invitation to further explore the questions that, as is typically the case with that
of evolutionary origins, have tended to remain in the background because their
specificities have not been sufficiently recognized.
5.5 Conclusion: Some Philosophical Consequences
Let’s end this section by drawing three philosophical consequences from this
exploration of neuroimmunology. First, neuroimmunology offers useful
(although not unique) lessons about interdisciplinarity. Two types of interdisci-
plinarity are found in neuroimmunology: horizontal (integration of different
disciplines–here neurobiology and immunology, to which one must actually
add endocrinology and psychology) and vertical (integration of different levels
of analysis, from molecules to systems, pertaining traditionally to distinct
domains). Neuroimmunology also illustrates exemplarily the well-known fact
that disciplines create mindsets and even norms of judgement and action. These
mindsets are difficult to overcome in basic research as well as in the clinic. For
example, few immunologists think about using neurostimulation to cure
patients with autoimmune diseases, and until recently few psychiatrists con-
sidered using immune-based therapies to treat mental disorders. In addition to
such epistemological questions, interdisciplinarity in neuroimmunology raises
an ontological question: are there really three systems (nervous, immune,
endocrine) in animals like us, or, as suggested, for example, by (Steinman
2012), are those only projections of our thought and language on the world?
Personally, I see the epistemological issue as more stimulating and pressing than
the ontological one, but both may converge to a large extent.
Second, what has been said here confirms the importance of adopting an
extended view of immunity, as argued in the previous sections. In the context of
neuroimmunology this extension has two dimensions. Thefirst dimension has
to do with the diversity of activities achieved by the immune system. To the
various immunological activities already identified in the previous sections
(development, clearance of debris, repair, and so on) one must add that the
immune system could also influence the nervous system and cognitive func-
tions. The second dimension is that the immune system is extended in another
sense, namely insofar as it is connected with other systems (here the nervous
and endocrine systems) and sometimes overlaps with them.
Third, our discussion suggests that immunology makes a significant contri-
bution to the understanding of behavior and cognition and should therefore
attract the attention of philosophers of neuroscience and philosophers of cog-
nitive science. If the experimental results presented above are correct, then the
immune system influences various feelings, behaviors, and cognitive processes
Philosophy of Immunology 61