Christopher Gray has plenty of praise for NT boss Nicholas Hytner’s final gig

Tom Stoppard tackles weighty matters in his new play, The Hard Problem, and they might have been weightier still but for his fear of an intellectual deficiency on the part of his audience.

In truth, Sir Tom’s much publicised admission to having dumbed down the work applies to specific cultural allus-ions in it, which went uncomprehended by people at previews, rather than to the broader themes it covers.

These, in a nutshell, centre on the mystery of consciousness. The “hard problem,” as Stoppard puts it in a programme note, is how to explain the phenomenon that we have subjective first-person experiences. Do these derive simply from the brain or from another entity; call it the mind or soul?

Hilary (Olivia Vinall), the engaging heroine of the play — Stoppard’s first in nine years — inclines to the second view. She even prays to God, to the surprise and dismay of other scientific minds around her at the Krohl Institute for Brain Science.

We first meet her as a psychology student at Loughborough University, where she is being coached — in between bouts of athletic love-making — for a job interview at this august establishment. Her mentor is her on-off boyfriend (if the pun can be forgiven). Spike (Damien Molony), who is a mighty clever clogs and proud to be so.

Something in his teaching must be right, for Hilary goes on to win the approval of the good-natured department boss Leo (Jonathan Coy) and gain employment.

This comes as a significant shock to her cocksure rival candidate, Amal (Parth Thakerar), who clearly considers the job to be his.

No matter: he is to find employment perhaps better suited to his hard-nosed talents, working for the hedge-fund whose boss is the institute’s philanthropic founder, tough-cookie billionaire Jerry Krohl (Anthony Calf).

The action throughout the 100-minute drama, played without interval, focuses principally on Hilary, who is strongly and sympathetically portrayed by Ms Vinall. Attention is divided between her workplace – where a collaboration with gifted mathematician Bo (Vera Chok) comes to have great importance – and her private life, much affected by her anxiety over the child she bore at 15 and gave up for adoption.

Its heady intellectual content includ-es much to do with human motivation; whether we do good for its own sake, or for purely egotistical reasons. There is talk, too, concerning coincidence, thereby laying the groundwork for a whopping example of it soon to follow.

Nicholas Hytner, in his last gig as the NT boss, directs at a cracking pace, while Bob Crowley supplies a set suited to the action, with its tangle of overhead lights suggestive of the brain and its electrical activity.

Entertaining as well as educative, the play should not be missed.

The Hard Problem
National Theatre, Dorfman Theatre
Until May 27
Tickets: 020 7452 3000
Also live screening at local cinemas on April 16