144 ADVANCEMENT OF LEARNING 



part level to the human mind, on account of their affinity. 

 We are, indeed, forbid in Scripture to worship angels, or to 

 entertain fantastical opinions of them, 6 so as to exalt them 

 above the degree of creatures, or to think of them higher 

 than we have reason; but the sober inquiry about them, 

 which either ascends to a knowledge of their nature by the 

 scale of corporeal beings, or views them in the mind, as in 

 a glass, is by no means forbid. The same is to be under 

 stood of revolted or unclean spirits: conversation with them, 

 or using their assistance, is unlawful; and much more in 

 any manner to worship or adore them: but the contem 

 plation and knowledge of their nature, power, and illu 

 sions, appears from Scripture, reason, and experience, to 

 be no small part of spiritual wisdom. Thus says the 

 apostle, * Strategematum ejus non ignari sumus. &quot; 7 And 

 thus it is as lawful in natural theology to investigate the 

 nature of evil spirits, as the nature of poisons in physics, 

 or the nature of vice in morality. But this part of knowl 

 edge relating to angels and spirits, which we call the ap 

 pendage to natural theology, cannot be noted for deficient, 

 as having been handled by many; but we may justly tax 

 no small part of the writers in this way, either with levity, 

 superstition, or fruitless speculation. 



CHAPTEH III 



Natural Philosophy divided into Speculative and Practical. The Neces 

 sity of keeping these Two Branches distinct 



BUT to leave natural theology, and proceed to natural 

 philosophy ; as it was well said by Democritus, that 

 &quot;the knowledge of nature lies concealed in deep 

 mines and caves&quot;; 1 and by the alchemists, that &quot;Yulcan 

 is a second nature, imitating concisely what the first takes 

 time and circuit to effect&quot;; 3 suppose natural philosophy 



6 St. Paul, Coloss. ii. 5, 18. 7 II. Cor. ii. 11. 



1 Laertius, Life of Seneca. 2 Paracelsus de Philos. Sagac. 



