A bare six or seven years ago, when Brad Mehldau began to make his presence felt on his first recordings, there was already something indefinable about his playing. Call it what you like, but it was redolent of stage presence, that elusive but unmistakeable quality that some great actors have. And though it marked him out as one to watch, there was little about those early albums to suggest the astonishing rate of development that has emerged in recent years.
On several of those early recordings, made in the first half of this decade under the leadership of such as guitarist Peter Bernstein and tenor saxophonist Grant Stewart for the Dutch label, Criss Cross, the jazz style was basically bop, swinging and straight-ahead. Mehldau took to it as to the manner born, bringing a sparklingly buoyant, vibrantly alive touch that recalled the late Wynton Kelly, the pianist in the great Miles Davis rhythm section that also included bassist Paul Chambers and drummer Jimmy Cobb.
While it may be no coincidence that one of Mehldau's early teachers at Manhattan's highly respected New School For Social Research was Cobb - and both Mehldau and fellow student Bernstein played in Cobb's quartet for a while - Kelly would still have been an unusual influence for one of today's young pianists. In no sense an innovator, he was firmly within the bop idiom and never showed any sign of wishing to explore beyond it - but he did have a marvellous ear and a joyous, song-like, exuberantly visceral character to his playing.
He also had something else. As another pianist, the late, great Bill Evans, pointed out, despite sounding natural and unforced, Kelly's solos were also acutely organised - and he had the ability to do it, spur of the moment, time and time again. In other words, he had somehow managed to strike a balance between feeling and form, the emotional and the cerebral - much as his boss, Miles Davis, had done repeatedly in different ways throughout his own long career.
And that's something that has characterised Mehldau's development as an artist, if his recordings are any guide - a striving to reach a balance between a passion that must be expressed and the building blocks of technique, form and improvisational structures that are used to do it. And Kelly, in his different way, epitomised that crucial "balance."
But Miles Davis's pianist was only one influence on Mehldau. Others in jazz include Oscar Peterson, Bill Evans, McCoy Tyner, Herbie Hancock and Keith Jarrett, along with Davis and John Coltrane - a hugely diverse bunch embracing both sides of the mind-soul duality. Equally central to Mehldau's interests and development, however, is classical music. He has made it repeatedly clear that other influences include Schubert, Brahms, Schumann, Beethoven and Chopin - an equally diverse bunch spread across the same mental and emotional spectrum.
And they're not simply borrowed finery to give his music some gilt-by-association. Classically trained, he has certainly absorbed some of their harmonic language. He also loves the device of taking small, or relatively small, thematic materials to construct larger edifices of musical thought and to explore the resultant possibilities, as he has done on his latest album - and first solo piano release - Elegiac Cycle (Warner Bros), and as he is likely to show in his solo performance this coming Monday night.
But the point about all these so-called "influences" is that Mehldau's recordings under his own name - and the performances of his that I've heard - increasingly reveal that these "influences" were seeds sown in the fertile ground of his own personality. In other words, that early sense of a great actor's stage presence suggests that these were never things to be copied, but rather to be engaged with in a kind of spiritual dialogue. And Mehldau is one of those fortunate few to be gifted with the innate wherewithal to sustain and develop that dialogue, a kind of constant awareness of the past from someone who knows that, ultimately, what he's doing when he plays or composes is just his own take on the raw materials at his disposal. The knowledge also comes without losing sight of the sheer breadth and complexity of emotion that must breathe life into it. Even his liner notes - on Elegiac Cycle and the earlier live Village Vanguard album, The Art Of The Trio, Volume Two - grasp, in their idiosyncratic but nevertheless rigorous way, this essential truth.
Idiosyncratic? What jazz musician - or what musician of any idiom - has ever, in liner notes, invoked Apollo, Orpheus, Plato and Socrates, writers like Oscar Wilde, Thomas Mann and Bertolt Brecht, or philosophers such as Rousseau, Locke and Diderot? Or conducted a discussion on irony between two "sides" of his artistic persona, or discoursed on art, life, memory and romantic freedom, too?
It would be easy to dismiss all this as the pretentious guff of an earnest young man - Mehldau, after all, is only 29 this month - except that it addresses clearly-perceived characteristics of art in general and music in particular with a consistent and logical concern for what the performer has to deal with. Also it's often expressed with a well-developed sense of fun and (that word again) irony.
Finally, though, there is always the music, which is anything but earnest and pretentious. In music, he wrote in the sleeve note for The Art Of The Trio, Volume Two, "you can have your cake and eat it, too. When else do you get to have an experience that is at once intellectual and sensual? In the language of music, high rhetoric and primordial instinct come together within a single expression - they're somehow one."
Where this gifted young pianist will take that language in the future is anybody's guess - including, perhaps, his own. But it will be an interesting trip and it won't lack passion, a probing mind or surprises - rather like what may be in store on Monday night.
Brad Mehldau plays in Vicar Street on Monday night