Yet Descartes has defined what he means by innate ideas with so much precision, that misconception ought to have been impossible. He says that, when he speaks of an idea being "innate," he means that it exists potentially in the mind, before it is actually called into existence by whatever is its appropriate exciting cause. "I have never either thought or said," he writes, "that the mind has any need of innate ideas [_idees naturelles_] which are anything distinct from its faculty of thinking. But it is true that observing that there are certain thoughts which arise neither from external objects nor from the determination of my will, but only from my faculty of thinking; in order to mark the difference between the ideas or the notions which are the forms of these thoughts, and to distinguish them from the others, which may be called extraneous or voluntary, I have called them innate. But I have used this term in the same sense as when we say that generosity is innate in certain families; or that certain maladies, such as gout or gravel, are innate in others; not that children born in these families are troubled with such diseases in their mother's womb; but because they are born with the disposition or the faculty of contracting them."[22] His troublesome disciple, Regius, having asserted that all our ideas come from observation or tradition, Descartes remarks:-- "So thoroughly erroneous is this assertion, that whoever has a proper comprehension of the action of our senses, and understands precisely the nature of that which is transmitted by them to our thinking faculty, will rather affirm that no ideas of things, such as are formed in thought, are brought to us by the senses, so that there is nothing in our ideas which is other than innate in the mind (_naturel a l'esprit_), or in the faculty of thinking, if only certain circumstances are excepted, which belong only to experience. For example, it is experience alone which causes us to judge that such and such ideas, now present in our minds, are related to certain things which are external to us; not in truth, that they have been sent into our mind by these things, such as they are, by the organs of the senses; but because these organs have transmitted something which has occasioned the mind, in virtue of its innate power, to form them at this time rather than at another....