The quotes are not in any particular order. Some come from an older, less fact-checked collection. Newer ones are added to the top.

  • “Another advantage of a mathematical statement is that it is so definite that it might be definitely wrong; and if it is found to be wrong, there is a plenteous choice of amendments ready in the mathematicians’ stock of formulae. Some verbal statements have not this merit; they are so vague that they could hardly be wrong, and are correspondingly useless.”
    • Lewis Fry Richardson, Mathematics of War and Foreign Politics. Cited from The World Of Mathematics [Vol 2], 1956, edited by James Roy Newman.
  • “The test of a first rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function.”
  • No one who has not taken the trouble to study these tests [IQ tests] in sufficient detail to recognize their possibilities and limitations is qualified to express on opinion on the ethic problem [whether any ethic/racial group is superior to any other]. There is, perhaps, no aspect of this problem more deserving of serious study by anthropologists than the systematic testing of cognitive ability. …
    • John Baker, Race, 1974
  • [Interview: Responding to a question about whether it was smart to publish his 1969 article at the time he did] In retrospect, however, I would hope that I would not have changed a thing in that article, even if I had been able to imagine the supposed “storm” it caused. I will be ashamed the day I feel I should knuckle under to social-political pressures about issues and research I think are important for the advance of scientific knowledge.
    • Arthur Jensen, Profiles in Research Author(s): Arthur Jensen, Daniel H. Robinson and Howard Wainer, Journal of Educational and Behavioral Statistics, Vol. 31, No. 3 (Autumn, 2006), pp. 327-352
  • The key theme in Gordon’s chapter, that lends it theoretical coherence, is his clear perception that the guiding force in my own work in mental measurement arises principally from my constant search for construct validity that can embrace the widest range of phenomena in differential psychology. In my philosophy, science is an unrelenting battle against ad hoc explanation. No other field in psychology with which I have been acquainted has been so infested by ad hoc theories as the attempts to explain social class, racial, and ethnic group differences on various tests of mental ability. My pursuit of what I have called the Spearman hypothesis (Jensen, 1985a), which is nicely explicated by Gordon, represents an effort to displace various ad hoc views of the black-white differences on psychometric tests by pointing out the relationship of the differences to the g loadings of tests, thereby bringing the black-white difference into the whole nomothetic network of the g construct. It is within this framework, I believe, that the black-white difference in psychometric tests and all their correlates, will ultimately have to be understood. Understanding the black-white difference is part and parcel of understanding the nature of g itself. My thoughts about researching the nature of g have been expounded in a recent book chapter (Jensen, 1986b). Enough said. Gordon’s chapter speaks for itself, and, with his three commentaries on the chapters by Osterlind, Shepard, and Scheuneman, leaves little else for me to add to this topic.
    • Arthur Jensen, pp. 430-1, Differential Psychology: Towards Consensus (1987)
  • I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be.
  • Now, if the ignorance of nature gave birth to Gods, the knowledge of nature is calculated to destroy them.
    • Baron d’Holbach, La Système de la nature; quoted in The Law of Reason, published by J. Thompson, p. 40.
      This is apparently the earliest statement of the god of the gaps argument.