Real Species

[SKÁLA Zdenek]

Thanks to Pierre I believe the things are becoming more clear. As far as I understand the (majority of the) problem is boiling down to the questions:
1 - Is the (biological) interaction necessary and sufficient condition to qualify "concrete biological whole"? (to quote Pierre)
..which leads to another question:
2 - How to conceptualize "biological interaction"?

As concerns the 1st question, Richard Pyle raised important points in his last message: (1) members of populations are (mostly) not interacting so much to establish "cohesion" this way only, (2) the common descent of members of a population is important in this respect.
Moreover, *any* interaction has a temporal dimension (be it miliseconds or years or...). So, no interaction is "directly observable" (not speaking about the system of intrapopulation interactions as a whole) and the distinction between the 2_seconds_old state and 2_million_years_old state is more or less a matter of taste. Hence (and this is relevant to the 2nd question too), we cannot view interaction as a timeless connection of individuals but always as historical (yet on a fine scale) process with a clear signal-related donor-recipient polarization (no matter that this cycle can reverse many times in a "dialogue"). Thus, the hereditary relations are not fundamentally different from other signal transmission in this respect (despite they are specific in other respects), I must insist -  in any interaction, there is some individual that is the "final recipient" (like the offspring in heredity).

However, much of the species/population distinction relates to the "dead_member_of_a_whole" question, not exactly to the temporal dimension of interaction as such. I believe that this problem is in semantics: probably nobody here thinks that the dead organisms are members of a species in the strict way. Perhaps no paleontologist really thinks that those pieces of stones really *are* trilobites when he determines it as "species XY" - this is simply the short description of the fact that this is a trace of animal that was (once, when living) a member of the species XY. Shortly, the species Zea mays is still the same species as was 10 years ago - just because its concurrently existing members (individuals) are and has been interacting and all this system of interactions is moving forward in time (thanks to all types of interaction including but not restricted to heredity). So the fossil individuals are not currently members of the species but they were (when alive) members of the same species that is observed today (conceptually, methodological problems apart). 
It seems to me that all the population/species distinction has been driven by an overemphasis placed on (1) "almost timeless" nature of interaction and (2) direct observability of concurrent events.
Can we agree here?

Richard Pyle raises another important point however:
"Zdenek Skala refers to "natural" species (as distinguished from "taxonomic"
species), and my question to members of this list is, can units of "species"
(collective sets of individuals) be identified purely through "natural"
cirteria (i.e., with zero indication by a "classifying brain")?"

Very good question. Indeed, no classification, despite called "natural" or "taxonomic" is possible outside a classifying brain and without "artificial" criteria - all the concepts like "biological species", "phylogenetic species", "cohesion species" etc. are just human concepts. Hence, what we really do are different conceptualizations of what is "observed" (with all the necessary conceptual load even within the perceptions). Then, a fully legitimate question is: why is e.g. a group of interacting/mating individuals (or a monophyletic group) considered more "natural" than e.g. group of individuals below 30cm in height? Possible answers lead us back to the realism/nominalism distinction: either we will resign to a realism (and can easily find that what we earlier considered "artificial" classification can be more informative than what has been considered "natural" one) or will try to develop some concept(s) of "coherent wholes", "real things" etc. - with all the necessary conflicts with purely formal reasoning.

Best and thanks to all!
Zdenek Skala
skala at incoma.cz