Real Species

[pierre deleporte]

At 21:28 21/04/2004 -0700, Curtis Clark wrote:
>At 09:43 2004-04-20, pierre deleporte wrote:
>>Classic species are classes of individuals. Species themselves are not
>>"individuals". They are not even loosely connected biological systems (the
>>dead individuals don't interact with the living ones, to the difference
>>with spatially restricted populations composed of living, interacting
>>individuals).
>
>Um, my skin cells when I was a fetus interact with my current skin cells in
>a dead vs. living sort of way.

They don't interact presently. You infer that they are connected by descent.

>  I imagine that I have some cells still alive
>from my earliest years, but I think that calling us individuals is specious
><chuckle> in the same sense as calling a species an individual.

The cells in your present body can be observed as cells of the same individual.
The connection between cells in your foetus (what you are no more) and your 
present cells is an inference based on our present scientific theory of 
biological development (= no spontaneous and independent creation of 
different individuals: foetus, baby, adult, but a transforming individual 
through a process of cell differenciation and replacement).

A human being is conceived as the same, changeable, individual from birth 
to death. Its delineation remains rather self-evident at any stage, this is 
why we call it a real, observable, individual at any stage. It's a 
cohesive, concrete biological system at any stage.

But the cells, dead and alive, are not a concrete cohesive system. Dead 
cells are no more part of the real system of the present individual. Maybe 
it's sad news for Curtis  ;-)   but that's life, that's the real life process.
The "system" of all cells of Curtis Clark is a human construct, it is the 
imaginable (but not observable) collection of all these cells. Dead cells 
of your foetus don't interact with your present cells. You can't observe 
this, can you? The cohesion of this system of cells dead and alive is our 
biological concept of "cells of a same individual through its successive 
stages". But you can't observe an encounter between your foetus and 
yourself, can you? So this "longitudinal same individual" is not presently 
observable. It is a thought construct, it is the best scientific 
explanation of both your observable existence at the present time and the 
record of different occurences of a Mr Clark in the archives of mankind. It 
is an inferred history of biological continuity and transformation. It is a 
highly plausible history, it is not anything concrete (individual or 
system) anyone could "observe" properly.

Hence your comparison between the collection of your cells (all along your 
lifetime) and the individuals of species (attributed to the species all 
along the evolutionary process) has some validity, but the conclusion is 
not that both are observable: the conclusion is that both are inferred 
historical explanations of the data at hand (living, plus archives = 
possibly preserved biopsies like a tooth of the young Curtis or a pinned 
museum specimen).
No continuity of the descent process from generation to generation, no species.
No continuity of the cell cohesion, differentiation and replacement process 
through lifetime, no individual. This is the explanatory theory.
The change process is real and observable on a small scale: it is the 
succession of states in the changing individual, or changing population. 
The attribution of all the cells dead and alive, or of all the individuals 
dead and alive, to a same individual, or population (conceived on several 
generations), or subspecies, or species, or taxon, is an inference of the 
biologist, not an observation of a fairly self-delimited, concrete... hence 
observable system.

If I define "observation" as "observation of a concrete object or system of 
objects", then a species is not observed, only a presently living 
population can be, at best.

Note: this IS a refutation of the notion of species-as-individual (and by 
the way, of all-the-cells-of-Curtis-Clark-through-Curtis' 
lifetime-as-individual, too).

In another post, Curtis Clark wrote :

 >Something is "real" if scientists can study
 >it from different angles and get consistent results. The philosophical
 >issues are interesting in their own right (my degree does say *Ph*D, after
 >all), but I don't see that they directly affect what we do as scientists.

Of course the "spontaneous" materialist, and rationalist, and realist, 
philosophy of most scientists allows a fair development of science. But 
science-friendly philosophy (materialist, rationalist, realist, exact...) 
can help the scientist.

Example: should'nt we better distinguish "true" (of an explanatory theory, 
like common descent, e.g. belonging to the same species) from "real" (of an 
observable concrete system)?

Application: you can study a collection of specimens from different angles. 
The specimens are real, observable. You can attribute some of them to a 
same species (your criteria). The species is not observed. You have put the 
specimens in different boxes yourself. It's your scientific explanation of 
similarities and differences. It can be true, the species is still not 
observed (characters on every specimen are, but characters are not species, 
they are separate observable feautures). You can recheck another way and 
find the same result (you put the same specimens in the same boxes), the 
species is still not observed. And will never be. It's a historical 
explanation. You can't observe an explanation with present biological 
technologies (you should open a braincase, where the concrete process of 
thought occurs and is potentially observable, provided you can decode it).

Implications: science without philosophy is possible, but it is at a risk 
of misconceptions or erratic semantics; science subordinated to flawed 
philosophy (including logics) is the worst, mere communication between 
scientists may even be impeded and some research perspectives arbitrarily 
blocked (a strict creationist should hardly engage in studying evolution); 
science enlightened by and enlighting back sound philosophy is the best 
imaginable... But we evidently have still to work hard on this, and 
philosophers too!  ;-)

Cheers,
Pierre


Pierre Deleporte
CNRS UMR 6552 - Station Biologique de Paimpont
F-35380 Paimpont   FRANCE
Téléphone : 02 99 61 81 66
Télécopie : 02 99 61 81 88