FALLACIES OF OBSERVATION. 475 



not from observation, but from ibo notion we think oursolvos alilo to 

 form of the qiialiti(>s of the G()ilhea<l. This sort of infi'rence was 

 probal)ly never eairied to a i^reater length than it was in one particular 

 instance by Descartes, when, as a proof of one of his physical princi- 

 ples, that the quantity of motion in the universe is invariable, he had 

 recourse to the immutability of the Divine Nature. Optimism, in all 

 its shapes, is an examjile of the same sp(>cii's of fallacy: (rod is per- 

 fect, therefore what we think perfection nmst obtain in nature. Even 

 in our own time men do not cease to oppose the divine benevolence to 

 the evidence of physical facts, to the principle of population for ex- 

 ample. As if the subjection of mankind to physical sutt'erinir, often 

 entirely unavoidable, and, when capabli' of being warded oil', capable 

 only by means of forethought and self-restraint, were more dithcult to 

 reconcile with the ways of Providence in some one of its particular 

 manifestations than in so many others. As if, in so far as j)ain is an 

 imjierfection, any one day's experience were not sufficient to con- 

 vince the devoutest mind that imperfection, in that sense, in the work, 

 entered into the plans of the Creator, and that no attribute really 

 incompatible with it can be correctly ascribed to him. 



Although several other varieties of a priori fallacy might probably 

 be added to those here specified, these are all against which it seems 

 necessary to give any special caution. Our object is to open, without 

 attempting or aflecting to exhaust the subject. Having illustrated, 

 therefore, this first class of Fallacies at sufficient length, I shall pro- 

 ceed to the second. 



CHAPTER IV. 



FALLACIES OF OBSERVATION. 



§ 1. From the fallacies which are properly Prejudices, or presump- 

 tions antecedent to, and superseding, proof, we pass to those which lie 

 in the incorrect performance of the proving process. And as Proof, 

 in its widest extent, embraces oni^ or more or all of three processes, 

 Observation, Generalization, and Deduction; we shall consider in their 

 order the errors capable of being committed in these three operations. 

 And. first, of the first mentioned. 



A fallacy of misobserv'ation may be either negative or positive ; 

 either Non-observation or Mal-obsei-vation. It is non-observation, 

 when all the error consists in overlooking, or neglecting, facts or j)ar- 

 ticulars which ought to have been observed. It is mal-observation, 

 when something is not simply unseen, but seen wrong; when the fact 

 or phenomenon, instead of being recognized for what it is in reality, 

 is mistaken for something else. 



§ 2. Non-observation may either takc! j)laco by overlooking in.stances, 

 or by overlooking some of the circumstances of a given instance. If 

 we were to conclude that a fiirlune-feller was a true propliet, from not 

 adverting to the cases in which his jnedictions had been falsified by 

 the event, this would be non-observation of instances : but if we ov^r- 



