+0
Historians then came to believe that their task
was not so much to paint a picture as to solve a
problem; to explain or illustrate the successive
phases of national growth, prosperity, and
adversity.

...

To specify what was brought just before, as highlighted here:

"Historians then came to believe that their task
was not so much to paint a picture(1) as to solve a
problem(2); to explain(2) or illustrate(1) the successive
phases of national growth, prosperity, and
adversity."?
+0
.
The semicolon is in error-- a colon will fix the punctuation, but the sentence needs a rewrite, since it is not clear that the nonfinite clause after the colon represents a 'problem'.

Historians then came to believe that their task was not so much to paint a picture as to solve a problem: to explain or illustrate the successive phases of national growth, prosperity, and adversity.

Ah, I now see your exegesis. I now suggest:

Historians then came to believe that their task was not so much to paint a picture as to solve a problem or to explain or illustrate the successive phases of national growth, prosperity, and adversity.

.
Comments  
Teachers: We supply a list of EFL job vacancies
AnonymousHistorians then came to believe that their task
was not so much to paint a picture as to solve a
problem; to explain or illustrate the successive
phases of national growth, prosperity, and
adversity.

Fowler said that the semi-colon was "a discontinuity of grammatical construction greater than that indicated by a comma but less than that indicated by a full stop". They are often used to indicate the end of a sentence, or a significant part of a sentence, where what follows is quite closely linked to what has just been said. The colon suggests a closer link between what is about to be said, and what has just been said, i.e. to introduce a list or, perhaps, a series of clauses in apposition.

What we have here is a problem, and what follows the semi-colon is a statement of what the problem is. Now Fowler's conditions seem to me to be met here, and one might, in my view, be quite correct to use a semi-colon. Use the colon and you, to my ear, are making a greater break and blowing a few more trumpets about the nature of the problem. It's a matter of which you want to do.

Fowler died in 1933 and a lot of people think that punctuation practice has evolved greatly since then.

[...]

Mister Micawber.
The semicolon is in error-- a colon will fix the punctuation, but the sentence needs a rewrite, since it is not clear that the nonfinite clause after the colon represents a 'problem'.

Historians then came to believe that their task was not so much to paint a picture as to solve a problem: to explain or illustrate the successive phases of national growth, prosperity, and adversity.

Ah, I now see your exegesis. I now suggest:

Historians then came to believe that their task was not so much to paint a picture as to solve a problem or to explain or illustrate the successive phases of national growth, prosperity, and adversity.

.

Wait, I don't understand what you are trying to say.

Am I right?

Here's the full extract:

2 Historians then came to believe that their task
was not so much to paint a picture as to solve a
problem; to explain or illustrate the successive
phases of national growth, prosperity, and
adversity.

2 The meaning of the topic sentence made
clearer; the new conception of history defined.
Does "to explain or illustrate the successive phases of national growth, prosperity, and adversity." explain the previous objects or describe the true task of Historians?
Students: Are you brave enough to let our tutors analyse your pronunciation?
.
A semicolon must be preceded and succeeded by an independent clause. Therefore, it is wrong in the sentence. I have offered you two alternatives.
.