The problem was first implied in Immanuel Kant 's discussion of a hand isolated in space, which would have no meaning as left or right by itself; Gardner posits that Kant would today explain his problem using the reversibility of objects through a higher dimension. A three-dimensional hand can be reversed in a mirror or a hypothetical fourth dimension. In more easily visualizable terms, an outline of a hand in Flatland could be flipped over; the meaning of left or right would not apply until a being missing a corresponding hand came along. Charles Howard Hinton expressed the essential problem in 1888, as did William James in his The Principles of Psychology (1890). Gardner follows the thread of several false leads on the road to the solution of the problem, such as the magnetic poles of astronomical bodies and the chirality of life molecules, which could be arbitrary based on how life locally originated.