“No quality of human nature is more remarkable, both in itself and in its consequences, than that propensity we have to sympathize with others, and to receive by communication their inclinations and sentiments, however different from, or even contrary to our own. This is not only conspicuous in children, who implicitly embrace every opinion propos’d to them; but also in men of the greatest judgment and understanding, who find it very difficult to follow their own reason or inclination, in opposition to that of their friends and daily companions. To this principle we ought to ascribe the great uniformity we may observe in the humours and turn of thinking of those of the same nation; and ’tis much more probable, that this resemblance arises from sympathy, than from any influence of the soil and climate, which, tho’ they continue invariably the same, are not able to preserve the character of a nation the same for a century together. A good-natur’d man finds himself in an instant of the same humour with his company; and even the proudest and most surly take a tincture from their countrymen and acquaintance. A chearful countenance infuses a sensible complacency and serenity into my mind; as an angry or sorrowful one throws a sudden dump upon me. Hatred, resentment, esteem, love, courage, mirth and melancholy; all these passions I feel more from communication than from my own natural temper and disposition. So remarkable a phaenomenon merits our attention, and must be trac’d up to its first principles.”

"On the Tendency of Sects"
The Round Table (1815-1817)
Context: There is a natural tendency in sects to narrow the mind.
The extreme stress laid upon difierences of minor importance, to the neglect of more general truths and broader views of things, gives an inverted bias to the understanding; and this bias is continually increased by the eagerness of controversy, and captious hostility to the prevailing system. A party-feeling of this kind once formed will insensibly communicate itself to other topics; and will be too apt to lead its votaries to a contempt for the opinions of others, a jealousy of every difference of sentiment, and a disposition to arrogate all sound principle as well as understanding to themselves, and those who think with them. We can readily conceive how such persons, from fixing too high a value on the practical pledge which they have given of the independence and sincerity of their opinions, come at last to entertain a suspicion of every one else as acting under the shackles of prejudice or the mask of hypocrisy. All those who have not given in their unqualified protest against received doctrines and established authority, are supposed to labour under an acknowledged incapacity to form a rational determination on any subject whatever. Any argument, not having the presumption of singularity in its favour, is immediately set aside as nugatory. There is, however, no prejudice so strong as that which arises from a fancied exemption from all prejudice. For this last implies not only the practical conviction that it is right, but the theoretical assumption that it cannot be wrong. From considering all objections as in this manner "null and void,” the mind becomes so thoroughly satisfied with its own conclusions, as to render any farther examination of them superfluous, and confounds its exclusive pretensions to reason with the absolute possession of it.

The Sayings of Light and Love

Introductio ad prudentiam: Part II (1727)

Summa Contra Gentiles, III,126,3

On Boswell’s Life of Johnson (1831)

Aphorism 45
Novum Organum (1620), Book I
Context: The human understanding is of its own nature prone to suppose the existence of more order and regularity in the world than it finds. And though there be many things in nature which are singular and unmatched, yet it devises for them parallels and conjugates and relatives which do not exist. Hence the fiction that all celestial bodies move in perfect circles, spirals and dragons being (except in name) utterly rejected.

The Doll (1887–1889)

Preface
The History and Present State of Electricity (1767)
Context: The history of philosophy enjoys, in some measure, the advantages both of civil and natural history, whereby it is relieved from what is most tedious and disgusting in both. Philosophy exhibits the powers of nature, discovered and directed by human art. It has, therefore, in some measure, the boundless variety with the amazing uniformity of the one, and likewise every thing that is pleasing and interesting in the other. And the idea of continual rise and improvement is conspicuous in the whole study, whether we be attentive to the part which nature, or that which men are acting in the great scene.
It is here that we see the human understanding to its greatest advantage, grasping at the noblest objects, and increasing its own powers, by acquiring to itself the powers of nature, and directing them to the accomplishment of its own views; whereby the security, and happiness of mankind are daily improved. Human abilities are chiefly conspicuous in adapting means to ends, and in deducing one thing from another by the method of analogy; and where may we find instances of greater sagacity, than in philosophers diversifying the situations of things, in order to give them an opportunity of showing their mutual relations, affections, and influences; deducing one truth and one discovery from another, and applying them all to the useful purposes of human life.
If the exertion of human abilities, which cannot but form a delightful spectacle for the human imagination, give us pleasure, we enjoy it here in a higher degree than while we are contemplating the schemes of warriors, and the stratagems of their bloody art.

The Great Infidels (1881)
Context: Most men are followers, and implicitly rely upon the judgment of others. They mistake solemnity for wisdom, and regard a grave countenance as the title page and Preface to a most learned volume. So they are easily imposed upon by forms, strange garments, and solemn ceremonies. And when the teaching of parents, the customs of neighbors, and the general tongue approve and justify a belief or creed, no matter how absurd, it is hard even for the strongest to hold the citadel of his soul. In each country, in defence of each religion, the same arguments would be urged.