The shifting place of 'secondary qualities' in the history of philosophy[80] is another excellent proof of the fact that 'inner' and 'outer' are not coefficients with which experiences come to us aboriginally stamped, but are rather results of a later classification performed by us for particular needs. The common-sense stage of thought is a perfectly definite practical halting-place, the place where we ourselves can proceed to act unhesitatingly. On this stage of thought things act on each other as well as on us by means of their secondary qualities. Sound, as such, goes through the air and can be intercepted. The heat of the fire passes over, as such, into the water which it sets a-boiling. It is the very light of the arc-lamp which displaces the darkness of the midnight street, etc. By engendering and translocating just these qualities, actively efficacious as they seem to be, we ourselves succeed in altering nature so as to suit us; and until more purely intellectual, as distinguished from practical, needs had arisen, no one ever thought of calling these qualities subjective. When, however, Galileo, Descartes, and others found it best for philosophic purposes to class sound, heat, and light along with pain and pleasure as purely mental phenomena, they could do so with impunity.[81] Even the primary qualities are undergoing the same fate. Hardness and softness are effects on us of atomic interactions, and the atoms themselves are neither hard nor soft, nor solid nor liquid. Size and shape are deemed subjective by Kantians; time itself is subjective according to many philosophers;[82] and even the activity and causal efficacy which lingered in physics long after secondary qualities were banished are now treated as illusory projections outwards of phenomena of our own consciousness. There are no activities or effects in nature, for the most intellectual contemporary school of physical speculation. Nature exhibits only _changes_, which habitually coincide with one another so that their habits are describable in simple 'laws.'[83] There is no original spirituality or materiality of being, intuitively discerned, then; but only a translocation of experiences from one world to another; a grouping of them with one set or another of associates for definitely practical or intellectual ends. I will say nothing here of the persistent ambiguity of _relations_. They are undeniable parts of pure experience; yet, while common sense and what I call radical empiricism stand for their being objective, both rationalism and the usual empiricism claim that they are exclusively the 'work of the mind'--the finite mind or the absolute mind, as the case may be. * * * * * Turn now to those affective phenomena which more directly concern us.