When Ruskin wrote this passage, he could count on a certain measure of agreement from his contemporaries that the essence of man himself is spirit, though certainly without any very exact notion being implied. This persuaded him to fight on behalf of the spirit, lest its activity on the lower levels of nature should not be duly acknowledged. To-day, when the purely physical conception of nature has laid hold of the entire man, Ruskin might have given his thought the following turn: ‘… and we shall certainly attain to no real insight into this creative force (of the spirit) at the level of man, unless we win the capacity to recognize its activity in lower states of matter.’