[Sidenote: Technical and scientific thinking.]
Clifford has made a distinction between technical and scientific thinking. The former enables one to do with skill and accuracy what has been done heretofore. The latter partakes of the nature of prophecy or prediction. He claims that scientific as well as merely technical thought make use of experience to direct human action, but that while technical thought or skill enables a man to deal with the same circumstances he has met before, scientific thought enables him to deal with circumstances different from any he has met before. In his opinion, scientific thought is human progress itself. An example or two can best be given in his own language.
“If you make a dot on a piece of paper, and then hold a piece of Iceland spar over it, you will see not one dot, but two. A mineralogist, by measuring the angles of a crystal, can tell you whether or not it possesses this property without looking through it. He requires no scientific thought to do that. But Sir Rowan Hamilton, the late Astronomer Royal of Ireland, knowing these facts, and also the explanation of them which Fresnel had given, thought about the subject, and predicted that by looking through certain crystals in a particular direction we should see not two dots, but a continuous circle. Mr. Lloyd made the experiment and saw the circle, a result which had never been even suspected. This has always been considered one of the most signal instances of scientific thought in the domain of physics. It is most distinctly an application of experience gained under certain circumstances to entirely different circumstances.”[44]
Clifford compares two well-known achievements in the domain of astronomy which help to set the distinction between technical and scientific thought in a still clearer light:
“Ancient astronomers observed that the relative motions of the sun and moon recurred all over again in the same order every nineteen years. They were thus enabled to predict the time at which eclipses would take place. A calculator at one of our great observatories can do a great deal more than this. Like them, he makes use of past experience to predict the future; but he knows of a great number of other cycles besides the one of nineteen years, and takes account of all of them; and he can tell about the solar eclipse of six years hence, exactly when it will be visible, and how much of the sun’s surface will be covered at each place, and to a second at what time of the day it will begin and finish there. This prediction involves technical skill of the highest order, but it does not involve scientific thought, as any astronomer will tell you. By such calculations the place of the planet Uranus at different times of the year had been predicted and set down. The predictions were not fulfilled. Then arose Adams, and from the errors in the prediction he calculated the place of an entirely new planet that had never yet been suspected; and you all know how the new planet was actually found in that place. Now this prediction does involve scientific thought, as any one who has studied it will tell you. Here, then, are two cases of thought about the same subject, both predicting events by the application of previous experience, yet we say one is technical and the other scientific.”[45]