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[Tristan Alkai]

Wow.  Lots more activity than there had been the last few days. 

First to GavJ, about quotes.  Please include links with them.  It's politeness to other people reading what you wrote.  My one exception to this advice was because I didn't know how, and that one has since been fixed. 

When drafting a reply, I use the right click "open link in new tab" option, leaving direct access to the rest of the thread.  Each post I want to quote from also gets opened in a new tab, and I copy-paste from it.  Each time, I also copy the "quote author" tag that gets auto-inserted at the top. 

Aether

Read the thread first!  Nearly all of your comments about Aether were already made by either me or NW_Kohaku.  I referrred to your "Aether" with the phrase "xenosynthesis energy," and mentioned modifying the "Apply Creature Variation" tag for effect similar to the mutation system you describe.  A lot of the remainder about Aether I disagree with.  I will give more details once I am no longer in the middle of a debate with GavJ.

I don't think we really need to worry about thermodynamics or energy sources so much as what would make a good story.

I WAS working on a presentation about the ecology of magical plants, focusing on the magic-producing ones, and the various ways their ecological niche could affect the magic-consuming (xenosynthetic) ones.  Then GavJ derailed me.

Edit:

Well, if we're going to insist on the logic behind underground energy sources... has anyone given any consideration to the 'eerie glowing pits' in the underworld?  What is causing them to glow? (. . .)  I'd say that of all the energy sources that could be sustaining underground life, that seems like the most plausible.

You have a point, but I see the glowing pits as one source (sphere) of magic energy among many.  It works through the standard magic field system.  Surface plants give a lot more variety, and synchronize better with a stated goal by Toady One to have sphere-based surroundings. 

Maybe magic is seasonal.  Sweet Pods only grow in the Spring and Summer because that's the only time when the whatever sphere is in its waxing period.

I can easily concoct a way for mana from surface plants to be seasonal.  Eerie glowing pits?  Not so much. 
/Edit

If you have a perpetual motion machine, you've just utterly changed everything in a society, in a way more fundamental than electricity. In its most mundane form, cars never need more gas. The entire energy segment of the economy gets transformed into something that's weirder than we can possibly imagine.

In other words, a break to Thermodynamics will not result in a comprehensible world.  It is too fundamental; too much else is based on it. 

I want to keep it (Thermodynamics) fully intact and unmodified at all costs.

On that note, I have not yet located a comment from GavJ that addresses this issue.  I am using xenosynthesis and the rest specifically to avoid a break to thermodynamics, and this seems to have been ignored. 

Perhaps more concretely, we have 3 options here being discussed:

1) ((magic cave creatures, consistent with:) (cave plants based on that same magic)) (other plants and non magical stuff)
2) (magic cave creatures) ((non magical cave plants consistent with:) (other plants and non magical stuff))
3) ((non magic cave creatures, consistent with:) (non magic cave plants, also consistent with:) (non magic other plants and stuff))

We agreed that using option 3 would alienate me (and, by implication, a faction of the player base with similar inclinations), then you said 1 and 2 are equally logical.  I appealed to thermodynamics to justify favoring option 1. 

So is this pile of skeletons over yet?

Not even close.  Undead and the breaks in logic they involve have become a major part of my argument.

As far as my biologic knowledge goes chemosyntesis are not the best source of energy for any kind of bigger creatures.

1) Why not? If you simply had more of them than on earth.

Have you looked up primary production for chemosynthesis?  (I tried and failed.)  One of my starting assumptions in that presentation on magical plants was that the cavern primary production was at least 10% of the surface, probably more like 100%.  I don't think chemosynthesis is capable of that level of ecological productivity, even with the boosts you describe.

My complaint about thermosynthesis is essentially the same as what I understand of your complaint about xenosynthesis.  I see it as unnecessary and creating more problems than it solves.  I followed your link about it, which indicated the process to be purely theoretical.  With that established, I don't see its advantages over xeno. 

The oxygen is must-have and deep in caverns the air isn't the most clean thing.

Earth caves, the air isn't great.
DF caves, full of plants, the air could be wonderful. Plants recycle out breathable oxygen, remember. A sufficiently large, plant-filled cave is not particularly different than the aboveground atmosphere and ecosystem.

How, exactly?  Xenosynthesis is explicitly stated to be essentially "photosynthesis, except using magic," so it will work this way.  Chemosynthesis won't work this way.  Thermosynthesis may or may not produce oxygen, depending.  Precedent: purple sulfur bacteria that use light but don't produce oxygen. 

Can you give me a list [of miracles]?  It would make reducing the number a lot easier.

