Firstly, I’d like to look at the two plays by considering the attack they each represent on form in drama. The Importance of Being Earnest was first performed in 1895. It appears to be so well-made, so highly-wrought, so earnest in fact in its observation of the conventions of comic drama, that its form could not disrupt audience expectations in the least. As one of Wilde’s most serious admirers, Jorge Luis Borges, has said: ‘His work is so harmonious that it may seem inevitable and even trite.’ (1) The musical metaphor is echoed in W. H. Auden’s remark that The Importance is the ‘...only pure verbal opera in English’. However, I would argue that by appearing so perfect and finished and well-rounded, the play actually mocks the conventions of its form, by drawing attention to them. It is rather like a building such as the Pompidou Centre in Paris, whose pipes and scaffolding, which could be hidden, and with most buildings usually are, are left exposed to remind us of the artificiality of the structure. This would make The Importance one of the first precursors of the postmodern concern with form as meaning, rather than transparent medium. The artifice declares itself, rather than covering up as part of real life.
Another postmodern characteristic of The Importance is its lack of differentiation between high culture and popular culture (definitions and the relative value of which are, of course, changing all the time, with the given historical context). As Katherine Worth has observed:

Besides melodrama, farce and burlesque were the reigning
forms in the nineteenth-century theatre. Wilde was very
much aware of the possibilities in these forms for modern
subversiveness: ‘Delightful work may be produced under
burlesque and farcical conditions, and in work of this kind
the artist in England is allowed very great freedom.’ (2)

In this way, Wilde made The Importance a farcical English version of the popular French boulevard melodrama. (3) In short, rather than see The Importance as a stereotypically well-structured comedy, it is perhaps just as valid to concur with Hesketh Pearson, who remarked that: ‘One cannot call it perfect of its kind, because there is no kind.’ Wilde’s feeling about comedy was part of his philosophy of opposites. ‘Never be afraid that by raising a laugh you destroy tragedy’, he wrote to Marie Prescott, the American actress who was to play Vera in The Nihilists, ‘...on the contrary, you intensify it.’ Tragedy has an optimistic side, paradoxically affirming the dignity of the human being, while comedy takes a more pessimistic view of things, entailing as it does a strong, offended sense of the ridiculousness of the human being, and the futility of human endeavour.
That brings us to Synge’s tragi-comedy, The Playboy of the Western World, first performed in 1907. Synge’s method of disrupting expectation through form works in the opposite way from Wilde’s. Wilde wrote a comedy that is so much a COMEDY that we are, as argued above, over-conscious of the form, and this subverted what was then the usual theatrical experience. Synge wrote a play which is not easily definable as either comedy or tragedy, and this is his method of subverting the then standard theatrical experience. The influence of Chekhov can be seen on both Wilde and Synge in this regard, both dramatists making their own use of different facets of Chekhov’s work. Chekhov’s way of orchestrating conversation can be seen in Wilde, while his disintegration of the categories of comedy and tragedy is obvious in Synge.
Next I want to turn to the use of language in both plays. It can be argued that the language in The Importance is standard English, and Synge himself wrote in the preface to The Playboy that: ‘I have used one or two words only that I have not heard among the country people of Ireland, or spoken in my own nursery before I could read the newspapers.’ (4) It is my contention, however, that the language of neither play is realistic, but is equally artificial in both. Much debate has raged among linguists as to the veracity or lack thereof of Synge’s Hiberno-English, and many quotations could be used to support a conclusion on either side. I have no wish to get into deep water in a field (to mix metaphors) in which I am not a specialist. But the argument of L. A. G. Strong encapsulates succinctly perhaps the most balanced view that can be taken of this problem:

The language of Synge’s plays is not the language of the
peasants, insomuch that no peasant talks consistently as
Synge’s characters talk; it is the language of the peasants,
in that it contains no word or phrase a peasant did not
actually use. (5)

