[About the great synthesis of atomic physics in the 1920s:] It was a heroic time. It was not the doing of any one man; it involved the collaboration of scores of scientists from many different lands. But from the first to last the deeply creative, subtle and critical spirit of Niels Bohr guided, restrained, deepened and finally transmuted the enterprise.

Another roof, another proof.
[His motto, as an itinerant between mathematical friends’ houses at which he collaborated.]

Before an experiment can be performed, it must be planned—the question to nature must be formulated before being posed. Before the result of a measurement can be used, it must be interpreted—nature's answer must be understood properly. These two tasks are those of the theorist, who finds himself always more and more dependent on the tools of abstract mathematics. Of course, this does not mean that the experimenter does not also engage in theoretical deliberations. The foremost classical example of a major achievement produced by such a division of labor is the creation of spectrum analysis by the joint efforts of Robert Bunsen, the experimenter, and Gustav Kirchoff, the theorist. Since then, spectrum analysis has been continually developing and bearing ever richer fruit.

Here I am: My brain is open.
[As an itinerant scholar, this was greeting he often gave, ready to collaborate, upon arrival at the home of any mathematician colleague.]

I have never had any student or pupil under me to aid me with assistance; but have always prepared and made my experiments with my own hands, working & thinking at the same time. I do not think I could work in company, or think aloud, or explain my thoughts at the time. Sometimes I and my assistant have been in the Laboratory for hours & days together, he preparing some lecture apparatus or cleaning up, & scarcely a word has passed between us; — all this being a consequence of the solitary & isolated system of investigation; in contradistinction to that pursued by a Professor with his aids & pupils as in your Universities.

If we ascribe the ejection of the proton to a Compton recoil from a quantum of 52 x 10⁶ electron volts, then the nitrogen recoil atom arising by a similar process should have an energy not greater than about 400,000 volts, should produce not more than about 10,000 ions, and have a range in the air at N.T.P. of about 1-3mm. Actually, some of the recoil atoms in nitrogen produce at least 30,000 ions. In collaboration with Dr. Feather, I have observed the recoil atoms in an expansion chamber, and their range, estimated visually, was sometimes as much as 3mm. at N.T.P.
These results, and others I have obtained in the course of the work, are very difficult to explain on the assumption that the radiation from beryllium is a quantum radiation, if energy and momentum are to be conserved in the collisions. The difficulties disappear, however, if it be assumed that the radiation consists of particles of mass 1 and charge 0, or neutrons. The capture of the a-particle by the Be⁹ nucleus may be supposed to result in the formation of a C¹² nucleus and the emission of the neutron. From the energy relations of this process the velocity of the neutron emitted in the forward direction may well be about 3 x 10⁹ cm. per sec. The collisions of this neutron with the atoms through which it passes give rise to the recoil atoms, and the observed energies of the recoil atoms are in fair agreement with this view. Moreover, I have observed that the protons ejected from hydrogen by the radiation emitted in the opposite direction to that of the exciting a-particle appear to have a much smaller range than those ejected by the forward radiation.
This again receives a simple explanation on the neutron hypothesis.

If we define 'thought collective' as a community of persons mutually exchanging ideas or maintaining intellectual interaction, we will find by implication that it also provides the special 'carrier' for the historical development of any field of thought, as well as for the given stock of knowledge and level of culture. This we have designated thought style.

If, for example, I had some idea, which, as it turned out would, say, be quite wrong, was going off of the tangent, Watson would tell me in no uncertain terms this was nonsense, and vice-versa. If he had some idea I didn’t like and I would say so and this would shake his thinking about it and draw him back again. And in fact, it’s one of the requirements for collaboration of this sort that you must be perfectly candid, one might almost say rude, to the person you are working with. It’s useless, working with somebody who’s either much too junior than yourself, or much too senior, because then politeness creeps in. And this is the end of all real collaboration in science.

My observations of the young physicists who seem to be most like me and the friends I describe in this book tell me that they feel as we would if we had been chained to those same oars. Our young counterparts aren’t going into nuclear or particle physics (they tell me it’s too unattractive); they are going into condensed-matter physics, low-temperature physics, or astrophysics, where important work can still be done in teams smaller than ten and where everyone can feel that he has made an important contribution to the success of the experiment that every other member of the collaboration is aware of. Most of us do physics because it’s fun and because we gain a certain respect in the eyes of those who know what we’ve done. Both of those rewards seem to me to be missing in the huge collaborations that now infest the world of particle physics.

Our ultimate end must be precisely what Dr. Pauling says, peace based on agreement, upon understanding, on universally agreed and enforced law. I think this is a wonderful idea, but peace based on force buys us the necessary time, and in this time we can work for better understanding, for closer collaboration.

Science is a collaborative effort. The combined results of several people working together is often much more effective than could be that of an individual scientist working alone.

Science is a field which grows continuously with ever expanding frontiers. Further, it is truly international in scope. … Science is a collaborative effort. The combined results of several people working together is often much more effective than could be that of an individual scientist working alone.

The advancement of science is slow; it is effected only by virtue of hard work and perseverance. And when a result is attained, should we not in recognition connect it with the efforts of those who have preceded us, who have struggled and suffered in advance? Is it not truly a duty to recall the difficulties which they vanquished, the thoughts which guided them; and how men of different nations, ideas, positions, and characters, moved solely by the love of science, have bequeathed to us the unsolved problem? Should not the last comer recall the researches of his predecessors while adding in his turn his contribution of intelligence and of labor? Here is an intellectual collaboration consecrated entirely to the search for truth, and which continues from century to century.
[Respecting how the work of prior researchers had enabled his isolation of fluorine.]

The individual within the collective is never, or hardly ever, conscious of the prevailing thought style, which almost always exerts an absolutely compulsive force upon his thinking and with which it is not possible to be at variance.

To fully understand the mathematical genius of Sophus Lie, one must not turn to books recently published by him in collaboration with Dr. Engel, but to his earlier memoirs, written during the first years of his scientific career. There Lie shows himself the true geometer that he is, while in his later publications, finding that he was but imperfectly understood by the mathematicians accustomed to the analytic point of view, he adopted a very general analytic form of treatment that is not always easy to follow.

What Pasteur and Langmuir believed—and what history has shown—is that both epidemiologists and laboratory scientists can make independent discoveries that have significant scientific impact, but collaboration across these disciplines has a synergistic effect, yielding public health data that are stronger than either discipline can provide alone