"I am not disposed to bewail the limitations imposed by human ignorance. On the contrary, I feel ignorance is a healthful stimulant; and my enforced conviction that neither I nor anyone can possibly lay down beforehand what does not exist in the universe, or even what is not going on all round us everyday of our lives, leaves me with a cheerful hope that something very new and very arresting may turn up anywhere at any minute. … I shall try to utilize this temper of mind today by clearing away, so far as I can, certain presuppositions, on one side or on the other, which seem to me to depend upon a too hasty assumption that we know more about the universe than as yet we really can know."

“In old Egyptian days a well known inscription was carved over the portal of the temple of Isis: "I am whatever hath been, is, or ever will be; and my veil no man hath yet lifted." Not thus do modern seekers after truth confront nature — the word that stands for the baffling mysteries of the universe. Steadily, unflinchingly, we strive to pierce the inmost heart of Nature, from what she is to reconstruct what she has been, and to prophesy what she yet shall be. Veil after veil we have lifted, and her face grows more beautiful, august, and wonderful with every barrier that is withdrawn.”

“It can scarcely be denied that the fundamental phenomena which first led mankind into chemical inquiries are those of combustion. But, as we have just seen, minimized beings would be unable to produce fire at will, except by certain chemical reactions, and would have little opportunity of examining its nature. They might occasionally witness forest fires, volcanic eruptions, etc.; but such grand and catastrophic phenomena, though serving to reveal to our supposed Lilliputians the existence of combustion, would be ill suited for quiet investigation into its conditions and products. Moreover, considering the impossibility they would experience of pouring water from one test tube to another, the ordinary operations of analytical chemistry and of all manipulations depending on the use of the pneumatic trough would remain forever a sealed book.”

“The human creature represents the most perfect thinking and acting machine yet evolved on this earth, developing through countless ages in strict harmony with the surrounding conditions of temperature, atmosphere, light, and gravitation. The profound modifications in the human frame, which any important alteration in either of these factors would occasion, are strangely unconsidered. It is true there have been questionings as to the effects that might be occasioned by changes in temperature and atmospheric composition, but possible variations in gravitation seem almost to have escaped notice. The human body, which long experience and habit have taught us to consider in its highest development as the perfection of beauty and grace — "formed in the image of God " — is entirely conditioned by the strength of gravitation on this globe. So far as has been possible to ascertain, the intensity of gravity has not varied appreciably within those geologic ages covering the existence of animated thinking beings.”

“William Crookes : A Victorian Man of Science" by Cyril Norman Hinshelwood”

“It is remarkable how much of the utilised information men possess has been derived from the observations of astronomers. The mechanism of the universe was known before Harvey discovered the circulation of the blood, or Watt constructed a steam engine. The astronomers seem to have been the pioneers of every branch of human knowledge. The Old and the New Testament open astronomically: "In the beginning God created the heaven and the earth" . "The wise men from the east came to Jerusalem, saying, where is He that is born King of Jews? for we have seen His star in the east" . It must be remembered that the science of astronomy in one important respect differs from all other sciences. Astronomers are observers only - they ascertain causes by watching effects. They cannot interfere with or alter the causes in operation.”

“If a possible — nay, reasonable — variation in only one of the forces conditioning the human race, that of gravitation, could so modify our outward form, appearance, and proportions as to make us to all intents and purposes a different race of beings; if mere differences of size can cause some of the most simple facts in chemistry and physics to take so widely different a guise; if beings microscopically small and prodigiously large would simply as such be subject to the hallucinations I have pointed out, and to others I might enlarge upon, is it not possible that we, in turn, though occupying, as it seems to us, the golden mean, may also by the mere virtue of our size and weight fall into misinterpretations of phenomena from which we should escape were we or the globe we inhabit either larger or smaller, heavier or lighter? May not our boasted knowledge be simply conditioned by accidental environments, and thus be liable to a large element of subjectivity hitherto unsuspected and scarcely possible to eliminate?”