6400. 'Biting the horse's heels' means false notions received from the lowest natural level. This is clear from the meaning of 'biting' as clinging to and thereby causing harm, and from the meaning of 'the horse's heels' as false notions received from the lowest natural level; for 'the heel' is the lowest and bodily part of the natural, 259, 4938-4952. While 'horse' is the understanding part of the mind, 2761, 2762, 3217, 5321, 6125. 'Horse' here means false notions because the lowest natural level of the understanding, which is that of the senses, is meant. People who are guided by truth but not as yet by good are subject to false notions received from that lowest natural level. This may be recognized from the consideration that truth is not in any light unless good resides with it or exists within it. For good is like a flame radiating light, and when that good meets some truth it not only throws light on it but also draws it into that radiating light, towards itself. People therefore who are guided by truth but not as yet by good are in a kind of gloom and darkness, because truth possesses no light at all of its own, and the light which those people receive from good is as feeble as light which fades away. When such people therefore think and engage in reasoning about truth, and from truth about good, they are like those who see apparitions in the darkness and believe them to be real bodies. Or they are like people who in the gloom see streaks on a wall and whose imagination leads them to make some shape out of them, either of a human being or of some other living creature. But when daylight comes it is seen that they are merely streaks without any such shape. It is much the same with the truths residing with them; for they see as truths what are not truths, which ought rather to be likened to apparitions or streaks on the wall. What is more, people of this kind - those who have been guided by some truth from the Word but not by any good - have been the source of all the heresies that have arisen within the Church; for heretical belief has been seen by them to be altogether the truth. So too with falsities within the Church. Those who have disseminated them have not been guided by good, as may be recognized from the consideration that they cast the good of charity far behind the truth of faith and as a consequence have for the most part invented ideas which are in no way compatible with the good of charity.
[2] Since it is said that those who are guided by truth but not as yet by good use false notions received from the lowest natural level to reason about truth and about good, let something also be said about what false notions are. Take for example a person's life after death. People subject to false notions received from lowest nature, such as those who are guided by truth but not as yet by good, do not believe that any part of a person except his body has life, or that a person can possibly rise again when he dies unless he gets back his body. If these people are told that the interior man is the one who has life within the body and who is raised up by the Lord when the body dies, and that this interior man has a body like those that spirits or angels have, and that like a person in the world he can see, hear, talk, mix with others, and seem to himself to be altogether a person, they cannot grasp any of it. False notions received from the lowest natural level cause them to believe that such things cannot be true.
[3] The chief reason why they do not believe them to be true is that they cannot see those things with their physical eyes. When such people think about the spirit or soul, the only idea they can have of it is that it is like things the eye cannot see in the natural world. Consequently they consider it to be either something breath-like, or else something air-like, ether-like, or flame-like, or - according to some - something purely thought-like, which possesses scarcely any vitality until it is joined again to the body. These people think the way they do because to them everything of an interior nature is gloom and darkness and only those of an external nature are in light. This shows how easily such people can fall into error; for if they limit their thought to the body and how it will be reassembled, to the destruction of the world and the fact that it has been awaited in vain for so many centuries, to animals and the fact that they have life not unlike man's life, or to the fact that no dead persons reappear and declare their state of life, they easily recede - when they think of these and other such things - from belief in resurrection, as they do from many other matters of belief. The reason they recede from that belief is that they are not guided by good and do not through good see in the light. Such being their condition it also says, 'And its rider will fall backwards; I wait for Your salvation, O Jehovah', meaning a receding from [the truth] unless the Lord comes to their aid.
