Contradiction

In dialectical materialism, a contradiction is formed when two requirements are met:

1. Two things must be diametrically opposed
2. And one cannot exist without the other

For example: in warfare, attack and defence form a contradiction; defence is the diametrical opposite of the attack (rule 1) and there is no need for defence if there is no attack (rule 2).

Note that diametrically opposed does not necessarily mean the literal opposite. Diametrical means the complete opposite, at both extremes. The bourgeoisie and proletariat are diametrically opposed (both existing at one extreme end: the bourgeoisie that controls industry and the proletariat that must work this industry), but they are not an antonym to one another.

Contradictions exist everywhere in the world and in many different domains, and it is the solving of contradictions (which makes new ones appear) that drive change in the general sense of the term, thus dialectics happen.

Mao Zedong talked at length about contradictions and is a good starting place for theory.

Primary and secondary contradictions

Contradictions are separated into primary and secondary categories. Secondary contradictions are dependent on primary ones for their existence or rather, primary contradictions drive secondary contradictions.

Whether one should solve the primary or secondary contradiction first is still a point of debate.

Some think that solving class contradictions for example (moving into communism, a classless society) will also inherently solve several secondary contradictions attached such as racism, homophobia, sexism, selfishness, etc.

For others, it is impossible to solve the primary contradiction without addressing the secondary contradictions. They argue it is simply impossible, for example, to solve class contradictions if sexism and homophobia are not addressed first.

Solving contradictions

A contradiction is solved when it stops existing; i.e. when both rules stop being applicable.

Thus the proletariat will stop existing as a class when the bourgeoisie stops existing. However, in that scenario, one of two things may happen:

1. Another contradiction takes its place
2. The contradiction is solved for good

In this example, it means that the proletariat may be replaced by another class -- but inevitably, so will the bourgeoisie (much like how serfs and nobles were replaced by capitalist social classes). Thus another contradiction would take place between these two classes. Or classes could stop existing at all, which would usher in a classless era and solve class contradictions for good (since there are no more classes).

Further Reading

Mao Zedong : On Contradiction