_2. Matter in Itself:_ "What matter is, in itself and by itself, is quite hopeless of answer and concerns only metaphysicians. The "Ding an sich" * * * is forever outside the province of science. If all men stopped to quarrel over the inner inwardness of things, progress, of course, would cease. Science is naive; she takes things as they come, and rests content with some such practical definition as will serve to differentiate matter from all other forms of non-matter. This may be done strictly provisionally in this place, by defining matter as that which occupies space and possesses weight. Using these two properties it is readily possible to sift out matter from all the heterogeneous phenomena that present themselves to the senses, and that, in this place, is what we want. Thus, wood, water, copper, oil and air are forms of matter for they evidently possess weight and fill space. But light, heat, electricity and magnetism we cannot consider to fill so many quarts or weigh so many pounds. [Light, heat, electricity--are properties of matter.] They are, therefore, forms of non-matter. In like manner, things such as grace, mercy, justice and truth, while they are existing entities as much as matter, are unquestionably non-matter" [Grace, mercy, etc., are qualities of spirit, which itself is doubtless matter, but of finer quality than that which is recognized by the senses.] ("The New Knowledge," R. K. Duncan, p. 2.) _3. Indestructibility of Matter:_ "The gradual accumulation of experiences, has tended slowly to reverse this conviction [i. e. that matter may be annihilated]; until now, the doctrine that matter is indestructible has become a commonplace. All the apparent proofs that something can come out of nothing, a wider knowledge has one by one cancelled. The comet that is suddenly discovered in the heavens and nightly waxes larger, is proved not to be a newly-created body, but a body that was until lately beyond the range of vision. The cloud which in the course of a few minutes forms in the sky, consists not of substance that has just begun to be, but of substance that previously existed in a more diffused and transparent form. And similarly with a crystal or precipitate in relation to the fluid depositing it. Conversely, the seeming annihilations of matter turn out, on close observation, to be only changes of state. It is found that the evaporated water, though it has become invisible, may be brought by condensation to its original shape. The discharged fowling-piece gives evidence that though the gunpowder has disappeared, there have appeared in place of it certain gases, which in assuming a larger volume, have caused the explosion." "First Principles," (Herbert Spencer), p. 177, Appleton Edition, 1896.