'It is very difficult to solve.' Is this sentence above grammatically correct? Or does it have to be corrected as 'It is too difficult to solve.' ?
The idiomatic adjectival construction
has the same meaning as the construction
Not Verb Phrase
- It is too difficult to solve
means something like
(the particular negative construction is vague here because infinitives don't have tense or modality)
- It is so difficult that it can't/won't be solved
Too, in this construction, is a negative trigger, and can license Negative Polarity Items
like ever or take long, which can't occur outside a negative environment
- *He has ever gone there.
- *It takes long to do.
are ungrammatical without a negative, but
- He's too busy to ever go there. ( = He's so busy that he never goes/has never gone there)
- It's too simple to take long. ( = It's so simple that it won't/doesn't take long)
Both of these are correct, but mean different things.
It is very difficult to solve states that the problem is solvable, but with a high level of difficulty. Perhaps most people could not solve the problem.
It is too difficult to solve states that the problem is not solvable, even at a high level of difficulty.
The syntax for both of these sentences are equally correct, because too and very are both adverbs being used to modify the adjective difficult. Which sentence you want to use depends entirely upon what semantic modification you wish to convey.
Very is an adjective which is cognate with verify from the Latin adjective verus, which means "true". On this basis it would make sense for it to signify something along the lines of "truly", e.g., it is "truly difficult to solve." However, it may also be used as an adverb, and adverbs indicating truth are often used figuratively, as grammatical intensifiers:
Intensifiers are adverbs or adverbial phrases that strengthen the meaning of other expressions and show emphasis. Words that we commonly use as intensifiers include absolutely, completely, extremely, highly, rather, really, so, too, totally, utterly, very and at all[.]
Very is exemplified to be among the class of intensifiers, and I would usually expect very difficult to simply be a method of increasing the degree of difficulty to a certain amount, as shown in the following definition:
VER'Y, adverb As an adverb, or modifier of adjectives and adverbs, very denotes in a great degree, an eminent or high degree, but not generally the highest; as a very great mountain; a very bright sun; a very cold day; a very pernicious war; a very benevolent disposition; the river flows very rapidly.
The American Dictionary of the English Language (A.D.E.L.) by Noah Webster, s.v.very
In brief, very difficult means "more difficult than just difficult", and not necessarily "the most difficult" (much less "impossible").
Too, on the other hand, is an adverb that essentially means the same thing as overly, when it precedes the adjective it means to modify. It notes that the degree of difficulty is excessive: more than what is reasonable.
- Over; more than enough; noting excess; as, a thing is too long, too short, or too wide; too high; too many; too much.
His will too strong to bend, too proud to learn. [—Abraham Cowley]
A.D.E.L. s.v. Too
These concepts may seem rather similar, and they may indeed overlap in meaning. A person who finds something to be too difficult will almost always attest that it is also very difficult. The converse is not necessarily true, but it is perhaps more likely that a very difficult question will be found to be too difficult than a question which is just difficult.
However it is not necessary for the overlap to exist in all contexts. A question that is too difficult for a younger child to solve might not necessarily be very difficult for somebody with the accumulated knowledge and rational faculties of somebody who is older.
"We ask a child therefore, "What is your name?" If he replies only by his first name we insist on knowing his family name "Roger? And then? And what else? etc."
It happens sometimes that the child gives another name than the one by which he is enrolled. To explain these errors one must remember that there are many illegitimate children, and, what is more pitiable, the child's mother has had different husbands, and the name which the child bears in succeeding years is not always the same.
When a child is not able to give his family name one must not ask him for that of his mother, for this question is too difficult for a three year old child, and the reply "She's called Mama" cannot be taken as a bad answer for this age.
Publications of the Training School at Vineland, New Jersey, Department of Research, Issue 11 Here we are given an explanation regarding why a question that would be very simple for most people might be too difficult for a three year old child to satisfactorily answer. Whereas most adults would not consider this a very difficult question, and simply reply with our current legal surname, the three year old may have no concept of what that is, especially if the child has multiple potential answers to select.
I might call an examination too difficult if I do not believe that the students' curriculum prepared them to be able to answer it, even if the teacher can, or that the question is more advanced than they should be able to reasonably answer.
Teachers have slammed a Year 11 maths exam that has been deemed "far too difficult" for students and which reduced some to tears in the exam room.
However, teachers and students alike have rallied in their disappointment of the NZQA for putting out a test that was unfairly difficult and did not represent what students had been taught in the lead-up.
NZQA Slammed Over 'Far Too difficult' Maths Exam - Students Left in Tears from The New Zealand Herald
However, when designing a video game, I might name one of the difficulty settings very difficult with the full expectation that it should be eventually beatable by players who seek the sort of extra challenge enabling it gives them. This probably will not be too difficult for highly skilled players of the game, and may provide them with just the right degree of difficulty to prevent them from becoming bored.
In video gaming, "difficulty" often does not refer to how difficult a game is in general, but rather to a setting of the game, often chosen by the player in the menu or at the beginning of the game. Sometimes, the difficulty is set for the entirety of the game, sometimes it can be changed during the game. In many video games, difficulty modes run on a general scale of:
- Very easy (sometimes known as "beginner", "novice", "basic", etc.)
- Normal (sometimes known as "medium", "intermediate", etc.)
- Very hard (sometimes known as "hardcore", "nightmare", "extreme", "impossible", etc.)
I would mention a particular game by name, but unfortunately the naming variations make it difficult for me to think of one with a plainly named "very difficult" setting. I think I have seen some before, though.
Without further context and information, I cannot tell you which one you should use, but hopefully, with this information, you should be able to compare the words and figure which one is better suited to your context for yourself.