s 3 8 



THE POPULAR SCIENCE MONTHLY. 



EDITOR'S TABLE. 



LOOSE AND ACCURATE KNOWL- 

 EDGE. 



IN explaining -what we understand by- 

 science, in the first number of this 

 monthly, it was stated to consist in 

 accurate as contrasted with lax and 

 careless thinking. "We had not then 

 space to show how a great deal of the 

 knowledge that is truly recognized as 

 scientific may be still so loose and im- 

 perfect as to be misleading. Let us, 

 therefore, briefly consider this aspect 

 of the case. 



There are two stages in the history 

 of science, and two states of mind 

 among so-called educated people, which 

 correspond to them. The first stage of 

 all science consisted simply in recog- 

 nizing the properties of bodies so as to 

 identify them. The characters were 

 made out which distinguished this 

 thing from that, and one kind of effect 

 from another. The first thing was to 

 determine the qualities of objects, and 

 this was the work in the early or quali- 

 tative stage in the progress of each 

 science. But, qualities being ascer- 

 tained, the next and inevitable step 

 was to bring them under the operation 

 of mathematics, which deals with the 

 laws of quantity. First, it was asked, 

 What are the properties or effects ? and 

 next, "What are their degrees, or what 

 quantities are involved in given results ? 

 This implies exact measurement, and is 

 known as the quantitative stage of sci- 

 ence. 



For example, bodies, which burn 

 and produce heat, have the property 

 of combustibility ; but the next question 

 is, How much heat will different bodies 

 produce in burning? It is a quality 

 of vinegar to unite with soda, and this 

 was ascertained in the qualitative in- 

 fancy of chemistry, but how much vin- 

 egar will combine with a given amount 



of soda was only determined with the 

 development of quantitative chemistry. 

 It is a quality of animals that they ex- 

 hale carbonic-acid gas in respiration, but, 

 when this was known, it became ne- 

 cessary to know the rates of exhalation 

 in the different tribes, and the varia 

 tions of these rates in sex, age, activity, 

 sleep, and disease. It is a quality of 

 ideas that they cohere with each other, 

 forming groups and trains by which 

 thinking becomes a connected and 

 orderly process ; but it is also a fact 

 that these cohesions are of unequal de- 

 grees of strength, and this gives rise to 

 a kind of quantitative psychology, which 

 is only imperfect because we lack the 

 means of exact measurement. 



Now, qualitative information is the 

 first indispensable step in the growth 

 of knowledge, and is just as truly "sci- 

 ence" as the knowledge of quantities; 

 but it is not the whole of science. 

 Qualitative chemistry must precede 

 and underlie quantitative chemistry, 

 and so with other departments. But, 

 to suppose that a mere knowledge of 

 qualities may pass for science is an error 

 leading to the worst practical conse- 

 quences. Current scientific knowledge, 

 however, is very much of this qualita- 

 tive sort. As it was first in the order 

 of development, because it is simplest, 

 it is also most widely diffused for the 

 same reason. This is one of the things 

 that is meant in saying that people 

 think vaguely and loosely, and reason 

 wildly, upon subjects in which science 

 is involved. For every thing in practi- 

 cal and applied science turns at last on 

 the question, lTow much? It is not 

 enough to know that a given substance 

 will produce a given effect ; we must 

 know the degree or amount of effect 

 before we can build upon it. It is this 

 scientific smattering with qualitative 

 notions that exposes people to all forms 



