nor to limit in any way its powers or its results, but only to prevent its contamination by what would degrade and cripple it." And these tactics have been repeated at every great step of advancement. It is never genuine science that breaks over the old limits of opinion, but always "pretended science," "pseudo-science," and "science falsely so called."
In our correspondent's opinion, science has now attained a position in which it holds its destiny in its own hands, and is in no danger save from the folly of its own partisans. His theory of the case is, that science is now endangered by excess of theory. But, if that be the case, it is threatened by its own breath of life. A theory is only a view taken by the mind in its effort at explanation, and cannot be dispensed with, if observation and experiment are to be put to their true use. He says that science demands of its votary, "not what you think about it, but what you know." But what is knowing but thinking brought to the highest certainty? and how can this end be reached except by the successive steps of conjecture and hypothesis? As Dr. Whewell observes, "To try wrong guesses is apparently the only way to hit upon right ones." It is not Science which puts an embargo upon thinking and theorizing, for it is by these that all her laws have been arrived at. Of course, science demands certainty, demonstration, and experimental exactitude, if obtainable; and if not, then the nearest approach to them possible; but these must have an ideal and a meaning, or there can be no science. Science is not manipulation, but the thinking that accompanies it, and the theory or view that is established by it. Under the rigid rule laid down by the writer, the giant intellects who have made the epochs of science could never have got a hearing. Copernicus, Galileo, Columbus, Newton, Harvey, Dufay, Young, and Dalton, are known to the world as thinkers, and have gained immortality in science, and guided the multitude of lesser men by their theories. Faraday remarks that the world little knows how many conjectures and hypotheses, which arise in the minds of philosophers, are crushed by the severity of their own adverse criticism; but the world does know something of the number of theories that are submitted to the tribunal of science, and are crushed by the adverse criticism there encountered. Are these efforts of theory, therefore, in either case, to be interdicted or discouraged? Our correspondent has little patience with theories, but they are the measure of mental activity and the essential form of its scientific expression, as their inexorable testing is the measure of sound scientific method. There may be peril in theorizing, as there is in steam, but it is the condition of getting on; and, because brakes are useful, let us not put out the fires.
If there is more theorizing now than ever before, it is because there is far more extensive scientific activity. There is, indeed, greater demand for it now than ever, for the numbers of observers and experimenters who either cannot think or are afraid to think have greatly multiplied in recent years, increasing the mass of observations and fragmentary results, which can only be organized into accepted theory by the highest order of minds. Generalizations and inductions which bind up isolated facts in manageable form, and which constitute the very texture of science, are only to be arrived at by thinking and theorizing. And with the multitude of men thoroughly trained in all departments, and sharpened to the work of criticism, there is certainly less danger now than ever that worthless theories should gain the ascendency.
The hypothesis, that in future science can suffer no damage save from enemies in its own household, we ven-
