40 On Mechanical Science. 



It has been usual to refer to motion, instead of force or 

 power ; but this is clearly beginning at the wrong end, motion 

 being merely the result of the action of unresisted power. Our 

 sense of feeling informs us that motion is a consequence of 

 our power being exerted so as to exceed the resistance. 



Force, denoting the mtensity of the action of power, may 

 be considered to flow equably or unequably with time ; it may 

 also be considered in relation to space, and to space and time 

 conjointly. The variation with regard to time, I do not re- 

 collect havmg seen considered. Natural phsenomena should 

 only be looked into for suggesting branches of research, not 

 as the objects and end of them ; and whatever advantage it 

 may give to ordinary readers, their use in illustration should 

 be avoided ; the Elements of Euclid in this respect should be 

 an example to imitate. 



Might not the sciences relating to the mind equally profit by 

 attending to the mode by which we obtain our ideas of mo- 

 tion? Could the system of Hume stand the test of such an in- 

 quiry ? even with the ponderous support which Brown has 

 endeavoured to place under it ? Have we not as distinct a 

 perception of the possession of power as we have of the order 

 of sequence? The eye and the ear are not the only organs 

 of sense capable of affording us correct ideas ; indeed, neither 

 of them could inform us of the existence of matter; and be- 

 sides, these organs themselves, when e^jamined, appear to con- 

 vey impressions to the mind by an operation analogous to that 

 which conveys the. perception of feeling, showing that no im- 

 pression whatever is transmitted to the mind except by the 

 action of force, or power. I will go a step further, and ques- 

 tion the possibility of our knowing of the existence of any part 

 of the external world, miless we can either touch it directly or 

 indirectly, by the intervention .qf a medium between it and our 

 organs of sense. 



He who reasons respecting events by the order of sequence, 

 confines himself to an imperfect view of the subject. We must 

 advance another step, and inquire by what means forms of 

 matter endure : it then becomes necessary to consider causes 

 and effects as they exist, and not as they succeed one another ; 

 for they must exist together, to constitute a cause and an ef- 

 fect ; the order of events being only the circumstances neces- 

 sary to vary causes in their action. 



He who began his researches by saying, " I think, and 

 therefore I am," might with still greater propi'iety have said, 

 " I have powei', and therefore I am :" and h'^ certainly indi- 

 cated a true doctrine in referring to the human mind itself for 

 the first elements of sound philosophy. D — r-x. 



VIII. A further 



