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proves that they are derived from experience : they may, in 

 reply to our image, say, that truths are stuck into the mind 

 by experience, as seeds are stuck into the ground ; and that 

 to maintain that they can grow under any other conditions, 

 is to hold the 'doctrine of spontaneous generation, which 

 equally untenable in the intellectual and in the physi 

 world. I shall not however here resume the general di 

 cussion ; but shall only say briefly in reply, that Axioms, 

 for instance, this Axiom, that material substances cannot 

 created or annihilated by any process which we can apply. 

 though it becomes evident in the progress of experienc 

 cannot be derived from experience; for it is a propositio 

 which never has been nor can be proved by experience; bu 

 which, nevertheless, has been always assumed by men, seek 

 ing for general truths, as necessarily true, and as controllin 

 and correcting all possible experience. And with regard 

 the image of vegetable developement, I may say, that 

 such developement implies both inherent forms in the livin 

 seed, and nutritive powers in earth and air; so the de 

 lopement of our scientific ideas implies both a formativi 

 power, and materials acted on ; and that, though the analo, 

 must be very defective, we conceive that we best follow it b; 

 placing the formative power in the living mind, and in the 

 external world the materials acted on : while the doctrine 

 that all truth is derived from experience only, appears to 

 reject altogether one of these elements, or to assert the two 

 to be one. 



