Godišnji znanstveni skup
Filozofija i filodoksija

Zagreb, 19. i 20. prosinca 2002.
Velika dvorana Instituta za filozofiju
Ulica grada Vukovara 54/V

FILIP GRGIĆ
Nekoliko napomena o Aristotelovim nominalnim definicijama

Pretpostavimo da istražujemo P (pri čemu je P općenito predmet znanosti, recimo prirodna vrsta) i da nas zanimaju prvenstveno dvije stvari: da li P postoji i što je P. Stajalište što ga Aristotel razvija u Drugoj Analitici II.1-10 obvezuje ga na sljedeće. S jedne strane, da bismo znali što je P, moramo znati da P postoji. Iako Aristotel za to nudi kratak dokaz, čini se da on to pretpostavlja kao trivijalnu činjenicu. S druge strane, međutim, čini se da je on obvezan i na obrnutu tvrdnju: da možemo znati da P postoji samo ako znamo što je P. To ne slijedi samo iz menonovskog okružja njegove rasprave (ako istražujemo postoji li P, kako možemo znati postojanje čega istražujemo ako ne znamo što je P?); Aristotel je na to stajalište prisiljen i zbog nekih specifičnih tvrdnji što ih zastupa u APo. II.1-10. Naime, on smatra sljedeće: znati da P postoji znači moći demonstrirati da P postoji; moći demonstrirati da P postoji znači znati uzrok/objašnjenje od P, a uzrok/objašnjenje od P zapravo je odgovor na pitanje što je P: prema tome, znati da P postoji znači znati što je P. Što, dakle, prethodi čemu, demonstracija egzistencije definiciji ili obrnuto? Aristotel to smatra teškim i ozbiljnim problemom. Obično se pretpostavlja da on na njega pokušava odgovoriti tako što smatra da polazište u istraživanju egzistencije i definicije predstavlja poznavanje nominalne definicije od P, tj. znanje o tome što znači “P”. Prema jednoj varijanti tumačenja, znanje o tome što znači “P” ne uključuje znanje o tome da P postoji (ili znanje o tome da postoje instance od P), ali, budući da sadrži (nekakav) odgovor na pitanje što je P, omogućuje daljnje istraživanje egzistencije i (realne) definicije. Prema drugoj varijanti tumačenja, znanje o tome što znači “P” uključuje znanje o tome da P postoji (ili znanje o tome da postoje instance od P), a to je znanje dovoljno da bi se dalje istraživalo i došlo do demonstrativnog znanja o egzistenciji P-a i do njegove realne definicije. Veći dio mojeg izlaganja bit će negativan. Pokušat ću pokazati da Aristotelove nominalne definicije ne mogu obaviti tu zadaću i da nisu namijenjene tome da obave tu zadaću. Ponudit ću i skicu alternativnog rješenja problema.

A Few Notes on Aristotle’s Nominal Definitions

Let us suppose that we are investigating P (in which P is generally the subject of science, let us say natural kinds), and that we are primarily interested in two things: whether P exists and what P is. The standpoint developed by Aristotle in his Second Analytics II. 1-10 obliges him to the following. On the one hand, in order for us to find out what P is, we must know that P exists. Irrespective of the fact that Aristotle offers a short proof for the previous, it nevertheless seems that he presupposes the same as a trivial fact. On the other hand, however, it seems that he is also obliged to the contrary claim: we can know that P exists only if we know what P is. This does not follow from the Meno-like environment of his discussion alone (if we are investigating whether P exists, how can we know of the existence of what we are investigating if we do not know what P is?); Aristotle is forced to take this standpoint also due to certain specific claims which he represents in Apo. II. 1-10. Namely, he holds the following: to know that P exists is to be able to demonstrate that P exists; to be able to demonstrate that P exists is to know the cause/explanation of P; and the cause/explanation of P is, in fact, the answer to the question what P is: accordingly, to know that P exists is to know what P is. Thus, which comes first – the demonstration of existence or definition? Aristotle considers this to be a difficult and serious problem. It is most often assumed that the way in which he attempts to provide an answer to this question is through believing that the point of origin of the investigation of existence and definition represents the knowledge of the nominal definition of P, i.e. knowledge of the meaning of “P”. According to one version of interpretation, knowledge of the meaning of “P” does not include the knowledge of the existence of P (or the knowledge of the existence of instances of P), although, since it contains an answer (of some sort) to the question of what P is, it enables us to further investigate existence and (real) definition. According to another version of interpretation, knowledge of the meaning of “P” includes the knowledge of the existence of P (or the knowledge of the existence of instances of P), and this knowledge is sufficient for us to further investigate and arrive at the demonstrative knowledge of the existence of P and its real definition. The author’s paper is negative for the most part. He attempts to show that Aristotle’s nominal definitions can neither accomplish the above task nor are they intended to accomplish the above task. He also offers an outline of an alternative solution of the problem.