ETHOLOGY. 455 



produced in that case. But we must remember that a degree 

 of knowledge far short of the power of actual prediction, is 

 often of much practical value. There may be great power of 

 influencing phenomena, with a very imperfect knowledge of 

 the causes by which they are in any given instance determined. 

 It is enough that we know that certain means have a tendency 

 to produce a given effect, and that others have a tendency to 

 frustrate it. When the circumstances of an individual or of a 

 nation are in any considerable degree under our control, we 

 may, by our knowledge of tendencies, be enabled to shape those 

 circumstances in a manner much more favourable to the ends 

 we desire, than the shape which they would of themselves 

 assume. This is the limit of our power ; but within this limit 

 the power is a most important one. 



This science of Ethology may be called the Exact Science 

 of Human Nature ; for its truths are not, like the empirical 

 laws which depend on them, approximate generalizations, but 

 real laws. It is, however, (as in all cases of complex phe- 

 nomena) necessary to the exactness of the propositions, that 

 they should be hypothetical only, and affirm tendencies, not 

 facts. They must not assert that something will always, or 

 certainly, happen ; but only that such and such will be the 

 effect of a given cause, so far as it operates uncounteracted. 

 It is a scientific proposition, that bodily strength tends to 

 make men courageous ; not that it always makes them so : 

 that an interest on one side of a question tends to bias the 

 judgment; not that it invariably does so: that experience 

 tends to give wisdom ; not that such is always its effect. 

 These propositions, being assertive only of tendencies, are 

 not the less universally true because the tendencies may be 

 frustrated. 



5. While on the one hand Psychology is altogether, 

 or principally, a science of observation and experiment, 

 Ethology, as I have conceived it, is, as I have already re- 

 marked, altogether deductive. The one ascertains the simple 

 laws of Mind in general, the other traces their operation in 

 complex combinations of circumstances. Ethology stands to 



