It is quite clear that the first two of Engels's so-called 'laws' are incompatible with one another. Here is how Engels characterised them:

However, according to Engels and Hegel, such 'qualitative' changes are 'nodal', that is, they aren't gradual, they are sudden:

And here is Engels:

Here, too, is Plekhanov:

Despite this, it is quite clear that the 'nodal' aspect of the first 'Law' is incompatible with the second 'law', the Unity and Interpenetration of Opposites (UIO), or at least the UIO is inconsistent with the DM-rejection/criticism of the LEM.

[LEM = Law of Excluded Middle; FL = Formal Logic; DL = Dialectical Logic.]

Here is Novack on the alleged 'laws' of FL:

Of course, Novack is just parroting Hegel and Engels here (all the while offering no evidence to substantiate his claim that Aristotle's logic (let alone modern logic) is based on these 'laws',or even that he (Novack) has got these 'laws' right!

[In fact, he and every other DM-theorist I have read (and there have been hundreds of these -- no exaggeration!) over the last twenty-five years has got these 'laws' wrong. On that, see here.]

For example, here is Engels on the LEM:

Now, I have shown (here and here) that the above ideas are far too confused to be assessed for their truth or falsehood, but the point I wish to make in this post is that the above 'law' (the interpenetration of opposites, etc.) is incompatible with the first law (the 'nodal' change of quantity into quality).

To see this, consider object/process P which is just about to undergo a qualitative 'nodal' change (a "leap") from, say, state P(A) to state P(B) -- for example, water that is just about to boil, and thus change from liquid to gas.

For there to be a 'nodal' change here it would have to be the case that P is in state P(A) one instant/moment, and in state P(B) an instant/moment later (howsoever these "instants/moments" are defined). There is no other way of making sense of the abrupt nature of 'nodal' change.

[To spare the reader, I will simply refer to these as "instants" from now on.]

Of course, we are never told how long such 'nodes' are supposed to last, which fact allows DM-theorists to include anything from an ice age to a quantum leap as a 'node', introducing an element of subjectivity into what is supposed to be an 'objective' law.

However, given the strife-riven and sectarian nature of dialectical politics, any attempt to tell us how long such DM-'nodes' are could lead to yet more factions. Thus, we are sure to see emerge the rightistNanosecond Tendency-- sworn enemies of thePicosecond Left Opposition-- who will both take up swords with the 'eclectic' wing: the "it depends on the circumstances" 'clique' at the 'centrist'Femtosecond League.

Be this as it may, if the above were so (i.e., if P is in state P(A) one instant, and in state P(B) an instant later), then any state description of P would have to obey the LEM, for it would have to be the case that at one instant it would be true to say that P was in state P(A) at that instantbut not in state P(B) at the same instant.

That is, it wouldnotbe true to say that P was inbothstates at once (which is, of course, a core idea of the DM-account of 'nodal' change). In that case, these two states would not interpenetrate one another, since the LEM would apply to this process at that instant: P must therefore be in state P(A)orstate P(B) (but not both) if the change from P(A) to P(B) is to be 'nodal', or "sudden".

On the other hand, if these two states do in fact interpenetrate one another (and the above conclusions are false) --such that the "either-or" of the LEM does not apply,which, we are told, it cannot do at a point of change-- and it were thus the case that P was inbothstates at once,then the transition from P(A) to P(B) would be smooth and non-'nodal', after all!

Now, this fatal dilemma is independent of the length of time a 'node' is supposed to last (that is,if we are ever told).

It is also worth noting that this inconsistency applies at just the point where dialecticians tell us DL is superior to FL --, that is,at the point of change.

So, once more, we see that not only can DL not explain change (on that see here), at least two of Engels's three 'Laws' are inconsistent with one another (when applied to objects/process that undergo change).