After walking twice around political science professor Edward Tufte’s GRD ’68 show at the Aldrich Contemporary Art Museum in Ridgefield Conn., I could not help but ask myself this simple question: how can modern sculptors continue to make challenging art?

It’s not that Tufte’s show is bad — as a first attempt at large-scale public presentation of his sculptures, it’s not. But he is clearly struggling to escape from the heavy burdens of conceptual originality that all modern sculptors face.

The first piece the viewer sees after entering the garden outside the museum, where most of the larger sculptures are situated, is “Skewed Machine,” literally a skewed bulldozer on a cement pedestal. Visually, the piece is interesting in its scale and obvious heaviness, but it does not say anything that has not already been said by large, physically intimidating sculpture.

The main theme of the show that all of Tufte’s sculptures grapple with — “3-D relationships within the piece and with its airspace,” as Tufte wrote in his accompanying essay “Seeing Around” — is age-old, and has often been revisited, most recently by artists like Fred Sandback or even Franz West, whose sculptures are currently on display at the Yale University Art Gallery.

The problem is not that Sandback or West came first, but that Tufte’s art challenges neither their nor others’ understandings of the interaction between space and object. Successful sculpture, and successful art in general, should not try to interpret similarly what has come before but should reexamine the motives behind existing interpretations.

While the exhibition may not be generating any new ideas, as an exploration or catalogue of previous attempts to understand the relationship between sculpture and space, it is a success. Tufte is exploring previously discovered territory, but with the help of his essay “Seeing Around,” he makes some of the less obvious interactions between space and shape more understandable. Tufte clarifies for the viewer the changing relationships between shadow and sculpture, between position and perception, but his art is explanatory, not redefining.

He grasps well the art that has come before his own, and it is because of his willingness to admit major influences that his objective redeems itself. He may not be doing anything new, but he also is not claiming to. And while this takes away from the art itself, it adds to the authenticity of his exploration. In one respect, Tufte may be quite right: everything can be revisited at some point.

At the end of his essay, Tufte tries to preempt criticism of his work.

“Abstract sculptors make objects that generate unique optical experiences … [The viewer should] concentrate initially on the unique experience,” Tufte wrote.

He raises a good point: to what degree do we ever judge art based on what we feel, and to what degree does the need to categorize and simplify take precedent?

As valid as this question is, it may be leaving out an important second dimension. While any unique experience is valuable, all visual experiences are probably unique to some degree, so there must be more than this one criterion for judging art. If the first is visual, the second is internal. We see and react, and then we think and compare. Both steps are important, both determine how successful a piece of art actually is, and while arguably evocative in the first respect, Tufte’s show ultimately fails to pass the second step of judgment.