 
1) Basic geology - nonsensically thin world that doesn't make any sense with our universe's geological workings, etc. (This is the miracle that already exists and that mainly allows for more chemosynthesis than on Earth, and thermal gradients, and also allows for the size of caverns and their water flow, etc.).
1.5) Slade and SMR may or may not be included with #1 (for instance SMR eats infinite amounts of things falling onto it)
2) Some animals move without any observable cause - undead, bronze collosus, etc.
3) Many organisms are immortal as in don't die of old age. FB's and goblins for instance. As well as presumably trees and things if you don't cut them down.
4) Everything about the circus
4.5) Adamantine, sort of maybe. Also might be grouped with #4.
5) Plants grow without sunlight or any other observable means of energy.
6) Ways of permanently destroying matter - Atom smashers and obsidian casting and stuff burning in magma and leaving no trace, etc. The burning is maybe fine "abstract gas is just not modeled" but not the first two.
7) TARDIS-tiles. Time/space work differently in DF. 800 dragons in 3x3x8 feet areas, yet traversing the space takes a fixed time, etc.
I may be missing others.

Okay, here we go. 
1. Dwarf Fortress has a severe case of units not to scale.  A dwarf takes up one tile.  A turkey takes up one tile.  A cavy takes up one tile.  An alligator takes up one tile.  A giant sperm whale takes up one tile.  Thin planetary crust is essentially the same issue: the size of tiles is extremely vague, and available information seems contradictory. 
2. I addressed this earlier as "Magic fields miracle 4." 

As I am describing it, "Magic fields" involve four distinct "miracles."  These combine into a single mostly coherent system. 

1. The magic field itself, which serves as both wireless power transmission and energy storage.  It probably represents a new field within physics.
2. An energy receiver, in the form of a biochemical pathway (xenosynthesis).  In other words, a tweak within biochemistry. 
3. An energy producer and transmitter, in the form of another biochemical pathway (call it "alchemical plants" for now).  In other words, another tweak within biochemistry, closely related to the previous one. 
4. A different receiver, exploited by non-biological "creatures" such as undead, amethyst men, and blizzard men.  I'm not sure where this one lands.

3. This is called negligible senescence.  It is rare in real life, but not rare enough that I consider similar creatures in Dwarf Fortress to be a problem. 
4. I can probably fold clowns into miracle 4.  Other aspects of the circus may end up as a fifth miracle: an inorganic mana transmitter (joined to miracle 3 the same way 4 is joined to 2). 
5. This was magic fields miracle 2. 
6. I'll listen if you think I'm wrong, but I understood stuff disappearing during obsidian casting to be an implication that it got destroyed by the magma.  I don't know what to say about atom smashers. 
7. As described above, this and 1 are different effects of the same issue. 

[GavJ]

How, exactly?  Xenosynthesis is explicitly stated to be essentially "photosynthesis, except using magic," so it will work this way.  Chemosynthesis won't work this way.  Thermosynthesis may or may not produce oxygen, depending.  Precedent: purple sulfur bacteria that use light but don't produce oxygen. 

I did forget about oxygen being a photosynthesis thing, but this is still not a problem.

Because chemosynthesis can certainly work that way, in fact it might even have to depending on the environment. Chemotrophs don't JUST do the basic hydrogen sulfide thing. That's just the main sugar reaction. They have whole suites of reactions to make all the other crap that need. Not only can some of these potentially create oxygen, but they sometimes must do this, because oxygen is needed to burn their own sugars later, and they tend to be in various extreme places with little oxygen. And when they do make their own, it is very unlikely that they just happen to make precisely as much oxygen as they need for themselves.

Just like plants, an excess is more likely (and probably exists right now, I just don't have any citations). Certainly this happened in antiquity, at least, in order to have created the oxygen excess that originally converted our atmosphere and saturated all our iron, etc. The first cells obviously weren't plants.

One of my starting assumptions in that presentation on magical plants was that the cavern primary production was at least 10% of the surface, probably more like 100%.  I don't think chemosynthesis is capable of that level of ecological productivity, even with the boosts you describe.

Just from videos I've seen, the area right around a thermal vent is quite populated, actually. If they blanketed a whole area, there could probably easily be ~50% the bio density as in a surface ecosystem. Just guessing, but easily more than 10%.

