However is a useful and forceful word that is weakened by misuse and overuse. Although there is much discussion in usage guides about where to position it in a sentence, there are no absolute rules about this, and the word can be debased even when properly positioned. Some discussion may help clarify how to use it well. This is a long post, so I’ve divided it into general sections.
However has two key functions:
(1) As a pure adverb that means to whatever extent or in whatever way:
However far you go, you’ll always remember home.
However this problem arose, we can’t deny its importance.
(2) As a conjunctive adverb that means nevertheless and shows contrast with what went before:
We were now utterly lost. However, we decided to persevere.
The study was deemed a success. The results, however, had yet to be published.
However’s function as a conjunctive adverb is what chiefly concerns me here, since it often replaces coordinating or subordinating conjunctions like but, yet, still, though or although, yet only occasionally improves on them. Each of these terms has its own adversative nuances, so you should let context guide your selection. For instance, the sample sentence above might be better written as:
We were now utterly lost, but we decided to persevere.
Although we were now utterly lost, we decided to persevere.
Where possible, writers should take time to choose whichever terms in whatever order best communicate their essential ideas. Unfortunately they often don’t or can’t, and however’s popularity has soared.
To show what I mean, I’ve re-written the first paragraph with three extra howevers, more or less as the word is commonly used. Under the guise of mild parody lurks a dubious plan to make you hypersensitive to however through overexposure, and hence less inclined to use it too casually:
However is a useful and forceful word. However, it is weakened by misuse and overuse. There is much discussion in usage guides about where to position it in a sentence; however, there are no absolute rules about this, and the word can be debased even when properly positioned. Some discussion, however, may help clarify how to use it with more care and diligence…
Some writers rely on however in this fashion – to express almost any distinction or contrast – when in many cases it need not be used at all, and should at least be weighed against its alternatives. Writing one however after another turns text into a kind of rhetorical pinball, and readers can easily lose track of the text’s essential meaning.
However should not be avoided whenever possible, but unless you use it with good judgement and restraint, you run the risk of using it superfluously, inappropriately, or both.
But in particular seems to have lost out. It is short, plain, emphatic and versatile, yet many writers shun it, apparently either neglecting to consider it or sensing that they will be taken more seriously if they use however as much as possible. But however doesn’t automatically confer authority on one’s writing, and indeed can have the opposite effect unless used prudently.
When you use however as a conjunctive adverb, be cautious about placing it at the end of a sentence or clause – especially a long one – where it delays the signal of contrast and can take the oomph out of whatever precedes it. Placed at the beginning it can also reduce emphasis, by making your reader wait for the subject, however momentarily.
Despite what Strunk wrote in The Elements of Style, this is not an absolute proscription: there are occasions when the start of a sentence is the best place for however. When this positioning becomes habitual, however, the word loses what effect and grace it might otherwise offer.
A general guideline: however works best when used sparingly, and when positioned just after whatever requires emphasis:
Most of the people at the parade were generally enthusiastic. Some, however, were disappointed by how quickly it finished.
The children tiptoed towards the swan. When it suddenly flapped its wings, however, the kids retreated.
Misuse and punctuation
Using however to open a clause, without any punctuation, turns however into a full conjunction like but, which it isn’t. Some untrained writers and news media habitually misuse the word thus:
However the most surprising thing is…
The teams were level at half time, however within ten minutes of the second half…
This practice also confuses the conjunctive adverb however with the pure adverb however, since the latter never takes a following comma. One authority describes this usage as an illiteracy; I wouldn’t go that far, but it certainly clouds a couple of useful distinctions. It may be partly caused by mimicry: when people read however in print media, overused as it is, they easily overlook the surrounding punctuation – if there is any. In spoken reports, meanwhile, the pauses signalled by punctuation are often negligible or missing altogether.
However is often implicated in comma splices, which are also mentioned in the final bullet point of my post on semicolons; that post has further information on punctuating around however when it joins two independent clauses (generally a preceding semicolon and a following comma). Enclosed by commas it underlines what precedes it, often with contrast. Without either it points to the contrast without emphasis; this lets you avoid unnecessary punctuation where no ambiguity is likely to arise.
A mistake to watch out for is writing however when you mean how ever. In this phrase, ever either intensifies how (in dialogue or colloquial usage), or has its full meaning of under any circumstances or at any time. In both cases it requires separation, sometimes with intervening words:
How ever did you manage to reach that summit? (Or How did you ever manage…, not However did you manage…)
Daily Google users wonder how they ever survived without it. (Not however they survived…)
There’s more, but that will do for now.