Few people advance so far into scientific study that they directly contend with knowledge that humans might not be equipped, or meant, to handle.

But Sir Isaac Newton — the subject of David MacGregor’s play “Gravity,” now having its world premiere at Chelsea’s Purple Rose Theatre — was very likely a member of this conflicted club.

“Gravity,” set in September of 1693, explores a mysterious, watershed time in Newton’s life. Six years following the publication of his groundbreaking book “Principia Mathematica,” Newton (Alex Leydenfrost) is holed up in his home laboratory, working 18-20 hours a day on a secret project.

Occasionally distracting him from his work are visits from his archrival Robert Hooke (Will Young); his philosopher friend John Locke (Jim Porterfield); and a mysterious, wealthy widow named Brilliana Cavendish (Michelle Mountain), who makes a point of reading and understanding Newton’s work.

Those who remember MacGregor’s previous plays at the Purple Rose — "The Late Great Henry Boyle” and “Vino Veritas” — won’t be surprised to learn that “Gravity”’s script is smart and, quite often, sharply funny. MacGregor writes great characters and dialogue, and it’s highly satisfying to learn while being entertained. (“Gravity” achieves this often during its nearly-2-hour run time.)

Even so, the show suffers a few minor missteps: the first act ends on a self-consciously clever punch-line instead of a dramatic turn that pulls us toward what's ahead; the passage of time within the narrative is a bit cloudy (we’re told Brilliana studied Newton's work for a fortnight or two, for instance, but I had no sense of that much time passing); and the members of a Greek-like chorus, while serving a key function in the show, play a larger role than is probably necessary (including a rendition of “Lavender’s Blue” by 2 performers in the first and final scenes).

Yet these are quibbles about a show that otherwise has an awful lot going for it. Director Guy Sanville has cast the show exceedingly well. Leydenfrost more than just looks the part of Newton; he makes the scientist’s vulnerabilities subtly show through his professional rigidity. Rhiannon Raglund earns laughs with her dry take on Newton’s tolerant housekeeper, Mrs. Grundy; and Porterfield does good work as the friend who must sometimes act as the voice of reason in the echo chamber of Newton’s lab and mind.

The play’s most crucial scene, however, belongs to Young, as his character tangles with Newton over the large-scale repercussions of his secret project. Hooke’s arguments gradually escalate into an impassioned boil, and thanks to Young’s masterful execution, the speech’s effect on Newton, and the audience, is gripping.

Daniel C. Walker has created a living space for Newton that looks worn and lived-in, but comfortable, with bookshelves lining the back wall of a sitting room and a lab occupying the downstage space. Prop designer Danna Segrest, meanwhile, deserves extra accolades for her meticulous work with Newton’s lab, filling it with instruments and equipment that bring the space, and the historical period, to life. Finally, Christianne Myers does excellent work with “Gravity”’s period costumes, making Hooke’s finery flashy and fussy, for instance, while Newton’s is appropriately austere.

More generally, Sanville creates some truly beautiful moments with “Gravity,” despite occasional slips into sentimentality; and MacGregor’s witty, erudite script provides loads to discuss and think about.

So while a play about a scientist may be a hard sell, my hope is that “Gravity” will, by word of mouth or otherwise, pull audiences in.

Jenn McKee is the entertainment digital journalist for AnnArbor.com. Reach her at jennmckee@annarbor.com or 734-623-2546, and follow her on Twitter @jennmckee.