of supernovas. That is, the clouds of detritus (assorted elements) that supernovas have routinely been spewing out in clouds throughout the universe for many billions of years. Indeed, our very DNA — and that of other species, far and wide — was fed by the distributed remnants of exploding stars. It calls into question the physical ‘separation between me and my world’. From one angle — physical origins — our debt to supernovas may strike one as an everyday, even banal, part of reality, which perhaps shouldn’t have surprised us. A sweeping up and combining of elements, if you will. From another angle — what our debt to supernovas’ detritus might say about our place in the universe — is, perhaps, far from banal (philosophically or otherwise). At the very least, these concepts about our cosmic-based indebtedness and heritage suggest that a physical ‘separation between me and my world’ might not be possible.

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