“The mind of man can never be wholly barren. Through our whole lives we are subject to successive impressions; for, either new ideas are continually flowing in, or traces of the old ones are marked deeper.”

Source: Joseph Allen (1979). The Leisure alternatives catalog: food for mind & body. p. 134

The Law of Mind (1892)
Context: Now, let there be an indefinite succession of these inferential acts of comparative perception; and it is plain that the last moment will contain objectively the whole series. Let there be, not merely an indefinite succession, but a continuous flow of inference through a finite time; and the result will be a mediate objective consciousness of the whole time in the last moment. In this last moment, the whole series will be recognized, or known as known before.

Part 1, Book 1, ch. 2, sect. 7.
Philosophy of the Inductive Sciences (1840)

Draft for a Statement of Human Obligation (1943)
Context: The proportions of good and evil in any society depend partly upon the proportion of consent to that of refusal and partly upon the distribution of power between those who consent and those who refuse.
If any power of any kind is in the hands of a man who has not given total, sincere, and enlightened consent to this obligation such power is misplaced.
If a man has willfully refused to consent, then it is in itself a criminal activity for him to exercise any function, major or minor, public or private, which gives him control over people's lives. All those who, with knowledge of his mind, have acquiesced in his exercise of the function are accessories to the crime.
Any State whose whole official doctrine constitutes an incitement to this crime is itself wholly criminal. It can retain no trace of legitimacy.
Any State whose official doctrine is not primarily directed against this crime in all its forms is lacking in full legitimacy.
Any legal system which contains no provisions against this crime is without the essence of legality. Any legal system which provides against some forms of this crime but not others is without the full character of legality.
Any government whose members commit this crime, or authorize it in their subordinates, has betrayed its function.

Confessions Of A Sceptic
The Nemesis of Faith (1849)
Context: Now, to a single-minded man, who is either brave enough or reckless enough to surrender himself wholly to one idea, and look neither right nor left, but only forward, what earthly consequences may follow is not material. Persecution strengthens him; and so he is sure he is right, whether his course end in a prison or on a throne is no matter at all. But men of this calibre are uncommon in any age or in any country — very uncommon in this age and this country.

The Human Condition (1958), part 3, chapter 16.

The Inferno (1917), Ch. XIV
Context: What am I? I am the desire not to die. I have always been impelled — not that evening alone — by the need to construct the solid, powerful dream that I shall never leave again. We are all, always, the desire not to die. This desire is as immeasurable and varied as life's complexity, but at bottom this is what it is: To continue to be, to be more and more, to develop and to endure. All the force we have, all our energy and clearness of mind serve to intensify themselves in one way or another. We intensify ourselves with new impressions, new sensations, new ideas. We endeavour to take what we do not have and to add it to ourselves. Humanity is the desire for novelty founded upon the fear of death. That is what it is.

Also reported as "One's mind" instead of "A man's mind", and "can never go back" or "never regains" instead of "never goes back"; most likely properly attributed to Oliver Wendell Holmes, Sr.
Misattributed