LAW OP CAUSATION. 243 



the agent of a person's death, the whole of the vital and organic properties 

 of the patient are as actively instrumental as the poison, in the chain of ef- 

 fects which so rapidly terminates his sentient existence. In the process of 

 education, we may call the teacher the agent, and the scholar only the ma- 

 terial acted upon ; yet in truth all the facts which pre-existed in the schol- 

 ar's mind exert either co-operating or counteracting agencies in relation to 

 the teacher's efforts. It is not light alone which is the agent in vision, but 

 light coupled with the active properties of the eye and brain, and with 

 those of the visible object. The distinction between agent and patient is 

 merely verbal : patients are always agents ; in a great proportion, indeed, 

 of all natural phenomena, they are so to such a degree as to react forcibly 

 on the causes which acted upon them : and even when this is not the case, 

 they contribute, in the same manner as any of the other conditions, to the 

 production of the effect of which they are vulgarly treated as the mere the- 

 atre. All the positive conditions of a phenomenon are alike agents, alike 

 active ; and in any expression of the cause which professes to be complete, 

 none of them can with reason be excluded, except such as have already 

 been implied in the words used for describing the effect; nor by including 

 even these would there be incurred any but a merely verbal impropriety. 



§ 5. There is a case of causation which calls for separate notice, as it 

 possesses a peculiar feature, and presents a greater degree of complexity 

 than the common case. It often happens that the effect, or one of the ef- 

 fects, of a cause, is, not to produce of itself a certain phenomenon, but to 

 fit something else for producing it. In other words, there is a case of cau- 

 sation in which the effect is to invest an object with a certain property. 

 When sulphur, charcoal, and nitre are put together in certain proportions 

 and in a certain manner, the effect is, not an explosion, but that the mixture 

 acquires a property by which, in given circumstances, it will explode. The 

 various causes, natural and artificial, M'hich educate the human body or the 

 human mind, have for their principal effect, not to make the body or mind 

 immediately do any thing, but to endow it with certain properties — in oth- 

 er words, to give assurance that in given circumstances certain results will 

 take place in it, or as consequences of it. Physiological agencies often 

 have for the chief part of their operation to predispose the constitution to 

 some mode of action. To take a simpler instance than all these : putting 

 a coat of white paint upon a wall does not merely produce in those who 

 see it done, the sensation of white ; it confers on the wall the permanent 

 property of giving that kind of sensation. Regarded in reference to the 

 sensation, the putting on of the paint is a condition of a condition ; it is a 

 condition of the wall's causing that particular fact. The wall may have 

 been painted years ago, but it has acquired a property which has lasted till 

 now, and will last longer ; the antecedent condition necessary to enable the 

 wall to become in its turn a condition, has been fulfilled once for all. In a 

 case like this, where the immediate consequent in the sequence is a proper- 

 ty produced in an object, no one now supposes the property to be a sub- 

 stantive entity " inherent " in the object. What has been produced is what, 

 in other language, may be called a state of preparation in an object for pro- 

 ducing an effect. The ingredients of the gunpowder have been brought into 

 a state of preparation for exploding as soon as the other conditions of an 

 explosion shall have occurred. In the case of the gunpowder, this state of 

 preparation consists in a certain collocation of its pai'ticles relatively to one 

 another. In the example of the wall, it consists in a new collocation of two 



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