Regarding extension as quality of mode of substance, and not as substance itself, it appears absurd to argue that the quality exists otherwise than as quality of mode. The whole of the propositions following the first are so built upon it, that if it fails they are baseless. The second proposition is, that infinity of extension is necessarily indivisible. In dealing with this proposition, Mr. Gillespie talks of the _parts_ of infinity of extension, and winds up by saying that he means parts in the sense of partial consideration only. Now not only is it denied that you can have any idea of infinity of extension, but it is also denied that infinity can be the subject of partial consideration. Mr. Gillespie's whole proof of this proposition is intended to affirm that the parts of infinity of extension are necessarily indivisible from each other. I have already denied the possibility of conceiving infinity in parts; and, indeed, if it were possible to conceive infinity in parts, then that infinity could not be indivisible, for Mr. Gillespie says that, by indivisible, he means indivisible, either really or mentally. Now each part of anything conceived is, in the act of conceiving, mentally separated from, either other parts of, or from the remainder of, the whole of which it is part. It is clearly impossible to have a partial consideration of infinity, because the part considered must be mentally distinguished from the unconsidered remainder, and, in that case, you have, in thought, the part considered finite, and the residue certainly limited, at least, by the extent of the part under consideration. If any of the foregoing objections are well-founded, they are fatal to Mr. Gillespie's argument.