The word _meaning_ is a familiar everyday term; the words _conception_, _notion_, are both popular and technical terms. Strictly speaking, they involve, however, nothing new; any meaning sufficiently individualized to be directly grasped and readily used, and thus fixed by a word, is a conception or notion. Linguistically, every common noun is the carrier of a meaning, while proper nouns and common nouns with the word _this_ or _that_ prefixed, refer to the things in which the meanings are exemplified. That thinking both employs and expands notions, conceptions, is then simply saying that in inference and judgment we use meanings, and that this use also corrects and widens them. [Sidenote: which is standardized] Various persons talk about an object not physically present, and yet all get the same material of belief. The same person in different moments often refers to the same object or kind of objects. The sense experience, the physical conditions, the psychological conditions, vary, but the same meaning is conserved. If pounds arbitrarily changed their weight, and foot rules their length, while we were using them, obviously we could not weigh nor measure. This would be our intellectual position if meanings could not be maintained with a certain stability and constancy through a variety of physical and personal changes. [Sidenote: By it we identify the unknown] [Sidenote: and supplement the sensibly present] [Sidenote: and also systematize things] To insist upon the fundamental importance of conceptions would, accordingly, only repeat what has been said. We shall merely summarize, saying that conceptions, or standard meanings, are instruments (_i_) of identification, (_ii_) of supplementation, and (_iii_) of placing in a system. Suppose a little speck of light hitherto unseen is detected in the heavens. Unless there is a store of meanings to fall back upon as tools of inquiry and reasoning, that speck of light will remain just what it is to the senses--a mere speck of light. For all that it leads to, it might as well be a mere irritation of the optic nerve. Given the stock of meanings acquired in prior experience, this speck of light is mentally attacked by means of appropriate concepts. Does it indicate asteroid, or comet, or a new-forming sun, or a nebula resulting from some cosmic collision or disintegration? Each of these conceptions has its own specific and differentiating characters, which are then sought for by minute and persistent inquiry. As a result, then, the speck is identified, we will say, as a comet. Through a standard meaning, it gets identity and stability of character. Supplementation then takes place. All the known qualities of comets are read into this particular thing, even though they have not been as yet observed. All that the astronomers of the past have learned about the paths and structure of comets becomes available capital with which to interpret the speck of light. Finally,