It hardly matters whether the dialogue he used was an accurate and realistic transcription of actual dialects then in use. Its suitability and expressiveness are what recommend it. He claimed his language was faithful to peasant speech, but while it may have reflected reality it also supplanted it. The same is true of Wilde’s language. Standard English may be what all dialects of English are measured against, but it is itself an abstraction, existing only in the world of Platonic ideals (and BBC Radio 3 announcers’ received pronunciation accents, and Daily Telegraph columns, themselves pretty near partaking in the world of Platonic ideals also). No speaker of standard English speaks in such a consistently epigrammatic style as Wilde’s characters. Both Wilde and Synge, like many other great writers, invented their own language, and language in its turn is the hero of both these plays. One ruse they both use is that of absurd antithesis, the expectations aroused by the first part of a sentence, or a question, punctured and deflated by the second half of the sentence, or the reply. For example:

Algernon: I have a business appointment that I am anxious...to miss! (6)

Gwendolen: This suspense is terrible. I hope it will last. (Importance,
414)

Sara: And asking your pardon, is it you’s the man killed his father?
Christy: I am, god help me!
Sara: Then my thousand welcomes to you. (Playboy, 130)

Christy: We’re alike so.
Pegeen: I never killed my father. (Playboy, 122)

Pegeen: And to think it’s me is talking sweetly, Christy Mahon, and I
the Fright of seven townlands for my biting tongue. (Playboy, 156)

One point of difference between the two playwrights’ use of language is the possible limitations of Synge’s Hiberno-English. ‘It is not available,’ concluded T. S. Eliot, ‘except for plays set among that same people.’ (7) Wilde’s subversive discourse may be all the more subversive because it insinuates itself with a wider audience more easily. This is a point I will return to later.
So the language in both plays could be described as a fantastical exaggeration of a realistic starting-point, which is appropriate to storylines where wild improbabilities are accepted as matters of fact. It is these improbabilities that I now want to discuss.
Just as the individualistic use of language is all the more disconcerting to the audience because of its basis in reality, so the ghastly improbabilities are all the more disconcerting to us when we discover that we have so readily accepted them ourselves as reality during the play, taking our cue from the rest of the cast on stage. The conventions of melodramatic reactions to shocking events are deliberately undercut by an air of imperturbability. Thus each play, when looked at objectively, can be classed as high fantasy, but when experienced subjectively, seems quite normal. Both plays contain a double killing, and a double resurrection, and because the characters on stage have little hesitation in affirming them, so the audience affirms them too. Both plays privilege lies (or fictions) over any complacent truths, and Jack Worthing’s ‘Gwendolen, it is a terrible thing for a man to find out suddenly that all his life he has been speaking nothing but the truth’ (Importance, 418) finds its counterpart in Christy Mahon’s ‘...you’re after making a mighty man of me this day by the power of a lie...’ (Playboy, 162) Part of Shawn Keogh’s make-up as an object of derision is attributable to his ‘...middling faculties to coin a lie...’ (Playboy, 138) In one play a name is more important than the person it signifies; in the other the naming of a deed is more important than its actuality. This collapse of the distinction between fantasy and reality, lies and truth, this reversal of value systems, is a deeply subversive element in both plays.
A more obvious subversive quality in both plays is their sustained attack on the bourgeois conception of marriage, as the stuff of plays and life, and to a lesser extent, on organised religion. This starts on the first page of the text of The Importance, and is developed throughout. When Lane tells Algernon that: ‘I have often observed that in married households the champagne is rarely of a first-rate brand’, Algy replies: ‘Good heavens! Is marriage so demoralising as that?’ (Importance, 357) When Jack tells Algernon he has come up to town to propose to Gwendolen the riposte is: ‘I thought you had come up for pleasure?...I call that business.’ (Importance, 359) Algy’s quips continue:

Divorces are made in Heaven. (Importance, 359)