[miracles]

Not worth bickering about most of these that are tangential, for the most part I agree with your comments.  However:

1) To the extent that you're really conceiving of your plan as 4 more miracles, that's not a very palatable system... and not covering all your weird organism bases with even the same system undermines the reason for trying to group them together in the first place.  If you think magic is the best (outside of the option of just cutting down on magic animals) explanation, then fine. Like I said I see the remaining options as mostly neutral. But at the very least try to come up with a miracle that covers all of it in one swoop. Couldn't you just say something like a 4th spatial dimension or whatever? Immediately next to everything, but only certain things are connected to it, and gathering energy from there, to dispense with all the weird energy internet transmitters system thing? Or I don't know, it needs refinement if going there.

2) The issues with the geology go way beyond scale. First of all, the scale is totally nonlinear, which makes it not really "Scale" anymore, but warping, which implies a true miracle, not a notation game design thing only. But also, stuff like SMR just absorbing infinite mass, plate tectonics not making any sense (plates wouldn't even float in that little relative magma!) or with slade unbreakably beneath, a whole bunch of things. But none of that is gonna change, so it is what it is. Just sayin'.

[Tristan Alkai]

Not only can some of these potentially create oxygen, but they sometimes must do this, because oxygen is needed to burn their own sugars later.

No, it isn't.  It's called fermentation.  Oxygen is favored when available because it produces much MORE energy per sugar molecule, but some energy is available with sugar and no oxygen.  Even animal cells (including humans) use anaerobic glycolysis, which produces energy without oxygen.  The "burn the sugars" with oxygen works on the products of glycolysis.

Also, have you heard of chlorine?  Molecular oxygen presents ALL the same hazards, and is, by some measures, WORSE.  Aerobic cells require extensive adaptations to cope with (not to mention use) oxygen, and they are far from perfect.  Relatedly, the photosynthetic "water splitting" reaction requires a large energy investment.  Photosynthesis uses light for this investment, but I don't think chemosynthesis can pull it off.  Conclusion: chemosynthetic "plants" will not produce molecular oxygen, and thermosynthetic ones are highly unlikely, especially when hydrogen sulfide is available.  It's less hazardous and easier to work with.

Certainly this happened in antiquity, at least, in order to have created the oxygen excess that originally converted our atmosphere and saturated all our iron, etc. The first cells obviously weren't plants.

The leading suspects for the oxygen catastrophe are cyanobacteria, which DO carry out photosynthesis.  The claim has also been made that the chloroplasts used by familiar plants are descended from cyanobacteria. 

To the extent that you're really conceiving of your plan as 4 more miracles, that's not a very palatable system...

At the very least try to come up with a miracle that covers all of it in one swoop.

Let me re-phrase: I see the magic field ("mana energy") as one miracle, and the rest as consequences of that miracle.  With the modification of physics to permit mana, the ability to interact with it is implied.  Interactions are performed by both organic (biochemical) and certain inorganic systems (undead, bronze colossus, amethyst men, and so on).  Possible interactions include all of the following:
1. Draw mana from the magic field and use it for other purposes. 
2. Convert other forms of energy into "mana."  I use the phrase "alchemical plants" for those that use sunlight, as a reference to a different thread.  This one, I think?  (Edit: There's some useful stuff behind the Xenosynthesis spoiler in the first post, and more over here on a different thread.)
3. Directly store mana internally, and move mana from that storage to other parts of the body.
> The miracle is this whole interdependent system.  Without 1, 2 is meaningless.  Without 2, 1 will rapidly exhaust the supply and become meaningless (if a supply is even present in the first place).  3 is something else on the side to simplify certain implementation details, and permit other things I wanted to do. 

Couldn't you just say something like a 4th spatial dimension or whatever?

That has a few other consequences I don't want to deal with, starting with the ability of pressurized fluids to flow in that direction. 

To dispense with all the weird energy internet transmitters system thing?

With mana present, I don't see xenosynthesis as any more weird than photosynthesis.  Think about it.  Rocks don't really change much when light shines on them (they heat up, but that's about it).  Same goes for water.  I could go on.  Plants change a lot, and in a completely different way, when light shines on them.  Kinda weird when you stop to think about it. 

The issues with the geology go way beyond scale. First of all, the scale is totally nonlinear.

Let me try this again.

The size of tiles is extremely vague, and available information seems contradictory.

Non-linear is a way of being contradictory.

[GavJ]

Okay I understand why you're only calling it one miracle, that makes sense.

But main response to that now that I understand better: If you have to postulate the evolution of a theoretical chemical system for converting mana into ATP or whatever, then you're no better off than the theoretical thermosynthesis being evolved. And in fact you're worse off overall, because you have equal obligations for theoretical evolution PLUS a big crazy mana field.

