4. General Reflections on Heai. 
I shall attempt to show by and by ; but Lavoisier’s docirine 
will still be only limited and not disearded. 
When, however, we meet with a list of the-different theo- 
ries which have been proposed to account for the same thing, 
and see how each one supplanted all its predecessors, and 
was itselfsupplanted in its turn; when wesee, moreover, that 
the theory of Lavoisier, though at one time held to be a de- 
monstration, is nevertheless still deemed erroneous by some 
and inadequate by others; we are apt to imagine that this 
is no better than those that have gone before it, and that it 
will ere long share the same fate. But let us reflect, that 
Lavoisier differed from all his predecessors in the knowledge 
of oxygen, whose agency in most cases of combustion is un- 
questionable: that he reasoned from a known cause; they 
entirely from hypotheses and imaginary causes. We ar 
therefore by no means to distrust his explanation, because so 
many false explanations had gone before it. 
In order to show how much more confidence ought to be 
reposed in those who argue from facts than in those who ar- 
gue from hypotheses, Fontenelle, a French writer of great 
vivacity, borrows a happy illustration from the representa- 
tions of the stage. “ Let us imagine,” says he, “ all the sages 
d@ at an opera, the Pythagorases, Platos, Avis- 
totles, and all those great names which now-a-days make so 
much noise in our ears. Let us suppose that they see the 
flight of Phaeton as he is represented carried off by the winds; 
that they cannot see the cords to which he is attached; an 
that they are quite ignorant of every thing behind the scenes. 
It is a secret virtue, says one of them that carries off Phae- 
ton. Phaeton, says another, is compo «d of certain numbers, 
which cause him to ascend. A third ays, Phaeton has a 
certain affection for the top of the stage. Phaeton, says a 
fourth, is not formed to fly ; but he likes bet er to fly thun to 
leave the top of the stage empty, and a hundred other absurdi 
ties of the kind, that might have ruined the reputation of an- 
tiquity, if the reputation of antiquity for wisdom could have 
been ruined. At last come Descartes and some other mo- 
derns, who say, Phaeton ascends, because he is dr wn vy 
cords, and because a weight, more heavy than he, is descend- 
ing as a counterpoise.”* In the same manner | regard La- 
* Brown’s Lectures on Intellectual Philosophy, i, 104. 
