Though in its time it was accused of an almost ostentatious luminosity, today, in the protruding storefront gallery of Sprüth Magers, Joseph Kosuth’s neon oeuvre appears almost quaint. This is, after all, the dead end of Mayfair’s most hedonistic thoroughfare, home to Hix, Louboutin, and Zwirner. So Kosuth’s “merchandise,” as it’s displayed, is up against some considerable flash.

But appearances are only a means to an end in his work. A pioneer of conceptual light art who preceded even Bruce Nauman and Keith Sonnier, Kosuth is a front for complex ideas steeped in philosophical and psychological scholarship. And though his textual pieces directly confront the more ambiguous conceptual work out there (neon signage is just the right medium for this), it doesn’t say all that needs to be said. Kosuth’s seamless, fluid lines may make it look as if everything is orderly and precise, but that’s a master of deception at work.

I won’t call this a comprehensive retrospective—Sprüth Magers is a bijou gallery and Kosuth, looking rather robust as if surrounded by admirers at the bar throughout the recent opening, is certainly not done yet. “Amnesia: Various, Luminous, Fixed.” [sic] features some of the artist’s finest and most debated works, from his earliest neons in 1965 through to 2011.

That main gallery, in full view far down Dover Street, is home to Kosuth’s two-dimensional representations of third- and even fourth-dimensional problems, seemingly worked out in real time, like the blackboard in A Beautiful Mind. The six-sided volumes are handsome, mathematical trompe l’oeils. Formulas and annotated diagrams take shape in intense primary color. There’s a selection from Kosuth’s tribute to Donald Judd, the early neon “Five Fives (to Donald Judd),” [orange], (1965), in which five rows of five numbers each are spelled out in words, asking the viewer to consider the numerical value against its formal expression.

The artist also pays homage to Samuel Beckett with his “Texts for Nothing (Waiting for-)#7 (2011). “Scattered ruins same grey as the sand ash grey true refuge,” it says, a code of randomly ordered words from Beckett’s 1970 story-puzzle Lessness. The writer often spoke of the impossibility of deriving meaning from words—and used silence, instead, as a way of saying the unsayable. Kosuth, in appropriating Beckett’s text and isolating only a few words, allows them to be ascribed with fresh meaning.

“Amnesia” is an apt title here at Sprüth Magers. Who will remember having read Lessness, let alone any of Beckett, save for a few choice lines from Godot? It’s a bit unfair, really. Kosuth lives with these ideas for months and years, forming them first in his head, then in his medium, and then on the wall. We have but a few moments before our thoughts are interrupted by everyday gallery chatter.

Indeed, who among us can remember the subtleties of Ulysses from their high school lit class? Yet here it is in buzzing (literally, figuratively) white neon. For “Ulysses, 18 Titles and Hours” (1998), Kosuth has appropriated the 18 episodes in the life of Leopold Bloom and assigned each the time of day in which it took place: “8am. Telemachia” at ceiling level; “11am. Hades” above the floor. The meaning, like the original text, is intentionally ambiguous, its language impenetrable. The act of reading, craning your head 360 degrees to see all the titles, becomes part of the experience.

Kosuth believes the artist’s role in society is as a pot-stirrer, raising questions that have no definitive answer. He loves leaving an untied thread for the viewer to pick up and mend. On opening night, I think he enjoyed watching us all fumble with his loose ends, waiting patiently and knowing that, unlike Godot, we’d get there, eventually.