Minor responses:
1) You don't need #2 of your 4 steps. The mana field could simply be large enough to sustain draws on it for billions of years or whatever. That would be no different than sunlight, really. Mana here is just another type of energy from the Big Bang or what have you, and sure it will get exhausted, but doesn't have to imply "rapidly.

2) #3 is not necessary, either. You only need to have a single special site/molecule/whatever that converts mana into ATP or some normal chemical carrier OR that just uses its energy instantaneously and then keeps the juicy products, and you're fine. This makes it way simpler than having to store mana or move it. Think about sunlight -- plants don't store or transport sunlight. Its fantasy replacement need be no different.

But you say it does other things you want to do -- which things? Are they really worth the big jump in extra complexity and lower plausibility of being able to store and move weird extradimensional energy itself?

With those two gone, it seems much more elegant to me, and probably fine as is.




Just since I thought of them though, a couple other plant solutions?

1) Since in DF, temperature doesn't move beyond 1 tile from a source, and since even then, it's only like 100 degrees F or something right next to magma, plants or bacteria could possibly grow immediately over the magma sea using magma light for photosynthesis (like on the ceiling of the magma sea), as a primary producer, and then the grass and stuff you see in the caverns just has "roots" (in quotes because they're for food nutrients more than water) that go down there and continuously gobble up the photosynthetic bacteria. This also relies on an EXISTING miracle of weird thermodynamics in the game that are unlikely to change.

2) A lot weirder than #1, but dwarves don't need torches underground, right? Nor is darkness ever really mentioned I don't think, etc. Maybe light in this universe is just A) much more abundant and B) has more penetration by far. I.e. all matter is translucent to light, and a mile of rock doesn't really make it much darker, because you sitll have 99.8% of the surface light or what have you. This isn't quite a new miracle, because it explains a bunch of other things that were already weird. And it's not quite as much of miracle at all, because it is more closelypossibly to known physics than whole extra fields of magical energy or whatever. Explains also why all rocks are exactly the same temperature underground (they all have nearly uniform radiant heat exposure!), and the lack of need for lighting. Also granite windows. Although on the flip side, it makes it tricky to explain why enemies can't see threats through walls.

3) Still think that chemotrophs + optional thermotrophs are a viable possibility. You mention fermentation like it's a major problem, but couldn't it actually explain why dwarves are so alcohol dependent? They evolved in caverns to take advantage of a naturally abundant byproduct of the chemosynthetic bacteria! We also have not much evidence that dwarves really need oxygen. You can lock one in a sealed room for years with water and food and they'll be fine... Maybe they even ferment by themselves or have abundant fermenting gut fauna or something... Also notice how dwarves are immensely slow at doing everything. It takes like 2 days to walk across the fort sometimes. Perhaps this is due to anaerobic biology not just game design issues like expected? Maybe dwarves even do chemosynthesis themselves, and the only reason they drown in water is being cut off from hydrogen sulfide for too long, or something (they don't die above ground, but they do get sick! Maybe in DF universe, there is a decent amount but just lower concentration of sulfides in the upper atmosphere as well due to the extremely close proximity of magma and volcanism everywhere. Sort of like athletes training at high altitudes, they have to be accustomed).

[GavJ]

Btw:

So magma light would definitely be in the right range

[Tristan Alkai]

The mana field could simply be large enough to sustain draws on it for billions of years or whatever. (. . .) Mana here is just another type of energy from the Big Bang or what have you.

From the "Development Goals" list:

Adventurer Role: Explorer
(. . .)
    Lands and beastiary
        More overland map features and local variations
        Scrap good/evil lands for lands with more variety
        Randomized critters in other categories (vermin, roaming creatures, soil critters, plants, etc.), naming them
        Being able to look at a list of all known creatures you've seen and where

Mana is a way to get "lands with more variety."  Always has been.  Something from the Big Bang would, by definition, be present (and very close to even) throughout the world, which runs against that goal of variety. 

Once that variety is in the game, certain players will want a way to CHANGE the variety of magic present on their embark zone, so it needs to be able to run out.  A mechanism of running out also permits a "the magic goes away" sequence of events, which I and others have mentioned before. 

#3 is not necessary, either. You only need to have a single special site/molecule/whatever that converts mana into ATP or some normal chemical carrier OR that just uses its energy instantaneously and then keeps the juicy products, and you're fine.

One of the ideas I wanted was that necromancers would be able to siege your fortress even if you embarked in an area without the Death mana their undead need.  Undead don't HAVE a biochemistry to store other products with, so they need to use mana directly.  In order to leave their Death mana area, they need an internal storage.  Animating a new undead would also use Death mana, so necromancers need some way of bringing it with them. 

But you say it does other things you want to do -- which things?

