realism, anti-realism, and fictionalism regarding whether something exists or not, become obsolete. For example, schizophrenia may exist with respect to Eugen Bleuler (1857–1939) and his followers' language and logic, while Thomas Szasz and his followers may view it as a myth with respect to their language and logic. The only remedy for irreconcilable ontological controversies of this and similar type is to care about one's unkempt language and logic, and to reach an agreement about which language and conceptual system and which logic should be used in a particular scientific discourse. Anyhow, medical language and its sublanguages as ill-structured and ill-kempt workaday languages are absolutely unsuitable for serious discourses. They allow their users too much latitude in interpretation. "Change your language or logic, and you will see another world". His fuzzy ontology also includes a fuzzy mereology and mereotopology by means of which vague part-whole relationships, for example in anatomy, surgery and other medical fields, become logically tractable. In addition, he has developed a technique to bring to light the ontological commitments of any piece of medical knowledge so as to ascertain the ontological prerequisites of its satisfiability. He hopes to have paved the way thereby for a precise medical model theory in analogy to the mathematical one, which might enable sophisticated knowledge ontology in medicine and elsewhere, and thus, advanced medical epistemology. "In such a medical model theory, relationships between models of different items of medical knowledge, including theories, could be precisely analyzed". However, he is very skeptical about what has recently come to be known as biomedical ontology engineering in biomedical computer and information sciences. He does not regard this endeavor as ontology at all because it is actually concerned with vocabularies and terminologies confirming the slogan "ontology recapitulates philology".On page viii of his book Word and Object (paperback edition 1964), Willard Van Orman Quine attributes the sardonic slogan to James Grier Miller (ii) On medical truth. After a thorough discussion of truth theories, Sadegh-Zadeh shows that there is sufficient evidence to support the assertion that medical truths are system-relative, and are produced within the respective health care systems themselves. They do not mirror or report scientifically discovered facts in the world out there which could be independent of the conceptual system from where they are viewed and judged. This problem not only concerns truth in medical sciences, but also truth in clinical practice. Specifically, he precisely explicates