lysis" Editor: FARKAS, ADELBERT, Philadelphia, Pennsylvania, 1956, Academic Press Inc., New York, 1957, p. 3301 and Edward L. King ["Catalysis" Editor: EMMETT, PAULH., Reinhold Publishing Corp., New York, 1955, Vol. 2, p: 4471. The reason for this discrepancy seems to be quite apparent. A negative catalyst is generally considered to be a substance that acts opposite to a (positive) catalyst; Young and Malik, however, consider the mode of action of a negative catalyst in providing an alternate path to the reaction with a higher activation energy (in cont,rast to a catalyst that provides an alternate path to the reaction with a lower activation energy). Abel, Emmett, and King, on the other hand, consider the mode of action of a negative catalyst to slow down the reaction irrespective of the mechanism involved in doing so. Also if we agree to the view expressed by Young and Malik, it is difficult to think of a mcchanism by which a negative catalyst can provide an alternate path to a reaction with a higher energy of activation. HAKAM SINGH K. L. MITTAL U X I V E R ~ TOFY SOUTHERN CALIFORNIA Los ANGELES,90007
T o the Editor: The point of controversy expressed by Professors Singh and Mittal seems to me to be philosophical-and worth further comment. Semantically, it hinges upon the significance of the word, negative. Thus, if we define a catalyst as a substance which by its action provides a reaction path of lower activation energy, then it is reasonable to define a negative catalyst oppositely, in terms that describe a reaction path of higher activation energy. And, as Professor Mittal says, "it is difficult to think of (such) a mechanism." Therefore, defined in this way, negative catalysts do not exist, effectively. On the other hand, if we define a catalyst as a substance which promotes the rate of a reaction, with respect to specified products, then it is reasonable to define a negative catalyst oppositely, as a substance which retards the rate of production of those products. This is substantially Professors Singh and Mittal's position; and, given their premise-definition, I agree. However, it seems to me to be proper to define anything in terms of its essence, rather than operationally, whenever this is possible. An operational definition is indeed useful, but always restricted to a specific (from which it derives its utility). So, I prefer to retain my position on this question. I hope that this further discussion will clarify the issue. Too often, teachers tell students that a negative catalyst is a substance which "raises the energy of activation," and Professors Singh and Mittal and I do all agree that such a statement is preposterous.
Uncertainty [Principle]
T o the Editor: My compliments to Hutchinson [J. CHEM.EDUC.,45, 600 (1968)l for his article on the relationship of science and scientific education to the world around us. I fnlly support the statement that abstraction readily transforms from servant to master [because] we don't fnlly accept the limitation of an abstraction. But can we get a deeper insight into this problem? Is it probable that it is of vital importance to human beings to have a feeling of an unambiguous orientation, and that because of this we often deny the limitation of an abstraction? I guess there must be something to this because many great scientists appear to evade the problem. I am often surprised at the random mixing of "interaction'' and "no interaction" in science. This erratic mixing seems to be generally accepted. An example: An interaction between elements (components) always appears to involve the impossibility of measuring one or more qualities of an element. Nevertheless we say that elements (atoms) interact, and that (at the same time) each element has one or more measurable qualities (a mass, a charge, etc.). This appears to be contrary to the laws of logic. We make trouble by operating (at the same time) with entirety (interaction) and "real" [incorruptible] individual particles. Although this inconsistency appears to lead to great difficultiesin communication (example: thermodynamics), and also seems to make it easy for men of fashion to "take over" more and more of scientific education, the major contributors to science seem to avoid the problem. Why? My explanation: Nearly all of us feel, that something important is lost, if we obey [only] the laws of thought. But what do we lose? By obeying the laws of thought, and by accepting, for example, that our moon, our earth, and our atoms interact, it is difficult to avoid relating their "qualities" to experimental operations. In fact, a reasonable communication in these and similar cases seems to be possible only by relating qualities to operations; we cannot retain the "well known" qualities of individual elements, e.g., our "familiar" [unaltered] atoms. I n this way, we lose images which we have had for centuries. I n their place we get operationally defined qualities (e.g., the operational definition of pH). Since these are related to experimental operations, limitation of the definitions may be expected. Is this too much to human beings to see beyond these limitations? Perhaps this also leads to that which we no more can state, i.e., that we are free, and that we (at the same time) interact with our surroundings? I t appears to be of fundamental importance to elucidate these difficulties. Is it possible to remove them? Have we to accept that even in science feelings are prior to reasoning? Is this the "real" hindrance to more profound understanding of the scientific language, and to a deeper insight into other problems, which are important to all of us?? BJORNBERGTHORSSON THETECHNICAL UNIVERSITY OF DENMARK COPENHAGEN
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Journal of Chemical Education
