251. The reason why the “serpent” means all evil in general, and specifically the love of self, is that all evil has had its rise from that sensuous part of the mind, and also from that memory-knowledge [scientifico], which at first were signified by the “serpent;” and therefore it here denotes evil of every kind, and specifically the love of self, or hatred against the neighbor and the Lord, which is the same thing. As this evil or hatred was various, consisting of numerous genera and still more numerous species, it is described in the Word by various kinds of serpents, as “snakes” “cockatrices” “asps” “adders” “fiery serpents” “serpents that fly” and “that creep” and “vipers” according to the differences of the poison, which is hatred. Thus we read in Isaiah:

Rejoice not thou, whole Philistia, because the rod which smiteth thee is broken, for out of the serpent’s root shall go forth a cockatrice, and his fruit shall be a flying fire-serpent (Isaiah 14:29).The “serpent’s root” denotes that part of the mind, or that principle, which is connected with the senses and with memory-knowledge [est sensuale et scientificum]; the “cockatrice” denotes evil originating in the falsity thence derived; and the “flying fire-serpent” the cupidity that comes from the love of self. By the same Prophet also similar things are elsewhere thus described:

They hatch cockatrice’s eggs, and weave the spider’s web; he that eateth of their eggs dieth, and when it is crushed there cometh out a viper (Isaiah 59:5).

The serpent described here in Genesis is called in the Revelation the “great and red dragon” and the “old serpent” and also the “devil and satan” that “deceives the whole world” (Revelation 12:3, 9; 20:2), where, and also in other places, by the “devil” is not meant any particular devil who is prince over the others, but the whole crew of evil spirits, and evil itself.

6398. 'Dan will be a serpent on the road' means their reasoning regarding truth, since good does not as yet lead them. This is clear from the representation of 'Dan' as those guided by truth but not as yet by good, dealt with above in 6396; from the meaning of 'a serpent' as reasoning based on sensory evidence, dealt with below; and from the meaning of 'the road' as truth, dealt with in 627, 2733. Thus 'Dan is a serpent on the road' means their reasoning regarding truth, since good does not as yet lead them. The nature of that reasoning and the nature of the truth resulting from it will be stated below.

[2] The reason why 'a serpent' means reasoning based on sensory evidence is that the interiors of a person are represented in heaven by living creatures of various kinds, and therefore in the Word similar things are meant by those same creatures. A person's sensory powers have come to be represented by serpents because they are the lowest of his mental powers. Compared with other mental powers those of the senses are on the ground so to speak, crawling around there, as may also be recognized from the forms that sensory impressions adopt when they enter in, which will in the Lord's Divine mercy be dealt with elsewhere. This explains why those sensory powers have come to be represented by 'serpents', so much so that the Lord's Divine sensory perception was represented by the bronze serpent in the wilderness, 4211 (end).

[3] True shrewdness and circumspection - qualities that reveal themselves in external affairs - were also meant by 'serpents', in Matthew,

Be shrewd as serpents and simple as doves. Matthew 10:16.

But in the case of a person who is governed by his senses and is far removed from what is internal - as those people are who are guided by truth but not as yet by good - and who speaks as his senses tell him, 'a serpent' means false reasoning. This therefore is why here, where Dan is the subject, reasoning regarding truth because good does not as yet lead him is meant. In other contexts ill-will, deceitfulness, and trickery are also meant by 'serpents', though in those places they are poisonous serpents - such as vipers and the like - whose reasoning is their poison.

'A serpent' is reasoning based on sensory evidence, see 195-197.

'A serpent' is all evil in general, and evils are distinguished from one another by different kinds of serpents, 251, 254, 257.