“Of courage undaunted, possessing a firmness and perseverance of purpose which nothing but impossibilities could divert from its direction, careful as a father of those committed to his charge, yet steady in the maintenance of order and discipline, intimate with the Indian character, customs, and principles; habituated to the hunting life, guarded by exact observation of the vegetables and animals of his own country against losing time in the description of objects already possessed; honest, disinterested, liberal, of sound understanding, and a fidelity to truth so scrupulous that whatever he should report would be as certain as if seen by ourselves – with all these qualifications as if selected and implanted by nature in one body for this express purpose, I could have no hesitation in confiding the enterprise to him. To fill up the measure desired, he wanted nothing but a greater familiarity with the technical language of the natural sciences, and readiness in the astronomical observations necessary for the geography of his route. To acquire these he repaired immediately to Philadelphia, and placed himself under the tutorage of the distinguished professors of that place.”

“No one is accountable for existing at all, or for being constituted as he is, or for living in the circumstances and surroundings in which he lives. The fatality of his nature cannot be disentangled from the fatality of all that which has been and will be. He is not the result of a special design, a will, a purpose; he is not the subject of an attempt to attain an 'ideal of man' or an 'ideal of happiness' or an 'ideal of morality'--it is absurd to want to hand over his nature to some purpose or other. We invented the concept 'purpose': in reality purpose is lacking...One is necessary, one is a piece of fate, one belongs to the whole, one is in the whole--there exists nothing which could judge, measure, compare, condemn our being, for that would be to judge, measure, condemn the whole...”

“The belief that science proceeds from observation to theory is still so widely and so firmly held that my denial of it is often met with incredulity. I have even been suspected of being insincere- of denying what nobody in his senses would doubt.But in fact the belief that we can start with pure observation alone, without anything in the nature of a theory is absurd; as may be illustrated by the story of the man who dedicated his life to natural science, wrote down everything he could observe, and bequeathed his priceless collection of observations to the Royal Society to be used as evidence. This story should show us that though beetles may profitably be collected, observations may not.Twenty-five years ago I tried to bring home the same point to a group of physics students in Vienna by beginning a lecture with the following instructions : 'Take pencil and paper; carefully observe, and write down what you have observed!' They asked, of course, what I wanted them to observe. Clearly the instruction, 'Observe!' is absurd. (It is not even idiomatic, unless the object of the transitive verb can be taken as understood.) Observation is always selective. It needs a chosen object, a definite task, an interest, a point of view, a problem. And its description presupposes a descriptive language, with property words; it presupposes similarity and classification, which in their turn presuppose interests, points of view, and problems.”

“An anxiety with no object or purpose in the present, and in the future nothing but endless sacrifice, by means of which he would attain nothing - that was what his days on earth held in store for him... What good was life to him? What prospects did he have? What did he have to strive for? Was he to live merely in order to exist? But a thousand times before he had been ready to give up his existence for an idea, for a hope, even for an imagining. Existence on its own had never been enough for him; he had always wanted more than that. Perhaps it was merely the strength of his own desires that made him believe he was a person to whom more was allowed than others.”

“Sherlock Holmes closed his eyes and placed his elbows upon the arms of his chair, with his finger-tips together. “The ideal reasoner,” he remarked, “would, when he had once been shown a single fact in all its bearings, deduce from it not only all the chain of events which led up to it but also all the results which would follow from it. As Cuvier could correctly describe a whole animal by the contemplation of a single bone, so the observer who has thoroughly understood one link in a series of incidents should be able to accurately state all the other ones, both before and after. We have not yet grasped the results which the reason alone can attain to. Problems may be solved in the study which have baffled all those who have sought a solution by the aid of their senses. To carry the art, however, to its highest pitch, it is necessary that the reasoner should be able to utilise all the facts which have come to his knowledge; and this in itself implies, as you will readily see, a possession of all knowledge, which, even in these days of free education and encyclopaedias, is a somewhat rare accomplishment. It is not so impossible, however, that a man should possess all knowledge which is likely to be useful to him in his work, and this I have endeavoured in my case to do.”

“He was, I take it, the most perfect reasoning and observing machine that the world has seen, but as a lover he would have placed himself in a false position. He never spoke of the softer passions, save with a gibe and a sneer. They were admirable things for the observer- excellent for drawing the veil from men's motives and actions. But for the trained observer to admit such intrusions into his own delicate and finely adjusted temperament was to introduce a distracting factor which might throw a doubt upon all his mental results. Grit in a sensitive instrument, or a crack in one of his own high-power lenses, would not be more disturbing than a strong emotion in a nature such as his.”