Again: while Scepticism is rampant, and some are endeavouring to bring back the Pagan notions of ancient nations, to galvanize into new life the corrupt imbecilities of the past, men of science are making assertions and assumptions of the boldest, if not of the wildest nature. One such recently maintained the following proposition:--“Taking our earth, we _know_ that millions of years have passed since she began to be peopled.” Now, the maintainer of this assertion notoriously holds some peculiar theories about the means by which the solar system (and consequently other systems) was made, or rather grew. These theories, in some of their details, are or may be founded upon certain more or less well-ascertained facts. But when he uses the term “know,” we are bold to point out that such an assertion rests on mere assumption.[7] We need facts,--facts which could stand the careful investigation of persons skilled in taking and measuring evidence; and secondly, we require to be reasonably convinced that no other possible explanation of a difficulty be forthcoming, except that on which his assumption is founded and his inevitable conclusion (as he regards it) deduced. But how often with scientific people the phrase “We know” stands for “This is our theory,” or rather “This is our _present_ theory;” for scientific theories change very frequently; and points which have been most dogmatically laid down at one period have been with equal dogmatism condemned and repudiated at another, by those who apparently strain every nerve and exercise every gift bestowed upon them, to deny and cast out the Supernatural from amongst mankind. From the introduction to a volume of great interest (“The Maxims and Examples of the Saints”), the following extract is taken, both because of its inherent truth, and also because the Christian instinct in defence of the Supernatural is so prominently and forcibly expressed in every line. Mr. de Lisle’s words stand thus:--