And here, I think, the first natural suggestion to make is that just as, when I talk of this inkstand, what I seem really to mean is the inkstand of which this is part of the surface, so that the inkstand is only known to me by description as the inkstand of which this material surface is part of the surface, so again when I talk of this material surface, what I really mean is the material surface to which this (presented object) has a certain relation, so that this surface is, in its turn, only known to me by description as the surface which has a certain relation to this presented object.