The benefit side

Discussing chimerism research in a consequentialist framework would not make much sense if one would take the side of possible benefits of this research out of the equation. I will not extensively comment on the benefit side of this analysis, though, but rather give some introductory remarks in this regard.

The potential or actual benefit of experiments involving interspecific entities varies greatly – which is true for any basic, not yet directly therapeutically applicable research. Looking at Irving Weissman's (proposed) work, for example, I find it to be quite plausible that the development of disease models like the "human neuron mouse" could offer many advantages regarding the improvement of our knowledge of how brain stem cells work to advances as tangible as screening of psychiatric drugs in a environment similar to a human brain. Greely's working group comes to a similar result when assessing potential benefits of Weissman's experiments.286

On the other hand, there are chimerism experiments that seem to have no benefit apart from satisfying the curiosity of the researcher. Andrzej Tarkowski, a Polish embryologist and pioneer of mouse chimera research,287 _{notes in his recollections regarding interspecific}

(animal to animal) chimera experiments:

286 _{Greely, Cho, et al. (2007b), "Thinking About the Human Neuron Mouse", American Journal of Bioethics,}

7(5), p. 32.

"For those who love experimenting in general, and in whom the childish curiosity and fantasy have not been yet completely ousted by logic and coolness of a respectful adult scientist, this is a wonderful experiment to do, but…(see below). (…) Although creation of interspecific mammalian chimaeras is indeed a spectacular experiment, in the author's opinion its contribution to embryology and genetics of mammals has been rather limited and disappointing."288

The creation of interspecific (nonhuman) chimeras has turned out to be of almost no use for the embryologist, apparently. I say "turned out" since, as in all areas of research that are still in their infancy, it is impossible to predict what kinds of benefits one might one day reap from them. An area of research that seems highly promising today might turn out to be a dead end in the future, as cross-species chimerism research apparently has for embryology. Also, it is imaginable that research results that might today seem only accessible via chimerism research might, at some point in the future, turn out to be researchable by other means – chimerism experimentation might turn out to be a detour in retrospect.

A prognosis of the future successes of basic research notoriously carries pronounced uncertainties. It seems extremely hard to make any useful statement on whether interspecifics research as such, or certain areas of it, e.g. human-animal chimera or cybrid research, will reap benefits. Even regarding specific experiments, it might prove to be impossible to sensibly predict whether they will, in retrospect, turn out to have promoted scientific success in a meaningful way. This uncertainty runs deep in the character of basic research.

I will assume here that the odds are somewhat skewed towards the point of view that the bulk of research done, in the long run, is reasonable or justified in some way. The reasons for this assumption pertain not to special moral qualities or benign intentions of scientists, but to pure mechanics of the research industry. Scientists, who are confronted with a situation of scarcity – funding for basic research is hard to access – are generally not interested in wasting money and time on unjustified or unreasonable experimentation, because this would hardly further their own long-term financial and status-related interests. These advantageous mechanics, evidently, can get skewed over short periods of time or in some areas of research. For example, the crude and dangerous "revitalisation" therapies of the 1930s (see p. 23) probably do not jump the hurdle of reason; neither does Ivanov's

288 _{Tarkowski (1998), "Mouse chimaeras revisited: recollections and reflections", International Journal of}

work regarding the hybridisation of human and ape (p. 30).289 _{The benefits of these}

(ultimately botched) ventures were not immediately tangible even at the time they were tried. I deem these cases to be rare exceptions from the rule that researchers usually, on average, have good reasons to believe that what they do will probably result in concrete scientific or medical benefits (this does not imply that I believe they necessarily will result in such benefits in all cases).

My assumption of overall reasonableness may sound trivial, yet I believe that stating it openly is important. Some popular objections to the creation of interspecifics (including the "hubris" concerns of section B.2.b above) work with or even crucially rely on the topos of the "mad scientist" who is completely cut off from common sense and allegedly does everything he does "simply because it can be done".

My analysis of consequentialist concerns will, from now on, concentrate on the cost side of the calculation, as this is what the debate focuses on. What bad consequences does (or could) interspecifics research lead to?