344 FOOT-NOTES TO EVOLUTION. 
losophy this offers no difficulty. It is still plausible to 
suppose that by some combinations of primitive units 
these variant atoms are formed. Such an idea would 
have logical continuity, and as we are becoming used to 
notions of primal unity, we find such an idea satisfying 
to our consciousness. If this be true, somewhere, some- 
how, lead will be resolved into its primal elements, and 
these elements may be reunited in the form of gold. 
Then will the dream of the alchemist become fact; 
but not until then—which is a matter of the greatest 
importance. Such transmutation is as yet no part of 
knowledge. We certainly do not know that lead can be 
changed into that which is transmutable into gold. We 
do not know it, I say; but may we believe it? Is the 
foundation of belief less secure than that of knowledge? 
Can we trust philosophy to tell us what to believe, 
while we must look to science to tell us what we know? 
This brings us to the question of definitions. If 
knowledge and belief are of like rank, both must rest on 
science, and the results of philosophy must come to sci- 
ence only as hints or suggestions as to future lines of 
research. 4 
If knowledge implies stability, and belief does not, 
the relation of the two is also clear. In that case belief 
would be a word of light meaning, expressive of whim 
or of the balance of probabilities in association with 
prejudice. Belief would then be the pretense of knowl- 
edge, as compared with knowledge itself. Along its 
paths life can not march with courage and effectiveness. 
It is not for such beliefs as this that the martyrs lived or 
died. Their inspiration was the positive belief of science, , 
or the negative belief of the falsity of the ideas tyranny 
or superstition had forced upon them. 
To avoid a discussion foreign to my purpose, I wish, 
if possible, to separate the word “ belief,” as used in this 