Alchemy. 

Fruit (and possibly other plant parts) can contain XE in portable form.  Intelligent creatures which require XE (such as necromancers) can carry appropriate types of fruit with them.  (. . .)  This also has implications for alchemy.

I want alchemy to be available, and I believe internal storage of mana in certain materials is required.  Biological materials were the ones that made most sense to me.

Implications part 2: Magical creatures
1. Creatures that can use XE will have a personal XE pool, separate from that of the region.  They can fill it either by eating a plant that contains XE (the [NO_EAT] token may or may not prevent this), or more directly from the ambient pool.  Death of the creature probably releases its energy into the region pool. 
2. A creature that requires XE to avoid hunger can draw from its personal pool, or that of the surrounding region.  The creature’s personal pool probably has a maximum size, and it can release XE into the environment when this fills up. 

As above, I want plants to be able to store mana internally.  When an herbivore (or other creature) eats such a plant, this mana will end up in its body.  The internal mana storage for creatures is a logical consequence.  After I establish that plants can do it, there is no inherent biochemical reason animals wouldn't be able to do it too.

As I understand it, xenosynthesis is a way of supporting and enforcing Conservation of Energy.  This description has implications for how it should be implemented. 
(. . .)
3. Certain creatures (including, but not limited to, [NO_EAT] ones) will also consume XE.  I see a solution involving most of the same code as the current [GRAZER] token: the creature consumes one point of XE from the region to reduce “hunger” by an amount that varies with the creature.

This implementation has several features:
1. As I have described elsewhere, non-living creatures consume magic energy.  For Conservation of Energy to be respected, this consumption needs to be tracked. 
2. This implementation offers the simplicity of being able to use the existing "hunger" system.  Mana (XE) is a new food type.
3. It permits creatures to leave their home magic biomes, at least temporarily.  This permits the necromancer siege described above. 

Still think that chemotrophs + optional thermotrophs are a viable possibility. You mention fermentation like it's a major problem.

Fermentation is a counter to your claim that chemosynthetic stuff needs oxygen later.  By implication, it also undercuts your claim about them producing breathable cavern air.  Correct me if I'm wrong, but human adventurers don't have breathing issues down there?  And I think we established that ventilation from the surface was not sufficient. 

Also notice how dwarves are immensely slow at doing everything. (. . .) Perhaps this is due to anaerobic biology not just game design issues like expected?

Most anaerobic life-forms are poisoned by oxygen (remember my comment about chlorine?).  Oxygen is strongly favored when available, because each glucose molecule produces 36 ATP with oxygen, and I think 4-6 with fermentation.  If dwarves are faculative anaerobes, this would imply either a vast disparity in speed when dwarves are on the surface, compared to sealed caves, or a vast disparity in food consumption, neither of which we observe.  I believe dwarves are obligate aerobic like humans. 

Your comment about ethanol is also flawed: Ethanol is a product of fermentation, not something that could be fermented further. 

[GavJ]

^

Simple enough. ALL life in DF world is primarily or entirely anaerobic, and the surface atmosphere is only slightly more oxygenated than caves, just enough to make dwarves sick, but not dead, and likewise not humans dead in caves. Both have much less oxygen than Earth though.

They still have photosynthesis as A primary production surface side, but they have simply only happened to evolve some of the less efficient chemicals that provide like, 7-8 ATP instead of 36 or something.

Primary production in surface plants = Lesser amount of chemosynthesis (but still some, since the atmosphere still has much but lesser amounts of sulfides) + supplementary photosynthesis.

Primary production in caves = all chemosynthesis, which is more efficient due to higher sulfide concentrations nearer the source, so they still maintain about as much life down there.



Where does the extra oxygen go? Easy enough -- there's still enough elemental metals around that excess oxygen is still getting absorbed geologically to make oxides. And in fact, there actually ARE many more elemental metals in DF than on Earth!!




Also overall amount of life is way less than on Earth -- only one species of animal wanders by a several acre site per season? Way fewer large animals in this game. Makes total sense for the more meager living from chemosynthesis in DF than on earth.

[Tristan Alkai]

Thermosynthesis was pretty weird, but this is your weirdest yet. 

Simple enough. ALL life in DF world is primarily or entirely anaerobic.

Um, how is this a realism advantage over mana? 

DF has humans.  DF has cows.  DF has elephants.  DF has pine trees.  DF has rats.  DF has bamboo.  There is NO POINT in using those names unless they actually refer to what the reader (player) WILL THINK they refer to. 

Also overall amount of life is way less than on Earth.

