It is, then, because some substantial loss or gain does truly take place in the changing phenomena of the bodies immediately around us, to which we are accustomed to pay our principal attention, that we learn to regard a change of state in matter as significant of loss of identity, and to feel, therefore, some hesitation in admitting the mental changes of state to be consistent with absolute sameness of substance. Had our observation of the _material_ phenomena been different, there would have been a corresponding difference in our view of the changes of the phenomena of the mind. If, for example, instead of previously gaining or losing caloric,--as in the constitution of things of which we have our present experience,--the particles of the water had suddenly assumed the state of _vapour_ on the sounding of a trumpet at a distance, and the state of _ice_ immediately on the rising of the sun,---in short, if the different changes of state in bodies, by which their physical character for the time seems, in many cases, to be wholly altered, had occurred without any apparent loss or gain of substance, we should then no longer have found the same difficulty in admitting the changes of state in mind as consistent with its identity; and the sentient substance, which previously existed in a different state, might then, on the sounding of a trumpet, have been conceived by us to begin to exist, in the state which constitutes that particular sensation of hearing, or, on the rising of the sun, to exist in that different state which constitutes the sun's change of colour as readily as the material substance, previously existing in the form of water, to begin at the same moment, without any essential or numerical change, and consequently with perfect identity, to exist in the new state of steam, or in the state of a chrystalline mass, as solid as the rock from which it hangs as an icicle, or that glitters with its gemmy covering.