We must discuss the degrees of extinction to preserve scientific knowledge and to protect traditional cultures as their interpretation of the world and their means of maintaining memory of the past

We must first discuss the extinction of populations and make clear the sharp contrast with the notion of species’ extinction. What is the extinction or disruption of a population? Because we said that a population is an individual, we should try to understand a population’s extinction in comparison with individual death. This will be done with the help of the examples and discussion on death presented by in Biological individuality. – A population could go extinct with the death of all its members. Here, the extinction is the ‘death’ of the population, understood as the final death of an individual. – A population could go extinct with the cessation of all effective relations between the members of the population (as when the organisms of one population are dispatched in many other populations). We are clearly in the situation described by , of a functional extinction. But, is the population ‘dead’? Yes, but in the sense that its life has been ‘suspended’ as writes. This situation is the analog for populations as cryptobiosis for organisms (). The individual remains numerically and materially the same, however without relations. The population can live again if the relations are recreated between the same individuals. A population can thus go extinct in dying by disruption on two levels (intra-organismic and inter-organismic) and can, in the latter case, be brought again to life as long as it still exists numerically. But a population cannot be recreated after the extinction due to the ‘disruptive’ death of its members as in the first case. Clones recreated from the genomes of the last members of the population would be other organisms and thus the population of clones would be another population. Thus we end up with two different ‘degrees’ of populations’ ‘death’. Concerning species, we have already described four modalities of extinction at the beginning of this article, and yet we present below what we call three ‘degrees’ of conceptual extinction. The first is the ‘objective’ extinction degree when the species becomes a null class (whether by phyletic or non-phyletic extinction). The second degree of extinction, made possible by the artificial creation of clones from entire genomes, concerns the extinction of genetic information coming from the members of the species. As long as we can expect for technical reasons that a member of an extinct species can be recreated, we can say that the species is ‘virtually non-extinct’ or ‘potentially non-extinct’ to refer to the Aristotelian vocabulary. Here the natural telos is of course replaced by a human and technical finality. The third and last degree of extinction is related to the extinction of the meaning of the species. More than organisms or genomes waiting to be saved to alleviate human shame, species have their own signification and existence as primary members of our perceptive, cognitive and symbolic universe. A species would thus go extinct (for us) in the sense that it existed as an abstract category (‘good to think with’, as , demonstrated) and disappeared from our understanding with the loss of information and representation about this species. This is probably the kind of extinction to which Lyell was sensitive when he spoke of the dodo, like Strickland, Lyell’s contemporary, a great ornithologist who was the first to write an entire book on the dodo and who sought consolation in this view of the naturalist’s duty: ‘It is, therefore, the duty of the naturalist to preserve to the stores of science the knowledge of these extinct or expiring organisms, when he is unable to preserve their lives; so that our acquaintance with the marvels of animal and vegetable existence may suffer no detriment by the losses which the organic creation seems destined to sustain’ (). To fight against this kind of extinction, the disappearance of a species as an abstract or a virtual category, is also a way to protect traditional cultures as their interpretation of the world and their means of maintaining memory of the past are supported by the natural categories ().