Internal cause is the basis of things' change, and external cause is the condition of things' change.

The internal cause is the basis of the change of things, and the external cause is the condition of the change of things. This is materialist dialectics. Internal cause, that is, internal contradiction, is the basis of things' existence, the inherent essence that distinguishes things from other things, the basis of things' changes, the direction of things' development and the fundamental reason for things' development.

External cause refers to the mutual connection and influence between things, which is the condition for things to change. It can accelerate or delay the development of things, but it must work through internal factors. In a word, the internal cause is the basis of the development and change of things, and the external cause is the condition of the development and change of things, and the external cause works through the internal cause.

materialistic dialectics

Materialist dialectics, namely Marxist dialectics. Taking the most common laws of nature, human society and thinking development as the research object is an advanced form of dialectical thinking development and an important part of Marxist philosophy.

It is believed that the material world is a unified whole with universal connection and constant movement and change, dialectical law is the law of the material world's own movement, and subjective dialectics or dialectical thinking is the reflection of objective dialectics in human thinking. It is the most comprehensive, rich and profound development theory.

It includes three basic laws: the law of unity of opposites, the law of mutual change of quality and the law of negation of negation, and a series of basic categories such as phenomenon and essence, cause and result, necessity and accident, possibility and reality, form and content with the law of unity of opposites as the core. It is a kind of cosmology, epistemology and methodology.