Date: 1690, 1694, 1695, 1700, 1706

"For, though he that contemplates the Operations of his Mind, cannot but have plain and clear Ideas of them; yet unless he turn his Thoughts that way, and considers them attentively, he will no more have clear and distinct Ideas of all the Operations of his Mind, and all that may be observed ther...

— Locke, John (1632-1704)

Date: August 27, 1751

"The painted vales of imagination are deserted, and our intellectual activity is exercised in winding through the labyrinths of fallacy, and toiling with firm and cautious steps up the narrow tracks of demonstration."

— Johnson, Samuel (1709-1784)

Date: 1754

"This is the great intellectual province, wherein our minds range with much freedom, and often with exorbitant licence, in the pursuit of real or imaginary science."

— St John, Henry, styled first Viscount Bolingbroke (1678-1751)

Date: 1759

"His mighty mind travelled round the intellectual world; and, with a more than eagle's eye, saw, and has pointed out blank spaces, or dark spots in it, on which the human mind never shone."

— Young, Edward (bap. 1683, d. 1765)

Date: September 1, 1759.

"The incursions of troublesome thoughts are often violent and importunate; and it is not easy to a mind accustomed to their inroads to expel them immediately by putting better images into motion; but this enemy of quiet is above all others weakened by every defeat; the reflection which has been o...

— Johnson, Samuel (1709-1784)

Date: 1763 (repr. 1776); 1794 (repr. 1799)

"When the senses are gently and naturally shut up, and the command over the body intermitted, as in sleep, if we think at all we are said to dream; and generally wander through airy tracks of thought, which have no agreement with each other, nor are at all corrected by the judgment."

— Doddridge, Philip (1702-1751)