Marx defines truth in a pragmatic way. The truth value of a judgement is due to the usefulness of accepting or rejecting the judgement. A statement is true if accepting it makes a positive difference or has a helpful influence and it is false if accepting it causes difficulty or dissatisfaction. The meaning of a statement is the practical result of accepting the statement. In general, then, the truth or falsity of a statement is relative, not only to the individual accepting or rejecting the statement, but also to the circumstances in which that person finds himself.
Humans are in contact with nature at a fundamental level.
The human understanding of nature is a consequence of the fact that nature confronts humans when they try to fulfill their needs. This is the case with any organism, and each species reacts according to the tools of that species. One of the human tools is the intellect, and it works through the cognition of the perception of elements of nature. Cognition occurs as the organizing of sensory data into categories. Without the ability to make generalizations, man would not be able to think.