Extraterrestrial Life Debate, Antiquity to 1915: A Source Book

10. BEFORE THE WHEWELL DEBATE

BEFORE THE WHEWELL DEBATE SIR JOHN HERSCHEL (1792–1871) John Herschel, the only son of William Herschel, attained, like his father, great eminence in astronomy. Moreover, John’s accomplishments in mathematics, physics, photography, philosophy of science, and other areas led to his being seen by his contemporaries as the leading British scientist of the mid-nineteenth century. In the field of astronomy, the younger Herschel wrote a text that was authoritative for much of the nineteenth century. This was his Treatise on Astronomy (1833), which he expanded into his Outlines of Astronomy (1849). Also like his father, John Herschel used a giant telescope to observe nebulous objects; in fact, in the 1830s, he spent four years at the Cape of Good Hope observing the heavens of the Southern Hemisphere. John Herschel also endorsed the doctrine of a plurality of worlds and incorporated it into a number of his writings. John Herschel, Treatise on Astronomy (London: Longman, Rees, Orme, Brown, Green, & Longman, 1833), 1–2. INTRODUCTION. (1.) In entering upon any scientific pursuit, one of the student ’s first endeavours ought to be, to prepare his mind for T T E E N N 297 f r o m 1 8 0 0 t o 1 8 6 0 298 the reception of truth, by dismissing, or at least loosening his hold on, all such crude and hastily adopted notions respecting the objects and relations he is about to examine as may tend to embarrass or mislead him; and to strengthen himself, by something of an effort and a resolve, for the unprejudiced admission of any conclusion which shall appear to be supported by careful observation and logical argument, even should it prove of a nature adverse to notions he may have previously formed for himself, or taken up, without examination , on the credit of others. Such an effort is, in fact, a commencement of that intellectual discipline which forms one of the most important ends of all science. It is the first movement of approach towards that state of mental purity which alone can fit us for a full and steady perception of moral beauty as well as physical adaptation. It is the “euphrasy and rue”[1] with which we must “purge our sight” before we can receive and contemplate as they are the lineaments of truth and nature. (2.) There is no science which, more than astronomy, stands in need of such a preparation, or draws more largely on that intellectual liberality which is ready to adopt whatever is demonstrated, or concede whatever is rendered highly probable, however new and uncommon the points of view may be in which objects the most familiar may thereby become placed. Almost all its conclusions stand in open and striking contradiction with those of superficial and vulgar observation, and with what appears to every one, until he has understood and weighed the proofs to the contrary, the most positive evidence of his senses. Thus, the earth on which he stands, and which has served for ages as the unshaken foundation of the firmest structures, either of art or nature, is divested by the astronomer of its attribute of fixity, and conceived by him as turning swiftly on its centre, and at 1. [This is a phrase from John Milton’s famous epic poem Paradise Lost, where the Archangel Michael uses the herbs “euphrasy and rue” to cleanse Adam’s eyes. See Milton’s Paradise Lost, book 11, line 414. MJC] the same time moving onwards through space with great rapidity. The sun and the moon, which appear to untaught eyes round bodies of no very considerable size, become enlarged in his imagination into vast globes,——the one approaching in magnitude to the earth itself, the other immensely surpassing it. The planets, which appear only as stars somewhat brighter than the rest, are to him spacious, elaborate, and habitable worlds; several of them vastly greater and far more curiously furnished than the earth he inhabits , as there are also others less so, and the stars themselves properly so called, which to ordinary apprehension present only lucid sparks or brilliant atoms, are to him suns of various and transcendent glory——effulgent centres of life and light to myriads of unseen worlds: so that when, after dilating his thoughts to comprehend the grandeur of those ideas his calculations have called up, and exhausting his imagination and the powers of his language to...