Resulta que la conversación llegó a su cumbre cuando el Colega me dijo : "Yo no dudo que haya un fundamento ontológico del Modus ponens"...(y no supo más qué decir).
Me pareció de buen gusto finalizar ahí esa discusión inútil y pensé que encontrar el fundamento ontológico del modus ponens era una tarea tan fantasiosa como completar el Árbol de Porfirio por el lado derecho.
Sin embargo, en un artículo que aparecerá en el 2014 (The Metaphysical Interpretation of Logical Truth
TUOMAS E. TAHKO) aparece el fundamento metafísico realista del Modus Ponens. Se los comparto.
"Very briefly, we might consider the case of modus ponens (A∧(A→B))→B). If
thought of as a rule, it may seem difficult to apply it to the world in the sense that I have suggested with regard to LNC. (1) Yet, there do appear to be clear cases of physical phenomena that feature a modus ponens type structure. As a first pass, causation might be offered as a candidate of ‘real world modus ponens’, but there are obvious complications with this suggestion, as it depends on one’s theory of causation. However, there are, perhaps, better candidates. Take the simple case of an electron pair in a closed system, where two electrons occupy the same orbital. As we’ve already observed, two electrons in a closed system are governed by the Pauli Exclusion Principle. In particular, since the electrons cannot be in the same quantum state at the same time, we know that the only way for them to occupy the same orbital (i.e., having the same orbital quantum numbers) is for them to differ in spin (i.e., to have different spin quantum numbers). Accordingly, when we observe electron A having spin-up, we immediately know that any electron, B, on the same orbital as A must have spin-down. Moreover, there can be only two electrons on the same orbital and they must always have opposite spin.
It is easy to see how this situation could be interpreted as a real world modus ponens type case. Even better, we only needed to refer to one fundamental physical principle to make this case."
(1) (LNC) The same attribute cannot at the same time belong and not belong to the same
subject in the same respect and in the same domain.
La verdad es que no me convence....