A consistently materialistic conception, consistently adhering to a materialistic interpretation of the process of development as well as of the facts involved in the process, could scarcely avoid making its putative dialectic struggle a mere unconscious and irrelevant conflict of the brute material forces. This would have amounted to an interpretation in terms of opaque cause and effect, without recourse to the concept of a conscious class struggle, and it might have led to a concept of evolution similar to the unteleological Darwinian concept of natural selection.
Source: wiktionary