15. A man who is not spiritual can yet think and consequently speak rationally like a spiritual man, because man's understanding can be elevated into the light of heaven, which is truth, and can see by that light; but man's will cannot be similarly elevated into the heat of heaven, which is love, and act from that heat. Hence it is that truth and love do not make one in a man unless he is spiritual. Hence also it is that man can speak; and this also forms a distinction between man and beast. It is through this capability of the understanding to be elevated into heaven, (but not yet of the will), that man can be reformed and become spiritual; but he is first reformed and becomes spiritual when the will also is elevated. From this faculty belonging to the understanding over that of the will, a man can think, and thence speak, rationally like one who is spiritual, whatever his quality may be, even though he should be principled in evil. Nevertheless he is not rational, because the understanding does not lead the will, but the will the understanding, the latter only teaching and showing the way; as is stated in THE DOCTRINE OF THE SACRED SCRIPTURE No. 115. As long, therefore, as the will is not in heaven along with the understanding, the man is not spiritual, and consequently not rational. For when he is left to his own will, or his own love, he rejects the rational ideas of his understanding concerning God, heaven and eternal life, and in their place he adopts such ideas as agree with the love of his will, and these he calls rational. But further consideration of these matters will be seen in the treatises on Angelic Wisdom.