The "Old" View(s) of the Laws: There is a lot of evidence from ancient (although not classical) sources that Plato wrote the Laws in the later part of his career . Diogenes Laertius claims that the Laws was Plato's last dialogue and that Philip of Opus transcribed it (see my recent blogpost). Similarly Plutarch,who may have been Diogenes Laertius' source, says that Plato wrote the Laws as an old man (De Iside et Osiride 370ff). The 19th century view took this to be sufficient evidence to place this not only as his last work but as the great culmination of his thought. The evolutionary hypothesis posits that the Laws rethought the Republic in a more practical manner.
Richard Kraut (whom I spoke about length in previous my previous blogpost) defends the hypothesis that the Laws was written last among Plato's works  and the stylometric analysis which places the dialogue based upon the Laws being the last and the latest of Plato's works. This seems to be the typical modern interpretation of the dating of the dialogue. Glenn Morrow cites a slightly more radical version in his book Plato's Cretan City, suggest that certain contradictions in the Laws imply that the Laws was an unfinished text at the time of Plato's death (Zuckert 96 footnote 95). Neither of these authors, so far as I know (I have not read Morrow's book, only what Zuckert quotes of it), employs the common wisdom that the Laws is more practical than the Republic, but this is still a commonly held view.
Zuckert's Dramatic Date for the Laws (460-450 BCE): A perhaps not-easily-noticeable, but quite unexpected, aspect of the Laws is that in a conference of three old men, a Creten, a Spartan, and an Athenian, is that there is no mention whatsoever of the Peloponnesian War (Zuckert 53-54). How is it possible that these three would talk so civilly, and the Spartan listens so earnestly to the advice of the Athenian (which seems unlikely with the tensions of the Peloponnesian War and certainly seems problematic if the dialogue is supposedly set in 408 BCE (as the comment hypothesized) or late in Plato's lifetime .
There are also any number of other things that Place the dialogue before the Peloponnesian War . The mathematics (Zuckert 54-55) are distinctly Pythagorean in nature and are not the type of calculations that Socrates and his fellow interlocutors employ. This extreme use of numbers is one of the reasons that scholars generally speak of the Laws as a more practical city-in-speech than the Republic. However, the numbers themselves have a fanciful quality to them, e.g. keeping the population at 5040 people because it is evenly divisible by all of the numbers between 1 and 10, as well as being divisible by 12 .
All of the quotations and references are pre-Socratic. None of the references come from sophists or poets who were a contemporary of Socrates (Zuckert) . The ideas that the Athenian Stranger espouses are distinctly pre-Socratic (Zuckert 54-57). For example, the god that the Αthenian Stranger proposes is not one of the traditional Olympians, but rather is a sort of amorphous, anonymous god in the style of the pre-Socratics, much more like the sun or the heavens than the personified Greek pantheon (Laws 715-716) . There are many more examples which Zuckert elaborates. I may, perhaps, go over them in more detail in a future blogpost.
The type of questioning in the Laws is distinctly not Socratic. The questions the Athenian Stranger and his interlocutors ask concern the best laws or the greatest justice, rather than considering the nature of law or justice (Zuckert 59). Furthermore, this questioning of the best laws tends to come from comparison and emendation of previously-existing laws rather than from the stance of "first principles" (i.e. deducing or hypothesizing from basic definitions to more specific principles).
- I mentioned some of the problems with using ancient sources in a recent blogpost. However, most of the sources are a few centuries later that Plato was writing so they should be taken with caution.
- He does express some small problems with this hypothesis, insofar as he says that the Cratylus is unfinished (Kraut 15). However, he sort of eventually pushes this concern aside.
- Some believe that the Athenian Stranger represents Plato himself in his old age (Zuckert 51-52).
- By "the Peloponnesian War," I mean the Second Peloponnesian War, which began approximately in 431. The First Peloponnesian War, which lasted intermittently from 460-445 and "was mostly fought by Athens against Sparta's allies" (timeline from my Greek history class).
- There are many more instances of the impracticalities of the Laws. Zuckert speaks about many of them in her opening chapter (Zuckert 51-148). I do not have the time or the expertise to discuss them at length here.
- I cannot actually vouch for any of this myself. I do not remember any quotations or concepts that were particular to the sophists or contemporary with Socrates, but my knowledge is not comprehensive enough to have been able to pinpoint every reference. Here, I am relying on Zuckert's assessment. However, the fact that he not only does not quote them, but does not mention the sophists, or even the word ἡ ῥητορική (Zuckert 85). Furthermore, according to Zuckert, claims that the power of speech alone cannot govern a society in terms of changing people's actions (Zuckert 90).
- Writing this I made reference to Zuckert 85-86.