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Comment by whatshisface | Hacker News Reader

This really screams "BS" to me, but I should temper that perception by the fact that I only read the abstract (and so this comment itself would, ironically, qualify for at least one BS flag.)

The most suspicious bit is the claim that organisms can't survive in completely unpredictable environments. That statement is both obviously true or obviously false depending on the variance of the unpredictable random variables... A totally unpredictable temperature between 25 and 26C would not be much of an issue, a totally unpredictable temperature between 0K and 1,000K would be. In fact it would be so much of an issue that its unpredictability wouldn't contribute very much to its difficulty!

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The argument meant in the paper is that organisms encode information about their environment in order to survive. The encoding operation costs energy and generates entropy. Organisms use the encoded information to try to gain (or not lose) energy. Only in environments where organisms can use the information storage cycle to generate net positive energy (and maintain their net negative entropy relative to their environment) can life exist.

In environments which are "too unpredictable", life cannot encode sufficient relevant information for that cycle to be net positive, and therefore life cannot exist. Since life exists, nature is therefore not "too unpredictable".

That's the argument anyways.

For your objection, if we actually lived in a universe where everything was fully unpredictable between 25 and 26 degrees and temperature was the only important variable, then that would be every bit of problematic as between 0 and 1000K. Since life needs energy gradients and quickly destroys existing low entropy states, life always relies on finding temperature boundaries, regardless of how small it is to survive.

That's because continuity is an important part of predictability, right? When temperatures change, they do so continuously in whichever direction. A truly unpredictable environment would see temperatures change effectively instantaneously between points. Even for small differences in temperature, that's anathema for any system. Even simple structures would be unlikely to form as they'd immediately be ripped apart by the sudden change in the state of energy distribution, right?

Hence the ice age..extinction. Organisms only encode for certain levels of environments based on their past history. Some mutations get thrown in, providing select individuals with special doomsday survival genes.

Yeah, I was thinking of making a climate change comparison. Maybe civilization is at a scale that wouldn't allow its own survival should the environment change "instantaneously" (50 years, for a global civ that's endured essentially continuously for 6,000-10,000 years, is instantaneous).

If there are no regularities whatsoever in the environment, how could an organism possibly form and survive?

"No regularities" is one of those things that sounds like it's saying something, but isn't. What does it mean, the laws of physics change every 5 minutes?

It means that the environment at time t is totally unpredictable given the environment at time t-1. If you imagine that the universe at time t is described as a string of random bits, and the universe at time t-1 is also described as a string of random bits, it means that you can't predict any of the bits at t given the bits at t-1. That's what it would mean for nature to be "algorithmically random" in the sense of the paper.

Well the organism IS part of the environment. So it wouldn't be able to encode anything if all it consists of is noise..remember.. we aren't separate from physics...we embody it.

Life is a noise ratchet.

This was also my question.

Obviously there should be some regularity for an organism to form.

But lets assume that the environment for an organism is indistinguishable from the random noise.

Then the only strategy the organism can form is to randomly sample the environment for food.

If there is enough food in the environment then the organism survives, if not then it does not survive.

Therefor it is disproven that an organisms can survive only in predictable environments.

It could be probably displayed that any more complex strategy could be not developed though.

If the environment is noisy at a low-enough level then it won't have enough stability for there to be consistently-metabolizable molecules around at all.

Except that organisms are generally not ergodic systems, so they are subject to gambler’s ruin. Even with “enough” food the probability of non-survival is non-zero and asymptotically increasing over time.

There are pretty compelling reasons to believe that life/physics are strongly tied to computation. See eg the slime molds experiments for some of the more visually impressive cases of that.

The question of how to turn these loose inklings into actionable, falsifiable, reproducible science- rather than Aristotelian armchairing - is a hard one.

When I see those inklings, I uncontrollably see a cellular automata operating on a non grid (or a grid with very small cell size) space. Whether that automata is our or its own implementation is the real question. My hunch is, regardless of the underlying cause, our experiment proves neither.

This is what they are trying to argue: "Information processing in organisms should be understood as the process whereby the organism compares its knowledge about the world with the observable state of the world at a given time; in other words, the process whereby an organism weighs possible future outcomes against its present condition. While the larger the number and the more accurate the processed observables from the environment, the better the predictions and decisions, organisms cannot spend more energy than the total return received from information.".

But that's obviously false.

If the environment is rich in sources of energy, such that expending energy in never really an issue, it makes no difference whether the total return from "processing observables" is more, less or equal to the energy spent doing it.

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