The amount of women in London who flirt with their own
husbands is perfectly scandalous. It looks so bad. It is
simply washing one’s clean linen in public. (Importance, 362)

...in married life three is company and two is none. (Importance, 363)

Of Lady Harbury, whose husband is recently deceased:

I hear her hair has turned quite gold from grief. (Importance, 364)

Gwendolen assures Jack that:

...men often propose for practice,... (Importance, 367)

and when Lady Bracknell objects to their marriage, says that:

...although she may prevent us from becoming man and
wife, and I may marry someone else, and marry often,
nothing that she can possibly do can alter my eternal
devotion to you. (Importance, 373)

We have Chasuble and Miss Prism’s discussion on the subject, and then later Cecily’s imagined engagement which she broke off, since: ‘It would hardly have been a really serious engagement if it hadn’t been broken off at least once.’ (Importance, 395) Most tellingly, there is Lady Bracknell’s marked change of tone on discovering that Cecily has a fortune of a hundred and thirty thousand pounds in the Funds, and her sudden desire to see Cecily and Algernon married as soon as possible. When she says:

Dear child, of course you know that Algernon has nothing
but his debts to depend upon. But I do not approve of
mercenary marriages. When I married Lord Bracknell I
had no fortune of any kind. But I never dreamed for a
moment of allowing that to stand in my way. (Importance, 409)

she reveals herself as a parvenu. Lady Bracknell also privileges the male interest in the marriage market over that of the female, an essential characteristic of the Victorian grande-dame. (Her attitude to her own daughter Gwendolen’s destiny is of course different, as shown by her reluctance to join her to a man ‘whose origin was a terminus’. (Importance, 408) But Gwendolen is in training to be her mother’s daughter: a woman who manipulates men in order that she may manipulate other women.) All of these examples show Wilde making fun of the trivial, conventionalised way love is treated, and the serious, mercenary way marriage is treated in the society he wrote about. They also demonstrate the elements of cover-up and exposure, the comedy demystifying marriage to show its ruthless economic basis.
Respectable marriage is also at the low end of the scale in Synge. He already made clear where his sympathies lay when he represented a young woman finding herself trapped in a loveless marriage in In the Shadow of the Glen. He attacks marriage in The Playboy through the figure of Shawn Keogh who, when Pegeen says: ‘you’re making mighty certain, Shawneen, that I’ll wed you now’, replies with: ‘Aren’t we after making a good bargain...’, again showing marriage as a financial arrangement devoid of love. (Playboy, 110) Marriage must be a sham, since it privileges the likes of Shawn over the likes of Christy, in spite of the fact that, as Widow Quin says: ‘It’s true all girls are fond of courage and do hate the like of you.’ (Playboy, 139) Shawn’s subservience to Fr Reilly gives us the anti-clerical dimension in the play. Christy has no qualms about staying with Pegeen while her father is at Kate Cassidy’s wake, but Shawn is: ‘...afeard of Fr. Reilly; and what at all would the Holy Father and the Cardinals of Rome be saying if they heard I did that like of that?’ (Playboy, 113) Pegeen’s attitude is clear: ‘Go on, then, to Fr. Reilly, and let him put you in the holy brotherhoods, and leave that lad to me.’ (Playboy, 120) An institution which favours Shawn over Christy must be corrupt. The anti-clericalism is more muted in Wilde, and directed at an Anglican clergyman, but when the unmarried Chasuble speaks of ‘A case of twins that occurred recently in one of the outlying cottages on you own estate. Poor Jenkins the carter, a most hard-working man’ (Importance, 382), he displays the narrow-mindedness and lack of understanding of the blinkered and pompous celibate. His values of thrift and hard work extend into the domain of procreation also.
It remains to examine to what extent the subversive elements in the plays outlined above represent a thoroughgoing policy in Wilde and Synge. The image of Wilde as apolitical dandy must by now surely be untenable, especially in the light of Richard Ellmann’s excellent critical biography. While in Louisville, during a lecture tour of America, he insisted, ‘Yes, I am a thorough republican. No other form of government is so favourable to the growth of art.’ (8) One has only to glance at ‘The Soul of Man Under Socialism’ (9) for proof, if any were needed, of his social conscience and commitment. The essay begins in a seemingly frivolous manner by declaring: ‘The chief advantage that would result from the establishment of Socialism is, undoubtedly, the fact that Socialism would relieve us from that sordid necessity of living for others which, in the present condition of things, presses so hardly upon almost everybody.’ Yet the argument is sound: altruism and charity are politically inexpedient, getting in the way of the only real solution to social ills, which would be ‘to try and reconstruct society on such a basis that poverty will be impossible.’ The essay continues in the same vein, opining ‘...charity creates a multitude of sins’, and ‘...the people who do the most harm are the people who try to do most good.’ Neither should we forget that Wilde’s first play was about a revolutionary movement.
The politics expressed in ‘The Soul of Man Under Socialism’ is evident everywhere in The Importance. Algernon is an anti-bourgeois figure: cucumbers could not be got ‘...even for ready money’ (Importance, 364), and he tears up his bills. Lady Bracknell, as a pillar of the establishment, is pleased that education in England ‘...produces no effect whatsoever’, since ‘If it did, it would prove a serious danger to the upper classes, and probably lead to acts of violence in Grosvenor Square’. (Importance, 368) She inquires did Jack’s father ‘...rise from the ranks of the aristocracy?’ (Importance, 369) Jack’s being a foundling displays ‘...a contempt for the ordinary decencies of family life that reminds one of the worst excesses of the French Revolution’ (Importance, 369), a revolution discussed in ‘The Soul of Man Under Socialism’ to illustrate the inevitability of change. On hearing of Bunbury’s demise she says:

Was he the victim of a revolutionary outrage? I was not
aware that Mr Bunbury was interested in social legislation.
If so, he is well punished for his morbidity. (Importance, 408)

Just as interested as Lady Bracknell in maintaining the present social order are Miss Prism and Chasuble. Prism tells Cecily to omit the chapter on the Fall of the Rupee in her Political Economy, since: ‘It is somewhat too sensational. Even these metallic problems have their melodramatic side.’ (Importance, 377), and Chasuble has delivered a sermon ‘...on behalf of the Society for the Prevention of Discontent Among the Upper Orders.’ (Importance, 381) The subversive quality of the form and language of the play represent a direct challenge to bourgeois practices of writing, in much the same way as the revolutionary force in Joyce’s practice of writing, by its refusal to conform to expectations, as Colin McCabe argues. (10) The strategy in the past of playing The Importance strictly for laughs is rather like that of pretending that Gulliver’s Travels (after a little bowdlerisation) is a children’s book: a bourgeois ploy to sterilise the radical thought and possible impact of the work.
D. E. S. Maxwell tells us that the phrase ‘...the idiocy of rural life’ was underlined by Synge in his copy of Marx’s Das Kapital, showing if nothing else that he had read the book. (11) In The Playboy Christy is the anti-bourgeois figure, offering Pegeen an alternative to the drabness of her role as a church-sanctioned object of exchange between her father and her prospective husband. The ultimate tragedy of the play is that Pegeen finally succumbs to bourgeois morality when she puts the rope over Christy’s head, and she colludes with Shawn Keogh by burning Christy with a lighted sod. Her bad faith, her lack of faith in the liberating power of imagination, and her recognition of ‘...a great gap between a gallous story and a dirty deed’ (Playboy, 165) result in her downfall, and are the reasons for her abandonment at the end. Words are not, and do not have to be, things, a notion which the villagers fail to recognise, because it frightens them. Again, form and language perform the same function here as in The Importance. Thomas Kilroy has written that Synge represents:

...a radical, anarchic spirit...one which invokes the kind of
aesthetic values that inform the best of modern writing. I
try to describe this sensibility as private, intensely preoccupied
with the nature of human freedom...radically subversive of the
established morality of middle class society. (12)

That is what I have tried to demonstrate here.
To conclude, I will briefly compare the overall achievement of one dramatist with the other. Just as Kilroy characterises Synge’s sensibility as private, it is possible to call Wilde’s public. In that oft-quoted remark to Andre Gide, Wilde said that he had put his genius into his life, and only his talent into his writings. Perhaps Synge put his genius into his writings, and that is why it was his play which gave offence while it was Wilde’s life which gave offence, and also why Synge’s life was so dull and Wilde’s so full of incident. However, this is not to denigrate The Importance as a safer play. Indeed, perhaps Wilde partakes more of the heroic than Synge, since it could be argued that his objectives were bolder, his risks greater, and consequently he had to be more careful and circumspect. He was acutely conscious of himself as an Irishman in England, and in a letter of 1893 wrote to Shaw: ‘England is the land of intellectual fog, but you have done much to clear the air: we are both Celtic, and I like to think we are friends.’ (13) The very gifts he used to charm the class which for a time accepted and feted him made him an object of suspicion: as Irishman, aesthete, homosexual, and above all, perhaps, as wit and artist, he was an outsider among the English. It is tempting to imagine Wilde as a Trojan horse in English society, and The Importance as a timebomb which, while not provoking riots on first performance, would go off much later. As the character Brigitte says, in Niall Quinn’s eponymously-titled short story from his criminally neglected collection Voyovic and Other Stories, during an argument in a London pub:

Violet, you sow, your kind taught even the Anglo-Irish to
despise you. You. Your kind. Even Wilde ridiculed your
sham of manners, Shaw scorned you - Behan threw your
own shit in your faces and you lapped it all up like demented
imbeciles. (14)

Synge limited himself to some extent, by using the Irish peasant backdrop and, as Eliot wrote, the Hiberno-English dialect. Nevertheless, the influence of both playwrights has been immense. There are echoes of Synge’s The Well of the Saints in Beckett’s Waiting for Godot. Riders to the Sea was worked into a version by Brecht called Senora Carrar’s Rifles, which he followed with Mother Courage where the debt is no less clear. Synge was also always a touchstone for Lorca. Wilde is echoed in the work of Joe Orton and Tom Stoppard, to name only two. While a postmodern reading of The Importance and a Marxist reading of The Playboy may seem quixotic in their redundancy, given what we now know about the fates and limitations of those aesthetic and socio-economic theories, perhaps these critical frameworks only became problematic and played-out when they were adopted by second-order, unoriginal minds. All innovators need followers to secure a reputation, but to what extent are they then responsible for the blind devotion or wilful distortions of their acolytes? Many ideas work much better in theory than in practice, and maybe it is only hegemonic ubiquity in the practical sphere which inspires a reaction against them in the theoretical one. At any rate, both The Importance and The Playboy can be read as existential quests of self-identity, a thoroughly modern, indeed timeless, preoccupation. The words ‘absurd’ and ‘nonsense’ recur frequently in The Importance, part of the mechanism of that timebomb which was to explode later in the theatre of the absurd. Meanwhile The Playboy heralded a century in which we were to hear more than a little about sons trying, and succeeding or failing, to kill their fathers.
So there are similarities and differences, and I am not about to decide which should be given the greater weight. In the Preface to The Tinker’s Wedding Synge wrote: ‘The drama, like the symphony, does not teach or prove anything.’ (15) Where have we heard this before?

No artist desires to prove anything. Even things that are
true can be proved. (16)

In both, art is seen as autonomous but as having social obligations. And art for art’s sake is the most socially subversive and artistically enabling credo and modus operandi of all.