I always took this as a limitation of the game engine, that would be corrected later.  I remember reading on the wiki that the game limits animal herd sizes at a fortress to about 50 per species (they don't get pregnant or lay eggs past that point), presumably for FPS and/or RAM reasons.  These are the ONLY logical reasons I can come up with for this behavior.

(Edit) There are arguments of space and food, but those would be a more complex algorithm, not a flat cap. (/Edit)

They still have photosynthesis as A primary production surface side, but they have simply only happened to evolve some of the less efficient chemicals that provide like, 7-8 ATP instead of 36 or something.

I don't think that's how it works.  Admittedly, I'm not a biochemist, but I always understood aerobic respiration to be more productive than fermentation due to the vastly greater energy difference between reactants and products. 

Primary production in surface plants = Lesser amount of chemosynthesis (but still some, since the atmosphere still has much but lesser amounts of sulfides) + supplementary photosynthesis.

I KNOW this is not how it works.  Light (photosynthesis) is strongly favored when available.  "Plants" would have no solid biochemical reason not to use light if possible.  It increases energy gathering, and allows plants that can do it to out-compete those that can't.

(Edit) Also, remember our old friend purple sulfur bacteria?  They carry out photosynthesis, but don't produce oxygen.  They produce sulfur.  (/Edit)

[GavJ]

There is NO POINT in using those names unless they actually refer to what the reader (player) WILL THINK they refer to. 

I agree.

And what most (or possibly literally ALL) players are going to think abotu when they hear "cow" is "an animal shaped like a cow that moos and eats grass and is kinda dumb" NOT "a eukaryotic organism that undergoes cellular oxygen respiration."

Since the hypothetical partially anearobic version of a cow might very well look similar and have similar behaviors, calling such a thing a cow is far less confusing to the normal player and represents a much easier learning curve than having to memorize 80 bazillion new pointless species names like "Zingbats" or whatever.  So there's definitely a practical point to using that name, even if not 100% identical, because the things that people actually think about still do match.

I think that few people, even if they were to be told that this is a largely anaerobic world, would care at all that you still used the word cow to describe cowlike anaerobic organisms.

These are the ONLY logical reasons I can come up with for [limited species numbers]

You mean, except the other logical reason I just gave...? More limited energy source = fewer organisms, fits perfectly.

I always understood aerobic respiration to be more productive...

I am not arguing that. I'm saying that they simply cannot rely on aerobic respiration, because there ISN'T ENOUGH OXYGEN for them to do so. It's only more efficient/better when you have the necessary ingredients. If you don't, then relying on it will kill you, which isn't exactly what I'd call efficient.

Also, it's entirely plausible without postulating any special physics to say "This world just never evolved the most efficient chemical process." Evolution is based on random mutation. It never guarantees anything, and in fact Earth biology is almost certainly NOT optimal either. There is probably some other sunlight based chemical reaction way more efficient than photosynthesis that we just haven't evolved, by random chance and the complexity of that reaction, and whether there are intermediate adaptive steps, etc.

Even evolving what we already did might have been extraordinarily lucky for all we know. Maybe the reason we don't see any aliens out there is because evolving chlorophyll was just SO unlikely that we are 1 in a trillion and all other alien species are still purely running off of things like fermentation!  Totally plausible.

"Plants" would have no solid biochemical reason not to use light if possible

It just hasn't been evolved yet. Period. SImple as that.

You could just as easily argue Neolithic age humans had NO solid reason not to use electricity! It's so much better at everything than stone tools are! And you can way outcompete people if you use electricity!"

Well that's nice, except they just hadn't invented it yet... It's not like they had it available, and then rejected it.

Similarly, "plants" in DF may have so far evolved a less efficient version of photosynthesis (one that isn't nearly as universally optimal as ours) and not anything better.

purple bacteria

So?

[expwnent]

There's nothing magic about a fourth spatial dimension. It wouldn't be an infinite source of energy unless there's a free energy device outside the 3-plane the game takes place in, and if that's acceptable then it should be just as acceptable inside the universe. (I don't like either)

After reading a lot I confused myself and I'm having trouble seeing the big picture of what the two of you are saying. Perhaps stating your position as simply as possible would help clarify the most fundamental difference of opinion? Are we just looking at ways to explain cave plants and creatures, or also introduce a reasonable magic system at the same time? (or is that the difference?)

[GavJ]

There are two possible goals, we sort of even disagree about the goal:

A) We are trying to explain as many of the weird things in the game as possible, while using the fewest overall number of "miracles" / "significant departures from Earth physics"

B) We are trying to have as few parts of the game as possible depend on miracles.

