When Soemmerring attempted to prove that Negroes are physiologically inferior to Europeans he blatantly served a romanticism of supremacy. This becomes tangible when, on the first pages he admits that white people do entertain slavery; in the 1784 edition, he expressly named Russians and Poles, but a year later he made the excuse more vague, referring to Europeans. At the same time he added the monetary value of an African slave and some literary reference. These amendments give away that Soemmerring was not feeling secure in his task. It also sheds light on the subsequent treatise: a scientific justification of resentment. His physiological anthropology was expression of his supremacy romanticism.
Any romanticism is driven by resentment of the current state of affairs and reactionary in the sense of reacting to a threat perceived in the present situation with the impulse to regain territory, restore a status quo ante, or at least to conserve the status quo. What might have frightened Soemmerring? Most likely the results or the theoretical framework of his research. His studies on brain anatomy had led to a stage of interpretation that severed the mind of all human and moral properties. Therefore he had to find a human group that in being inferior elevated the Soemmerring's group. It is revelatory how he employed the first person grammar in vindicating humanity of Negroes: "Um allen gehäßigen Schlüssen und Mißbrauche vorzubeugen, wiederhole ich nochmals, die Negern sind wahre Menschen, so gut wie wir", and he adds with a wink to his gentlemen readers, "als eine der schönsten Griechinnen."
Why this reference to the first person; why could he not say something like "as truly human as any European"? My interpretation is: whenever philosophers and scientists refer to themselves as the touchstone of their theory, they are vindicating a lost supremacy, lost through their own investigation and the resulting theory. We are not talking about Descartes' ego cogito, because he thematized the need to reduce the theory of the world and of consciousness to the "I" of the philosopher. (He may have been wrong in doing so, but that is not the matter here.) We are not talking of philosophical subjectivism, as in Kant's transcendentalism, which inevitably has to establish an ego as the locus of thought. We are dealing with scientific investigation into matters at hand, established facts, and objects of research, where every now and then slips in an I.
Peter Geach, for instance, while explaining Plato's theory of immortality said: "It appears a clearly intelligible supposition that I should go on after death …" Wait, to whom is that intelligible? To his credit, Geach immediately after that plays with the notion of him, Peter Geach, surviving or not with or without body. So it is justified that he assumes the first person perspective in order to show the paradoxes of identity in immortality. And yet, is it inevitable to discuss the immortality of the soul in first person? I should say, no, it is even wrong. As Geach argues, the ontological status of the soul after death is so different from that of the soul as the identity making feature of a living person that it is impossible to apply experience to the immortal soul. Experience is first person experience. Hence it is wrongheaded to use the first person perspective when discussing immortality. As Geach says, the claim "But if I went on being conscious, why should I worry which body I have," should be rephrased as "If there is going to be a consciousness that includes ostensible memories of my life .." This language is "fairer" (p. 20), because it addresses the fundamental distinction between the embodied self and the immortal consciousness.
So what is the power of temptation of the "I"? It is holding on to what is slipping away. The first person claim is the attempt at recuperating what is lost in the debate.
 Michael Hagner, Homo cerebralis. Der Wandel vom Seelenorgan zumGehirn, Frankfurt: Surhkamp, 2008, p. 67. S. Th. Soemmerring, Ueber die körperliche Verschiedenheit des Negers, Frankfurt/Mainz: Varrentrapp, 1785, p. XX.
 Peter Geach, "Immortality," in Immortality ed. Terence Penelum, Belmont, California: Wadsworth, 1973, 11-21; 13.