proceeded to seek it by studying such notions." In his next chapter, Dr. Whewell has so well illustrated and exemplified this error, that I shall take the liberty of quoting him at some length. "The propensity to seek for principles in the common usages of language may be discerned at a very early period. Thus we have an example of it in a saying which is reported of Thales, the founder of Greek philosophy. When he was asked, 'What is the _greatest_ thing?' he replied '_Place_; for all other things are _in_ the world, but the world is _in_ it.' In Aristotle we have the consummation of this mode of speculation. The usual point from which he starts in his inquiries is, that _we say_ thus or thus in common language. Thus, when he has to discuss the question whether there be, in any part of the universe, a void, or space in which there is nothing, he inquires first in how many senses we say that one thing is _in_ another. He enumerates many of these; we say the part is in the whole, as the finger is _in_ the hand; again we say, the species is in the genus, as man is included _in_ animal; again, the government of Greece is _in_ the king; and various other senses are described and exemplified, but of all these _the most proper_ is when we say a thing is _in_ a vessel, and generally _in place_. He next examines what _place_ is, and comes to this conclusion, that 'if about a body there be another body including it, it is in place, and if not, not.' A body moves when it changes its place; but he adds, that if water be in a vessel, the vessel being at rest, the parts of the water may still move, for they are included by each other; so that while the whole does not change its place, the parts may change their place in a circular order. Proceeding then to the question of a _void_, he as usual examines the different senses in which the term is used, and adopts as the most proper, _place without matter_: with no useful result. "Again, in a question concerning mechanical action, he says, 'When a man moves a stone by pushing it with a stick, _we say_ both that the man moves the stone, and that the stick moves the stone, but the latter _more properly_.' "Again, we find the Greek philosophers applying themselves to extract their dogmas from the most general and abstract notions which they could detect; for example, from the conception of the Universe as One or as Many things. They tried to determine how far we may, or must, combine with these conceptions that of a whole, of parts, of number, of limits, of place, of beginning or end, of full or void, of rest, or motion, of cause and effect, and the like. The analysis of such conceptions with such a view, occupies, for instance, almost the whole of Aristotle's Treatise on the Heavens."