What does "latter" refer to here?

Does latter refer to "we are even told that a sensation can be said to be twice, thrice, four times as intense as another sensation of the same kind"?

Context:
It is usually admitted that states of consciousness, sensations, feelings, passions, efforts, are capable of growth and diminution; we are even told that a sensation can be said to be twice, thrice, four times as intense as another sensation of the same kind. This latter thesis, which is maintained by psychophysicists, we shall examine later; but even the opponents of psychophysics do not see any harm in speaking of one sensation as being more intense than another, of one effort as being greater than another, and in thus setting up differences of quantity between purely internal states.