reat them as rigorously mental or as
rigorously physical facts. So they remain equivocal; and, as the world
goes, their equivocality is one of their great conveniences.

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
definit