= 27d567bc2d48d9f40e9ccc20ea370b15)
Can somebody explain to me why people generally assume that the great filter has a single cause? My gut says it's most likely a dozen one-in-a-million chances that all have to turn out just right for intelligent life to colonize the universe. So the total chance would be 1/1000000^12. Yet everyone talks of a single 'great filter' and I don't get why.
I'd liken it to a chemical reaction. Many of them are multistep, and as a general statement chemical processes take place over an extremely wide range of orders of magnitude of rate (ranging from less than a billionth of a second to years). So, in an overall reaction, there are usually several steps, and the slowest one is usually orders of magnitude slower than any of the others, and that one's called the rate determining step, for obvious reasons: it's so much slower than the others that speeding up or slow down the others even by a couple of orders of magnitude is negligible to the overall rate of reaction. it's pretty rare that more than one of them happen to be at nearly the same rate, since the range of orders of magnitude is so large.
I think that the evolution of intelligence is a stochastic process that's pretty similar to molecular kinetics in a lot of ways, particularly that all of the above applies to it as well, thus, it's more likely that there's one rate determining step, one Great Filter, for the same reasons.
However (and I made another post about this here too), I do think that the filters are interdependent (there are multiple pathways and it's not a linear process, but progress along a multidimensional surface.) that's not really all that different than molecular kinetics either though.
In response to
The Octopus, the Dolphin and Us: a Great Filter tale
I don't think filters have to be sequential - some could be alternatives to each other, and they might interact. Consider the following.
Each supernova sterilizes everything for several lightyears around them. This galaxy has three supernovas per century, and it used to have more. Earth has gone unsterilized for 3.6 billion years, i.e. each of the last (very roughly) 100 million supernovas was far enough away to not kill it.
That's easy to do for a planet somewhere on the outer rim, but the ones out there seem to lack heavy elements. If single-celled, mullti-celled, even intelligent life was easy given a couple billion years of evolution, you still couldn't go to space on a periodic table that didn't contain any metals.
So planets in areas with lots of supernova activity (i.e. high density of stars) could simply never have enough time between sterilizations to achieve spacefaring civilization, while planets in areas with low density of stars/supernovas haven't accumulated enough heavy elements to build industry and spaceships. Neither effect prohibits everything, but together they're a great filter.
There could be other combinations of prohibitive factors, where passing one makes passing the other more difficult. Maybe you need to be a carnivore in order to evolve theory of mind, but you also need to be a herbivore in order to evolve agriculture and exponential food surplus. Or maybe you need tectonic plates to avoid stratification of elements, but you also need a very stable orbit around your star, and those two conditions usually rule our each other. I don't know. It just seems that a practically linear model of sequential filters, where filters basically don't interact with each other, is entirely too simplistic to merit confidence.
In a few years, we'll have a much clearer picture of the chemical makeup of the closest few hundred exoplanets, and that'll cut down the number of possible explanations of Fermi's Paradox to a maybe sort of manageable size. Until then, this discussion is unlikely to lead anywhere.
I don't agree that metals and heavy elements are necessary for industry and spaceships: you can do quite a lot with light elements, particularly carbon (for example plastics, carbon fiber, etc.). Also, biology makes all of its structure through lighter elements.
That being said, I think you're very much on the money with the general idea: I also thought something similar while reading the artifcle (that the filters are likely multivariate and interdependent), but not in as well thought out a way.
In response to
An Alien God
So basically the bottom line I'm getting from this a kind of variant of Occam's Razor: Evolution is unlikely to produce solutions that include complexity or considerations it doesn't need.
Or more specifically, and with an example, there are probably a lot more ways to get to taste buds that give good results in environments and contexts the organism is likely to encounter than ways to get to taste buds that give good results in both environments and contexts that the organism is likely and unlikely to encounter.
In response to
Lonely Dissent
Yeah, I've definitely had to learn the hard way to tone it down with respect to having ideas and interests that run completely orthogonal to familiarity with peers/society.
Perhaps what annoys me even more is when I like something that coincidentally has associated with it one of those Outside The Box groups, when I don't want to be associated with that group, or more accurately, don't want to have to hear the canned response for it, whatever it may be.
For example, I like heavy metal and anime, but have no desire to be a part of those counter-cultural groups. Unfortunately, it's pretty hard for me to talk about either of those things without people -- both inside and outside those ciricles -- from assigning me to that bin. It's not harmless categorization either: being considered to fit in those bins has pretty strong social baggage attached to it.
View more: Prev
= b715d02e85f7b3b4ae65ca3d3e450868)
Subscribe to RSS Feed
= f037147d6e6c911a85753b9abdedda8d){kind=logo}
Interesting. However, I still don't see why the filter would work similarly to a chemical reaction. Unless it's a general law of statistics that any event is always far more likely to have a single primary cause, it seems like a strange assumption since they are such dissimilar things.
Sorry for the delayed response; I don't come on here particularly often.
The assumptions I'm making are that evolution is a stochastic process in which elements are in fluxional states and there ere is some measure of 'difficulty' in transitioning from one state to another, an energetic or entropic barrier of sorts, that to go from A to B (for example, from an organism with asexual reproduction to an organism with sexual reproduction) some confluence of factors must occur, and that occurrence has a certain likelihood that's dependent on the conditions of the whole system (ecosystem). I think that this combined with the large numbers of physical elements interacting (organsims) is enough to say that evolution is governed by something pretty similar to statistical thermodynamics.
So, from the Arrhenius equation, k = Ae^{{-E_a}/{RT}}
where k is the rate of reaction, A is the order of reaction (number of components that must come together), E_a is the activation energy, or energy barrier, and RT is the gas constant multiplied by temperature.
The equation is mostly applied to chemistry, but it also has found uses in other sectors, like predicting the geographic progression of the blooming of Sakura trees (http://en.wikipedia.org/wiki/Cherry_blossom_front). It really applies to any system that has certain kinetic properties.
So ignoring all the chemistry specific factors (like temperature), the relation in its most general form becomes
k = Ae^-BE
This says essentially that the rate is proportional to a negative exponential of the barrier to the transformation, and small changes in the value of the barrier correspond to large changes in the value of the rate. Thus, it's unlikely that two rates are similar. I don't see why two unrelated things would be likely to have a similar barrier, and given this, they're even less likely to have a similar rate.