 The “concept of a transcendental object” might be fruitfully thought of as “the transcendental concept of an object”: the concept of “object” that makes experience possible. Our mind’s synthesis of representations into experience of objects is guided and made possible by the idea that there is a way objects are that must be tracked by our representations of them. This wholly abstract concept of “a way things are” is the concept of the transcendental object = X, the indeterminate concept of the “target” of our representational activity. Consequently, the concept of the transcendental object must be distinct from the concept of “things in themselves” or “negative noumena”. The concept of things in themselves is the concept of the (unknowable by us) objects (or aspects of objects) that appear to us the 3D world of space and time. They are the grounds of phenomena, while the transcendental object is the very abstract idea of those objects in space and time as the targets of our cognitive activity.