unding 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, differing only in being even more general, then that simply exemplifies confusion in the use of the words "law" and "general" (admittedly very confusing words), since the latter are empirical laws and the former are not. There is not a shred of evidence to suggest that Engels was actually guilty of any such confusionthat he really thought that, for example, the "law of transformation of quantity into quality" was a transformation law of the same logical type as, say, the first law of thermodynamics. Some of his interpreters did afterwards perpetrate such confusionbut Engels himself simply did not deal with such logical questions, which had not yet been raised at the time he was writing. The point can, if one likes, be put like this—that the difference between these laws is not only a quantitative difference, of degree of generality, but a qualitative difference; they are different kinds of law, or exemplify different uses of the word "law".
Perhaps the difference can be most perspicaciously brought out in terms of Dr Popper's criterion for a "scientific" (or empirical) law. Such a law, he said, must be falsifiable. Sure enough, the laws of thermodynamics, for example, are falsifiable, even though never actually falsified. But principles or laws concerning categories, including "the most general" ones, or universal "laws of dialectics", are not falsifiableor if they are, they are not correctly formulated. For instance, certain scientific or empirical laws stating and forecasting how particular changes happen state and forecast how certain quantitative changes bring about certain qualitative ones. Such laws are subject to empirical test (falsifiability), as to whether the connection of qualitative with quantitative change is always in fact as stated. But that qualitative and quantitative changes are always connected is not similarly subject to test. That they are connected in a particular way in a particular case has to be empirically established or disestablishedbut not that they are connected. Thus "the law of th