Cosmology

What a Life Is Built From

biology
heredity
species
cross-biosphere
survey-corps
doctrine
non-humanoid
medical
chemistry

A description of a body that begins with its molecules has begun at the wrong end.

What a life is built from is the question every Survey Corps filing answers last, and the Academy teaches it that way on purpose. DNA is one solution, found once, on one world, and the cell is the same kind of fact: a local answer to a general problem, so familiar that it reads as the problem itself. This entry is the general problem stated on its own — the four things any life does — followed by what the record has actually found doing each of them, so that a medic, a quartermaster or a first-contact specialist can recognise a life that shares nothing with Earth's and still know what to look for.

Four Things Every Life Does

The Cascade settles that biological life is a formtype: self-maintaining, self-replicating, energy-processing structure is a permitted shape, standing prior to any world. The survey reads that permission as four working requirements, and the four are the whole of what it will assert about a living thing before it has looked closely.

A boundary. Something is inside and the world is outside, and the difference is kept up by work. Where the boundary fails, the life ends.
A metabolism. Energy is taken in one form and spent in another, and the spending is what keeps the boundary and everything behind it.
A record that copies, with error. Somewhere the life keeps an account of how to build itself; the account is copied when the life is; and the copying is imperfect, which is the only reason there is a history for a lineage to have.
Organisation. Parts differ, cooperate and are replaced, and the whole outlasts any of them.

Everything else — the molecule the record is written in, whether the parts are cells, what the solvent is, what the body is held up by — is implementation, and the record has now met enough implementations to state the rule the other way round: the four requirements recur on every surveyed world; not one of the solutions does.

The Record Without the Molecule

The third requirement is the one Earth biology finds hardest to imagine done otherwise, because Earth has exactly one way of doing it and calls the way heredity. The survey record holds several, and the page groups them by how far from the familiar they stand.

Other polymers. The nearest cases keep the strategy — a long molecule whose order is the record — and change everything about the molecule. Different backbones, different alphabets of more or fewer letters than four, the opposite handedness, a chain that stores and works at once instead of dividing the jobs. Prismere's silicate-carbon biosphere writes its record in a chemistry that builds glass into tissue, and Sardain's runs in a solvent that is not water and at temperatures where water is a mineral: a heredity that works there would not survive a Solar System laboratory bench, and the reverse is equally true. The survey calls these genes in the filing, on the standing principle that the original is the document and the conversion is the courtesy, and a medic who reads the word and reaches for nucleic chemistry has made the error the whole vocabulary exists to prevent.

No polymer at all. Further out are worlds where the record is not a sequence. On some it is a composition — a mixture whose proportions are the account, passed on by division and kept faithful by the chemistry of the mixture itself rather than by a copying machine. On at least one the earliest records were kept on mineral surfaces, and the life there has never entirely left them: what is inherited is partly a body and partly a place. The survey files these as heredities because they meet the requirement — an account, copied, with error — and it records that the word gene has nothing to attach to.

A partner instead of a code. Verdance is the record's household case, and the taxonomy file states it plainly: kinbed bonding passes a partner rather than a gene, and it is not a custom laid over a normal heredity, it may simply be what heredity is there. The general form recurs elsewhere: what a parent gives a child is a living companion whose own lineage carries the account the host's does not, and the two records — host and partner — are inherited together, on different terms.

And the limit case, which the survey states carefully. The requirement is an account of how to build a life, copied with error. On Fliade a people keeps its whole record by speaking it, and the survey's word inheritance has been used, in filings, for what passes by telling as readily as for what passes by body. The record files both, and marks the line between them as a translation too: where a life's continuity runs through what it is told, the Corps does not get to decide that only the chemistry counts.

The Body Without the Cell

The fourth requirement is the one the direction multicellular names, and the word is a translation like every other. A cell is a bounded unit; a multicellular body is many of them, cooperating, differentiating, and replaced. What the requirement asks for is the cooperation, the differentiation and the replacement. The units are Earth's way of getting them.

The record has found the same requirement met in at least three other shapes, and the taxonomy file's frames sit across all of them without caring which.

Modular bodies, built of many bounded units — Earth's cell, and units on other worlds at other scales, from far smaller to visible to the eye, none of them cells in anything but function.
Continuous bodies, with no units at all: one unbroken living volume in which regions differentiate, specialise and are renewed without there ever being a boundary between them. The survey's first continuous body was filed as a single cell for eleven years, which is the kind of mistake the word cell makes on its own.
Federated bodies, which are populations: many lives that are also one, cooperating closely enough that the whole meets every requirement on this page and the parts meet most of them. Where such a body is also a person, the record counts persons otherwise and says so.

Organic generalises the same way. Every biosphere the survey has examined closely is built on carbon, and the survey has an argument from chemistry for why that should be common; it declines to promote the observation to a law, marks the absence, and would file a life on another element under the four requirements without hesitation. Every word in the phrase multicellular organic biological life is a translation except the last.

What the Survey Does With This

The practical content is the same as the taxonomy file's and the page states it to be exhaustive rather than novel. A medic treats the requirement, not the molecule: a boundary that is failing, a metabolism that is starved, a record that is being miscopied, an organisation that has lost a part it cannot replace — each is recognisable in a life whose chemistry the medic has never seen, and each has a treatment logic that does not depend on it. A life-support officer provisions for the metabolism as filed. A first-contact specialist looks for the four requirements and the finding about the mind, never for a body plan, and never for a chemistry.

And nobody argues from substrate to standing. That a people's record is a composition, or a partner, or a telling, says nothing about the people — the Ilveth, running cold in a solvent that is not water, are in the Corps. The four requirements are what a life does. What it is made of is a fact about its world, and the record files it as one.