BIBLIOGRAPHY
Borges, Jorge Luis. Other Inquisitions 1937-1952. London: Souvenir Press, 1973.
Ellmann, Richard. Oscar Wilde. London: Hamish Hamilton, 1987.
Harmon, Maurice, ed. J M Synge: the Centenary Papers 1971. Dublin: The Dolmen Press, 1971.
Kiberd, Declan. Inventing Ireland. London: Jonathan Cape, 1995.
McCabe, Colin. James Joyce and the Revolution of the Word. London: Macmillan, 1978.
Maxwell, D. E. S. A Critical History of Modern Irish Drama 1891-1980. Cambridge: Cambridge University Press, 1983.
Quinn, Niall. Voyovic and Other Stories. Dublin: Wolfhound, 1980.
Roche, Anthony. Contemporary Irish Drama. Dublin: Gill & Macmillan, 1994.
Strong, L. A. G. John Millington Synge. London: Allen and Unwin, 1941.
Synge, J. M. Plays, Poems and Prose. London: Dent and Sons, 1941.
Wilde, Oscar. The Picture of Dorian Grey. London: Dent and Sons, 1930.
Wilde, Oscar. The Importance of Being Earnest. London: Helicon, 1971.
Wilde, Oscar. The Complete Works of Oscar Wilde, Centenary Edition. London: Harper Collins, 1999.
Worth, Katherine. Oscar Wilde. London: Macmillian, 1983.

FOOTNOTES
1. Jorge Luis Borges, “About Oscar Wilde.” In Other Inquisitions 1937-1952
(London: Souvenir Press, 1973), 172.
2. Katharine Worth. Oscar Wilde (London: Macmillian Modern Dramatists), 20.
The inlaid quotation is from Wilde.
3. Another, much earlier instance of what I am suggesting here would be
Shakespeare’s use of the numerous revenge tragedies which were popular in
Elizabethan England in the writing of Hamlet.
4. John Millington Synge. The Playboy of the Western World, in Plays, Poems and
Prose (London: Everyman Classics), 107. All future references to this work will
be documented parenthetically, using the abbreviation Playboy.
5. L. A. G. Strong. John Millington Synge (London: Allen and Unwin, 1941), 81-
82.
6. Oscar Wilde. The Importance of Being Earnest, in Collins Complete Works of
Oscar Wilde, Centenary Edition (London: Harper Collins, 1999), 379. All future
references to this work will be documented parenthetically, using the abbreviation
Importance.
7. T. S. Eliot. On Poetry and Poets (London: Faber and Faber), 77.
8. Richard Ellmann. Oscar Wilde (London: Hamish Hamilton, 1987), 186; also
Declan Kiberd. Inventing Ireland (London: Jonathan Cape, 1995), 46.
9. Oscar Wilde. “The Soul of Man Under Socialism.” In The Complete Works of
Oscar Wilde, Centenary Edition (London: Harper Collins, 1999), 1174.
10. Colin McCabe. James Joyce and the Revolution of the Word (London:
Macmillan, 1978), e.g. 4: ‘Joyce’s texts, however, refuse the subject any dominant
position from which language could be tallied with experience. Ulysses and
Finnegans Wake are concerned not with representing experience through
language but with experiencing language through a destruction of representation.’;
and 160: ‘Joyce’s politics were largely determined by attitudes to sexuality.
Central to his commitment to socialism was his ferocious opposition to the
institution of marriage, bourgeois society’s sanctified disavowal of the reality
of desire’.
11. D. E. S. Maxwell. A Critical History of Modern Irish Drama, 1891-1980
(Cambridge: Cambridge University Press, 1984) 66.
12. Thomas Kilroy, from an article published in The Irish Times, 21/4/71, quoted in
Maxwell, 20.
13. Quoted in Worth, op. cit., 20.
14. Niall Quinn. Voyovic and Other Stories (Dublin: Wolfhound, 1980) 156.
15. Synge, op.cit., 33.
16. Oscar Wilde. The Preface to The Picture of Dorian Grey (London: Everyman
Classics, 1976), 1.