Engels discusses this topic in Chapter XI, Part I of Anti-Dühring (Morality and Law. Freedom and Necessity). Dühring claims to discuss the problems of law and politics with knowledge gained from "the MOST EXHAUSTIVE SPECIALIZED STUDIES." And he contrasts his own in depth studies with the "admittedly neglected legal studies of Herr Marx."
Well, if Thomas Henry Huxley was Darwin's Bulldog, Engels was Marx's and nothing sets him off more that Dühring's propensity to portray himself in a favorable light at the expense of Marx, especially when Marx's knowledge of the subject matter under review was many magnitudes greater than the paltry speculations put forth by Dühring.
In his discussion on law and politics Dühring begins by making sweeping generalizations about the law in general, such as that "revenge" is the basis of criminal law, and then moves on to comparisons of French law with the Prussian 'Landrecht'-- all of which reveals that Herr Dühring knows very little about these matters. He seems ignorant of the fact that French law,that is, modern civil law [outside of England] "rests on the social achievements of the Great French Revolution" as embodied in the Code Napoléon.
Dühring puts himself forward as a great student of the law, but Engels points out that he is not only ignorant with regard to French law, but that his ignorance carries over to Roman law and even Germanic law (especially its English version "which is the only Germanic law which has developed independently of Roman authority up to the present day and spread to all parts of the world....")
Dühring's form of socialism has another great defect and that is his rampant anti-Semitism. Engels says "his hatred of the Jews" is carried "to ridiculous extremes" which he "exhibits on every possible occasion." Engels really takes Dühring to task over this issue. Dühring thinks that hatred of Jews is based on "natural grounds" and is a "natural judgment" while Engels says it is a wide spread prejudice "inherited from the bigotry of the Middle Ages."
What is worse is that Dühring thinks one of the arguments in favor of "socialism" is that it will lead to better methods of Jew control. These are Dühring's words: "socialism is the only power which can oppose population conditions with a rather strong Jewish admixture." Engels sums up his view of Dühring's opinions as those of a man full of "grandiloquent boasts" and exhibiting "the crassest ignorance."
At this point Engels remarks that when dealing with questions of morality and law it is hard to ignore the question of "free will." Are all our actions predetermined or can we be held responsible for them? Herr Dühring gives two, conflicting, answers to this problem. His first answer is that there is a tug of war in the mind (brain) between instincts and reason. Our instincts pull us one way and reason another. The more rational we are, the more educated and subject to reason, the less we will be subject to the irrational emotions driven by out instinctual impulses. Dühring thinks this explanation will do away with the silly notion of "inner freedom." Each individual's behavior will be determined by his or her proportion of rational to irrational "drives".
Engels does not really evaluate this first answer, but says it is blown out of the water by Dühring's second answer. Engels quotes Dühring: "We base moral responsibility on freedom, which however means nothing more to us than susceptibility to conscious motives in accordance with out natural and acquired intelligence. All such motives operate with the inevitability of natural law, notwithstanding an awareness of possible contrary actions; but it is precisely on this unavoidable compulsion that we rely when we apply the moral levers."
I think the problem is this second answer ends up with "unavoidable compulsion." Yet the first answer also says about the same thing. The tug of war between reason and unreason will be resolved by the preponderance of the strength of each force within the individual. Engels calls it a "parallelogram of forces" resulting in the action taken being a mean between them. So perhaps Engels overstates the case that Dühring's two answers contradict each other.
Be that as it may, Engels is really interested in the second answer. It is not, he says, the result of any original thinking on the part of Dühring. It is a dumbed down version of Hegel, as is so often the case with Dühring's views. It was Hegel who "was the first to state correctly the relation between freedom and necessity". "Necessity," Hegel wrote, " is BLIND only IN SO FAR AS IT IS NOT UNDERSTOOD."
Engels explains that. FREEDOM is knowing what the laws of nature are and how we can use them "towards definite ends." This is true both for the natural [or external] realm (physics, chemistry, etc.,) and for the inner or mental realm. These two sets of laws can be separated conceptually (the physical and mental) but they are actually one set in reality. "Freedom of the will therefore means nothing but the capacity to make decisions with knowledge of the subject."
This means the more knowledge you have, the more educated you are about the things you are dealing with the FREER you are in dealing with them and at the same time the more NECESSITY comes into play-- i.e., of knowing what necessary actions must be done to attain the goal sought. Engels says, with respect to the will, "the uncertainty, founded on ignorance, which seems to make an arbitrary choice among many different and conflicting possible decisions, shows precisely by this that it is not free, that is is controlled by the very object it should it self control. And since freedom increases with knowledge of the world it, like equality, and law and morality, is "necessarily a product of historical development."
The greatest liberation from natural necessity of humankind on record, yet still strictly determined by physical laws, was the discovery of how to make FIRE: "the generation of fire from friction." Engels says that in our [his] age we might think the greatest advance in human control of nature, and thus in freedom, was the invention of the STEAM ENGINE and the modern world that it has made possible. We would be wrong. Fire was the very first of the forces of nature that humans began to learn how to control and it was this feat of "man" that "thereby separated him for ever from the animal kingdom."
Nevertheless, the invention of the steam engine was a great leap forward. Engels thought that the steam engine had so increased the productive forces of humankind that we could, in the age of steam, solve the social problem. For the increase in the PRODUCTIVE FORCES "alone make possible a state of society in which there are no longer class distinctions" in which there be will enough socially created product for all and "for the first time there can be talk of real human freedom"-- that is, "of an existence in harmony with the laws of nature that have become known."
Well, if we are threatening to destroy our environment, killing the oceans, and destroying the last of the oxygen producing rain forests (the lungs of the planet) and billions of people are facing starvation and famine, something has gone amiss in the last century and a half and we are definitely out of sync with the laws of nature while the increase in the productive forces is bringing servitude not freedom to masses of humanity. Engels vision is on hold.
Engels, however, was no utopian socialist, and would not have been shocked if he had been told that the human race was still many generations away from his musings on the attainment of "real human freedom." He had a longer time frame than many of his erstwhile followers who throw in the towel whenever there is a major setback. "But how young the whole of human history still is," he wrote, "and how ridiculous it would be to attempt to ascribe any absolute validity to our present views, is evident from the simple fact that all past history can be characterized as the history of the epoch from the practical discovery of the transformation of mechanical motion into heat up to that of the transformation of heat into mechanical motion." Engels' views are, of course, not absolutely valid, but I see nothing that has happened in the miniscule slice of time that has expired since he expressed them and the present day which would lead one to think they are out of date.