I sort of prefer (B), but most of the discussion has been about (A) because Tristan just sort of flat out implied he wasn't okay with (B), so for sake of argument...

_______________

So then within  that, you want to come up with the minimal list of weird things that simultaneously explains: cave plants and large creatures, undead zombies, the TARDIS-like dimensions of the world, blah blah blah.

He wants to just explain cave life as based on the same thing that makes zombies function. I want to--if possible--explain cave life using plausible alternative histories but still using Earth-consistent physical laws, in order to reduce the number of things in the game dependent upon magic. Even if we sitl have to suggest some other mechanism for zombies.

(See again, (A) vs. (B) above.)

If you have fully decided that (A) is correct, then I'm fine with a "mana field," as long as it's as streamlined as possible. So within Tristan's starting assumptions, I agree with that minus one or two of its complexities.  Not just within Tristan's starting assumptions, I still prefer something like the anaerobic creatures etc.

[Tristan Alkai]

Fairly good summary of the debate.

There are two possible goals, we sort of even disagree about the goal:

A) We are trying to explain as many of the weird things in the game as possible, while using the fewest overall number of "miracles" / "significant departures from Earth physics"

B) We are trying to have as few parts of the game as possible depend on miracles.

GavJ is correct.  I consider magic an inherent part of the game, so I do disagree with goal B.  GavJ has a distaste for magic that I neither share nor understand.

I am not concerned with the number of miracles so much as their magnitude.  That respecting science article I linked to earlier explains what that means and why I care far more eloquently than I can.

Not just within Tristan's starting assumptions, I still prefer something like the anaerobic creatures etc.

You claim that thermosynthesis and a thriving anaerobic biosphere are NOT "significant departures from Earth physics."  I disagree.  Anaerobic can get a dense microbial mat, maybe even something like clams and worms, but not active creatures with large brains like humans and dwarves.

Hydrothermal vent creatures aren't all that active.  A clam doesn't get up and walk around, so it can live happily with not much energy input, but a dwarf going about his daily labors needs more energy than anaerobic metabolism will provide, to say nothing of a fortress of more than 100 plus livestock.

Worse yet, humans and dwarves are both homeotherms.  That takes a HUGE amount of energy, far more than anaerobic metabolism could possibly provide.

Since we're deviating from Earth physics and biochemistry either way, I would rather go all the way and not try to fool myself about it really being plausible.

Since the hypothetical partially anearobic version of a cow might very well look similar and have similar behaviors, calling such a thing a cow is far less confusing to the normal player and represents a much easier learning curve.

The game has dralthas, jabberers, helmet snakes, and so on.  All new names.

Also, your argument about "calling such a thing a cow" does not apply to humans, which are also in the game.

(Edit:)

These are the ONLY logical reasons I can come up with for [limited species numbers]

You mean, except the other logical reason I just gave...? More limited energy source = fewer organisms, fits perfectly.

You misunderstood my complaint.  The issue isn't that the cap is too low; the issue is that the cap is too flat and too hard.  If the issue is food, then that should be reflected in the code. 
Example: Track highest three or so "hunger" numbers and when they happened, remove after 1-3 years.  Bump numbers down the list when current hunger value exceeds them.  Remove lowest one when the list is too full.
Another example: Track highest 5 hunger numbers (without time stamp), bump and remove as above.  Also remove the highest one each year change. 
There would be a chance of pregnancy/egg laying, and this chance and clutch/litter size would both be tilted by that hunger record.  Herd size would be relevant only to the extent that it impacts the hunger record. 
Conclusion: A flat population cap that does not change due to local circumstances can only be motivated by computer hardware constraints. 
(/Edit)

[Tristan Alkai]

Here it is: Like Reality Unless Noted. 

Summary: Fictional worlds, including Dwarf Fortress, are assumed by default to be like Earth except where this assumption is specifically contradicted.  Therefore, words that identify livestock and such are assumed to refer to the same things we are used to.  EXACTLY the same things in ALL respects, including both superficial traits of appearance and behavior, and more esoteric traits like cellular metabolism.

Obviously, I can't stop you from calling a smeerp a rabbit, but I am very firmly of the opinion that it's a bad idea.  In this case, I see no beneficial purpose to doing so.

[GavJ]

Here it is: Like Reality Unless Noted. 

It IS noted otherwise -- in the description or the flavor files or wherever you're proposing this stuff actually matters in the first place.  I.e. the same place you were planning on mentioning mana fields...

