ules of qualitative and quantitative determination and their connectionthe so‑called "law of the transformation of quantity into quality". What is subject to qualitative determination is subject to quantitative determination, and vice versa; and these are so connected that alteration of the one is not independent of alteration of the other. Again, there belongs too the investigation of the so‑called "unity and interpenetration of opposites" and of "dialectical contradiction". To describe processes, motions and operations always involves the deployment of polar oppositions, such as "attraction and repulsion", "increase and decrease", "growth and decay", "addition and subtraction", "forwards and backwards", and so on.
But investigation of universal laws of dialectics remains an open field. It is something that has been projected but not yet systematically done. And the laws that have been written down, following Hegel, still lack both the precision of formulation and the systematic derivation to be expected of anything that can rank as science. The laws of dialectics should be, as Engels claimed, "as simple and clear as noonday". If they are not, and if their interconnection is not evident, that is because not enough work has been done on their formulation. (A case in point is the so‑called "law of the negation of negation".)
This may perhaps be thought a great failing. But to work out reliable theory it is not necessary first to work out all the principles which reliable theory exemplifies. On the contrary, no more than you have to work out all the laws of locomotion before you can walk do you have to work out all the laws of thought before you can think. It has been reported that Marx was always meaning to write a systematic treatise on logic and dialectics. But he never did. And even if he had tried, he might not have succeeded. For such an enterprise calls for a lot of highly specialised work, and most of this was done afterwards, and some of it by linguistic philosophers. To deal with dialectics requires a grounding in formal logic. Engels did make a few remarks about formal logic in his notes for the Dialectics of Nature, as well as about mathematics in Anti‑Dühring; but today these date badly. The well known practicality of Marx: prevented him from writing his treatise on logic and dialectics, not only because as a practical man he had other things to do, but also because it is never practical to undertake tasks for the fulfilment of which the conditions are not ripe. For the same reason he never tried to work out the detailed principles of socialist planning, which his followers now have to wrestle with. But what he did work out provides a secure starting point for socialist planning and socialist philosophy alike. He did establish the dialectical materialist approach, leaving it to his successors to work out the abstract principles of its logic as that becomes necessary for purposes of understanding, criticism and further development.
4. THE LAWS OF DIALECTICS
I have already remarked that the findings of an investigation of categories are distinguished from the propositions of formal logic in that they are not formal, and so are not to be symbolically constructed and tested in the way logical formulas are. But they are not empirical generalisations, and so are not comparable with even the most fundamental laws formulated by empirical sciences. For instance, the laws of thermodynamics deal with transformations of energy from one form into another. But "the law of the transformation of quantity into quality" is not a comparable law, just as "transformation of quantity into quality" is not comparable with "transformation of mechanical motion into heat". These exemplify different uses of the word "transformation".
In the Dialectics of Nature Engels called the laws of dialectics "the most general laws", and said that they were "abstracted" from "nature and human society". But if he meant, or is interpreted as meaning, that laws of dialectics are comparable with, say, laws of motion as formulated by Newton or Einstein, 