palaces, to be clothed in silk, and to indulge in baths, ointments, and perfumes. The same is the case with those opinions of man to which he has been accustomed from his youth; he likes them, defends them, and shuns the opposite views. This is likewise one of the causes which prevent men from finding truth, and which make them cling to their habitual opinions. Such is, e.g., the case with the vulgar notions with respect to the corporeality of God, and many other metaphysical questions, as we shall explain. It is the result of long familiarity with passages of the Bible, which they are accustomed to respect and to receive as true, and the literal sense of which implies the corporeality of God and other false notions; in truth, however, these words were employed as figures and metaphors for reasons to be mentioned below. Do not imagine that what we have said of the insufficiency of our understanding and of its limited extent is an assertion founded only on the Bible; for philosophers likewise assert the same, and perfectly understand it, without having regard to any religion or opinion. It is a fact which is only doubted by those who ignore things fully proved. This chapter is intended as an introduction to the next. CHAPTER XXXII You must consider, when reading this treatise, that mental perception, because connected with matter, is subject to conditions similar to those to which physical perception is subject. That is to say, if your eye looks around, you can perceive all that is within the range of your vision; if, however, you overstrain your eye, exerting it too much by attempting to see an object which is too distant for your eye, or to examine writings or engravings too small for your sight, and forcing it to obtain a correct perception of them, you will not only weaken your sight with regard to that special object, but also for those things which you otherwise are able to perceive: your eye will have become too weak to perceive what you were able to see before you exerted yourself and exceeded the limits of your vision. The same is the case with the speculative faculties of one who devotes himself to the study of any science. If a person studies too much and exhausts his reflective powers, he will be confused, and will not be able to apprehend even that which had been within the power of his apprehension. For the powers of the body are all alike in this respect.