It need hardly be explained that energy cannot exist independently of matter; and that the law of the persistence of matter is necessary for the existence of the law of persistence of force. [Sidenote: Universal intelligence, comparable to universal energy is indestructible, according to Joseph Smith.] Joseph Smith was not a scientist; and he made no pretense of solving the scientific questions of this day. The discussion relative to the convertibility of various forms of energy was in all probability not known to him. Still, in his writings is found a doctrine which in all respects resembles that of the conservation of energy. Joseph Smith taught, and the Church now teaches, that all space is filled with a subtle, though material substance of wonderful properties, by which all natural phenomena are controlled. This substance is known as the Holy Spirit. Its most important characteristic is intelligence. "Its inherent properties embrace all the attributes of intelligence."[A] The property of intelligence is to the Holy Spirit what energy is to the gross material of our senses. [Footnote A: Key to Theology, P. P. