The age-old, unanswerable question came to mind as I pondered two equally compelling objects on back-to-back days in San Francisco (8/13-14/16). The first was the “strandbeest” at the Exploratorium in an exhibit titled “The Dream Machines of Theo Jansen.” There were actually several on display, including one that was operational. Contraptions made largely of PVC pipe, these kinetic sculptures have been characterized as wind-walking artificial life forms by their maker, who has posited an evolutionary tree for them and enabled them to react to their environment. (If you are not familiar with the strandbeest, a visit to YouTube is better than any description I could provide.) They are, in their way, quite beautiful, and even moreso when in motion. They were not displayed in an art museum, however, but in a science museum, where the emphasis was on how they worked and how they were made, not how they looked.

In contrast, one gallery at SFMOMA was devoted to Melter 3-D by Takeshi Murata. A silver ball on a pedestal in the center of the room was lit by zoetrope lighting in a way that made the ball appear to be molten metal that was cascading down its surface (also available for viewing on YouTube). It, too, was beautiful and mesmerizing; but its appeal derived from a mechanical operation, a visual gimmick, if you will. Here, the emphasis was not on how it worked, but how it looked.

Science as art is neither new nor unusual. One thinks, immediately, of Leonardo da Vinci’s drawings of catapults and water flow, not to mention his backward handwriting, presented at the Minneapolis Institute of Arts last year. And for a gimmick-as-art, what about Arcimboldi’s portraits made of painted vegetables? What is architecture itself, if not a melding of art and science? Theo Jansen perhaps said it best: “The walls between art and engineering exist only in our minds.”

But they do exist, albeit in our minds, and I am no closer to identifying where they lie.