Anyway, the other solution I mentioned gets around all these details anyway and I think is stronger:
1) Photosynthetic bacteria and plants evolve from chemosynthetic ones right by the magma sea. Initially this happens near the lip of the handful of underground lava tubes that extend into caves and thus get splashed with water and have magma light.
2) They then evolve long leaflike tendrils that crawl around and seek out more magma light, through cracks and things.
3) This eventually becomes vines that can extend from a place with water down into and across the whole top of the magma sea, surviving heat death due to the miraculous insulating properties of DF space (which already exist). They can be arbitrarily long and connect between magma sea and caverns where water is all over the place. They can also force cracks in rock and open new paths between watery areas and the magma below.
4) These eventually can become tunnel tubes and very large treelike plants. The caverns are richly oxygenated by their photosynthesis. And organic molecules like amino acids are continuously synthesized from CO2 chemically by remaining chemotrophs and specialized plants and things.
5) Animals evolve (likely mostly coming from the surface in small numbers via caves and then adapting) to take avantage of the oxygen rich and food rich environment. As well as other types of plants living off the decaying matter of the primary ones.
6) Life eventually gets about as dense as the surface, since the entire magma sea's ceiling is basically now a dense mat of leaf/tendrils/root/things. And even though it is dimmer than sunlight, it's also on 24 hours a day, making up for that.



MANA SIDE OF DISCUSSION:

Alchemy. [reason why mana needs to be stored itself]

Huh?
Not following you. Alchemy can also just put ingredients together, get everything ready, then somehow open it up to the exposure of the mana field and have the reaction go in real time from there. The equivalent of your final incantation in a classic witche's brew situation (except here it could just be tossing in some manasynthetic algae or whatever). No need for storage or transit.

As above, I want plants to be able to store mana internally.  When an herbivore (or other creature) eats such a plant, this mana will end up in its body.  The internal mana storage for creatures is a logical consequence.  After I establish that plants can do it, there is no inherent biochemical reason animals wouldn't be able to do it too.

Again, think of sunlight. Do animals eat the stored sunlight in plants? No, the plants briefly use sunlight to power a reaction, then the sunlight is gone and they store energy as sugars and fats etc. Animals eat sugars and fats, not sunlight. They don't need to eat the mana either, or store it or transport it, for cave ecosystems based on mana to work. None of the organisms do. Not even the undead, etc. -- they can just be continuously tapped in.

A mechanism of running out also permits a "the magic goes away" sequence of events, which I and others have mentioned before. 

Just divert or block the field. No need for it to run out. Sunlight never runs out. So? You can still have darkness in the world. A volcano can erupt and blot out the sun for months or years... It didn't run out, yet it still went away locally. So can natural or sorcerous events similarly deny access to the mana field even if it is still plentiful beyond the obstruction. This is much less complicated than coming up with some intricate multiple energy source conversions system. Also having to deal with the question of why any organism would WANT to convert energy back into mana, etc. ALSO the lag from all that bookkeeping.

Just having it be nearly infinite like sunlight from some no-need-to-explain natural well is simpler, one-way only, only need the single mechanism for its conversion that evolved or whatever, no energy altruism is implied, etc. It is all around much cleaner. And less laggy since it's just infinite and you don't have to keep track. Not to mention easier to understand, personally.

Something from the Big Bang would, by definition, be present (and very close to even) throughout the world, which runs against that goal of variety.

Everything around us in real life is from the Big Bang.  Is it uniformly, homogenously distributed? No. Why do you assume this of mana when it is not true of the things that actually exist already? In fact, I can't think of anything in nature that IS homogenously distributed. Something that was would feel very unintuitive, not the other way around.

Thus, I don't even think you need to explain this. I think you can just have mana be in bands and swirls and patterns and people will just naturally assume "oh well of course. That's what stuff looks like in nature" without you having to explain or commit yourself to any specific mana-density or mana-gravity or mana-shadows or whatever. They will just swallow it without complaint. And will in fact even expect and assume it!

I've played Magic the Gathering for years, for example, with dozens of people, and participated on their forums, etc... Zero people have ever asked why the mana isn't distributed homogenously, despite it not being explained anywhere and being probably the single most core feature of the game.

[GavJ]

That respecting science article I linked to earlier explains what that means and why I care far more eloquently than I can.

[/quote]
By the way, this link doesn't really support the concept of "lots of physics violations, but not big ones, and that's totally fine." It in fact warns against ALL of the types of issues mentioned previously:

* Avoid too many violations. In fact avoid any violations unless absolutely necessary for the story!
* Avoid big violations especially.
* Avoid the violations having overly far reaching consequences, big or small be the violation itself (which is something we haven't even gotten into with mana, or proposed alternatives really...)