The history of the word matter teaches us then that speech, whose sole duty it is to introduce light into our minds, admits error also as long as we are ignorant of the original meaning of words: matter, whilst it was the solid wood of a tree and wood for building, became for those who had coined the word a fit object for perception and conception; later, others, differently constituted, saw in it a word “which contains to every man exactly what he has found in it or added to it.”[134] There are many words whose transformations we are able to follow from one language to another, but, on the other hand, there are others whose history it is not possible to know with exactness, owing to the many revolutions, the many breaks and pauses which here and there have destroyed and scattered the links; but the science of language progresses, and those who study it look forward to the day when its foundations will be placed on philosophical bases. Many of the false ideas we have conceived of words are no doubt owing to the translations we read of books. When we first begin the study of a new language the task appears a simple one, the dictionary supplies us with the equivalent words and the grammar with the correct forms; but the further we advance the less we are satisfied; the difficulties of finding expressions which content us increase; words are too abundant, or too scarce; our conceptions are invaded by ideas of complete disparity; and we seem to be entering an unknown land, because new effects of light and shade have lent a novel character to the country. A translation is therefore at best but an effort to bring together thoughts which were designed to remain always apart. If in our modern languages certain words necessarily change their meaning during the course of three or four centuries, ancient languages are under the same necessity in an infinitely greater degree.