304 ANIMAL FORCES. [ii. 



may be prevented by natural obstacles, and thus the movements 

 may never take place (136 — 139), it follows that animals may, 

 in the natural state, exhibit direct or indirect nerve-actions of 

 external impressions, which never occur as sentient actions of 

 their external sensation, and never can. Direct physiological 

 illustrations are almost impossible, for the reasons stated, §§ 583 

 and 586, and the proofs can only be argumentative. The 

 morbid condition affords an illustration in those cases in which 

 a limb, still possessed of sensation, cannot be excited to those 

 movements by external impressions, of which in a natural con- 

 dition it is capable (127). 



592. When an internal impression depends on sensational 

 conceptions, as imaginations, foreseeings, feelings [Reizungen], 

 desires, aversions, instincts, instinctive emotions, and various 

 passions, the movements it excites are both sentient actions of 

 the conceptions and nerve-actions of the external impression 

 that causes the external sensation upon which they depend. 

 They are nerve-actions, because they can be excited when there 

 is no sensation; they are sentient actions, because all these 

 sensational conceptions develop no other sentient actions than 

 movements that are identical with those excited by the external 

 sensation itself. The probable object of nature, in thus uniting 

 the action of the cerebral forces and of the vis ne^^vosa, in the 

 movements of external sensations, and of sensational conceptions, 

 desires, and aversions, has been already referred to (184, ii, 

 370, 371). 



593. When an internal impression arises from the higher 

 passions, from intellectual conceptions and motives, and from 

 desires and aversions of the will and their satisfaction, the 

 movements it excites, in so far as these intellectual conceptions, 

 &c., are unmingled with sensational conceptions, are solely 

 sentient actions, and there is no combined action of the cere- 

 bral forces and the vis nervosa in their production. They are 

 not dependent on any external impression, and consequently 

 cannot be nerve-actions induced by the vis nervosa, and the only 

 other animal forces are the cerebral (353 — 356). Nature has 

 granted this higher species of conceptions to the most perfect 

 animals only, whose souls are not simply sensational [Sinnlich] , 

 but spiritual [Geister], (Baumgarten^s ^ Metaphysics,^ §' 590). 



594. Those err who conclude, that because an animal per- 



