INUS조건과 원인 = 인공언어와 자연언어를 중심으로

국문 초록 (Abstract)

인과성에 관한 논의는 시대의 흐름에 따라, 논의의 대상과 방법에 따라 그 형태도 다양하게 나타난다. 이 논문에서 다루는 인과성의 대상은 자연 현상에 관한 기술개념(記述槪念)에 국한하였다. 분석방법으로는 과학적인 인공언어와 일반인들의 자연언어에 의한 원인분석을 택하였다. 전자에 의한 원인제시는 ‘언제 어디서나 요청되는 객관성을 띤 인과적인 필요조건들을 찾아내고, 그런 필요조건들이 모여 인과 충분조건을 이루고, 그런 충분조건을 주어진 현상이나 사건의 원인으로 간주하는 경우이다. 한편, 후자에 의한 원인분석은 주어진 상황이나 문맥을 중시하면서 그 속에서 가장 결정적인 역할을 한 요인을 찾아내어 그것을 나타난 결과의 원인으로 삼는 경우이다. 이것은 일상인들이 상식적인 수준에서 자연언어를 사용하면서 흔히 지적하는 원인제시방법으로, INUS조건에 의한 설명이 이에 해당한다. 하지만 이 방법은 무엇을 INUS조건으로 간주하느냐하는 점에서 사람들의 의견이 다를 수 있으므로, 이런 주관성에서 드러나는 문제점을 극복할 수 있는 기준설정이 요청된다.

다국어 초록 (Multilingual Abstract)

An INUS condition is defined to be an insufficient but necessary part of a condition which itself is unnecessary but sufficient for the result. For example, a short circuit might be a decisive and indispensable part of a complex sufficient condition for the grass-roofed house’s burning. In this case, the short circuit is called the INUS condition. Of course, other factors in addition to the short circuit are also required for the fire. At a glance, an INUS condition seems similar to a causally necessary condition in its property, but there are differences between them as follows. In the case of the causally necessary condition, oxygen is always an indispensable factor of fire under any circumstances. Oxygen is an indispensable common factor of fire, whereas the short-circuit isn’t. If there is no oxygen, there is no fire. But the short circuit is only an indispensable part of a complex sufficient condition of the fire in the given particular situation ― for example, ‘There is a wooden house’, ‘There is no suitably placed sprinkler’ and so on. The short circuit is not necessarily an indispensable part of other situations. There can be other kinds of INUS conditions for fire instead of the short circuit ― for example, gas explosion, striking a match, the light of a cigarette, a bolt of lightning, and so forth. According to J. L. Mackie, (AX or Y) is a causally necessary and sufficient condition for P. (AX or Y) causes P, but not vice versa. In this case, AX means a causally minimally sufficient condition for the result P, and Y the disjunction of all other causally minimally sufficient conditions for P. A is an INUS condition. He defined that the INUS condition is asymmetrical for the effect. (AX or Y) is also asymmetrical for the effect. (AX or Y) causes P, whereas not vice versa. This relationship holds in one direction between cause and effect, but not the other. There is no symmetrical relationship between (AX or Y) and P either. An INUS condition is based on subjective, ordinary language style, while a causally necessary condition is scientific. The former is easy to understand without scientific knowledge, but has problems about how to establish the criteria for the INUS condition because there might be different viewpoints. Furthermore, Mackie’s what is called a causally necessary and sufficient condition isn’t persuasive because a necessary and sufficient condition usually implies a biconditional