This paper deals with the question of how the process of digitalisation on the technical basis of the computer can be described in Marxist categories and what consequences are foreseeable as a result. To this end, the first section shows, based on a historical analysis of the emergence of the computer, that this apparatus was invented as an instrument of a division of human mental labour and thus complementary to the division of physical labour. It is therefore necessary to analyse computers and digitalisation in their relation to human beings and human labour. In the second section, the central ideology of digitalisation is elaborated, which is supposed to make the current form of digitalisation appear meaningful for people and society: The anthropomorphisation of the computer, which was said to be increasingly able to think, speak, and learn like humans, to become more and more intelligent, and to be able to do everything better than humans once the technical singularity had been reached. This claim, which has been propagated again and again, is contradicted on various levels. The computer operates on about two dozen simple mathematical, logical, and technical commands and can do nothing but run one programme at a time, developed and entered by programmers on the basis of behavioural or physical data. This sometimes produces amazing results because the computer can work quickly and systematically as well as reliably. But in contrast to humans, it faces the world as a behaviouristic machine that can neither understand meaning nor reflect its own or human behaviour. The computer also ”sees” and ”hears” its environment only on a physical basis and it ”thinks” at best on a statistical basis if the programme tells it to do so. The apparatus can therefore simulate mechanical machines, but in interaction with humans its actions and reactions are, as any machine, not socially oriented, but dependent on whether humans interpret them as meaningful und useful. The third section elaborates on the complementarity of mental and physical divisions of labour. This would be a central theme of a critical Marxism for an analysis of digitalisation today, which understands the previous capitalism from the division of physical labour. Even though there are some theoreticians who have contributed to this, so far there is no comprehensive theory of it. Therefore, section 4 wants to contribute to such a theory by collecting empirical observations in an interpretive way regarding the related questions. In this way, it becomes clear how the division of people's intellectual labour made possible by the computer is being dealt with today: Capitalism is reorganising more and more areas of human life such as mobility, social relations, education, medicine, etc. through the use of the computer. As a result, first and foremost the business fields of the digital economy are expanding. Moreover, capitalism no longer has to limit itself to controlling the field of production but is increasingly intervening in the whole symbolic world of people. Consequently, according to the thesis, we are heading for an expanded capitalism that will increasingly restrict and reduce both democracy and people's self-realisation. Section 5 emphasises once again that a different digitalisation is also possible, one that serves humanity and not capitalism. Further, some summarising and comments are added there.