Practice, as a criterion for testing the truth, is uncertain and refers to relativity. Practice is all human conscious actions. The contradiction between inner consciousness ontology and life ontology is the fundamental contradiction to promote human self-liberation, and its externalization is the liberation activities of human individuals, organizations and class as a whole, and between individual or collective relations and class relations, which are connected with nature through production relations. Practice is human nature and personality only under conscious consciousness, that is, as the saying goes: practice makes true knowledge.

Expansion: a famous saying about truth

I love my teacher, but I love truth more. -Aristotle

Fighting for the truth is the greatest pleasure in life. Bruno

Man needs truth just as the blind need a bright guide. Gorky

People should love truth and accept it as soon as they see it. -Goethe