6190. Since influx is the subject under discussion and the word is used so frequently, a preliminary statement must be made as to what influx is. There is no better way to show what is meant by spiritual influx than by comparison with natural kinds of influx that take place and reveal themselves in the world. There is for example the flow of heat from the sun into all earthly objects and all its variations that are determined by the seasons of the year and climates of the earth. Then there is the flow of light into those same objects and all its variations that are determined by the times of day as well as seasons of the year, further varied also by climates. It can be seen from the fact that the flow of heat from the sun into all earthly objects gives rise to plant-life, and that the flow of light into the same objects assists that plant-life and also produces different colours and beautiful sights. What influx is may be recognized in a similar way from the flow of that same heat into the surface-area of our bodies, and also of light into the eye. Likewise from the flow of sound into the ear, and from other inflowings like it, one may understand what the influx of life from the Lord is. He is the Sun of heaven and the Source of heaven's heat, which is the good of love, and the Source of heaven's light, which is the truth of faith. One can also plainly feel the inflow of them, for heavenly heat, which is love, produces the vital heat that exists in a person, while heavenly light, which is faith, produces his power of understanding, since the truth of faith, which goes forth from the Lord, gives his understanding light. But there is much variation to both these kinds of influx, for the exact nature of them is determined by the ways people receive them.