According to Marxist Philosophy, the development and changes of things is caused by the internal cause and external cause and the internal cause is the decisive cause. The decline of natural law school in 19th century can be attributed to internal and external causes, and the internal cause may be the root cause.%马克思主义哲学认为，事物的发展变化，是由其内因和外因引起的，其中内因起决定性作用。自然法学说在19世纪走向衰落，也是由内外因共同作用的结果，其中内因可能是导致其走向衰落的根本原因。
展开▼
