The gospel of St. Matthew told of the angry Jesus driving the merchants and money-changers out of the temple, knocking over the tables of the money-c… - Freeman Dyson

once information has passed into protein it cannot get out again. . . . the transfer of information from nucleic acid to nucleic acid or from nucleic acid to protein may be possible, but transfer from protein to protein, or from protein to nucleic acid is impossible.

In contrast to Kuhn, Galison in his classic work Image and Logic, published in 1997, describes the history of particle physics as a history of tools rather than ideas. According to Image and Logic, the progress of science is tool-driven. The tools of particle physics are of two kinds, optical and electronic. The optical tools are devices such as cloud chambers, bubble chambers, and photographic emulsions, which display particle interactions visually by means of images. The images record the tracks of particles. An experienced experimenter can see at once from the image when a particle is doing something unexpected. Optical tools are more likely to lead to discoveries that are qualitatively new.

On the other hand, electronic tools are better for answering quantitative questions. Electronic detectors such as the Geiger counters that measure radioactivity in the cellars of old houses are based on logic. They are programmed to ask simple questions each time they detect a particle, and to record whether the answers to the questions are yes or no. They can detect particle collisions as at rates of millions per second, sort them into yes's and no's, and count the number that answered yes and the number that answered no. The history of particle physics may be divided into two periods, the earlier period ending about 1980 when optical detectors and images were dominant, and the later period when electronic detectors and logic were dominant. Before the transition, science advanced by making qualitative discoveries of new particles and new relationships between particles. After the transition, with the zoo of known particles more or less complete, the science advanced by measuring their interactions with greater and greater precision. In both periods, before and after the transition, tools were the driving force of progress.

Nobody knows what dark matter is. It is another deep mystery waiting to be explored. We know only that it is there, and that it weighs more than the stuff that we can see.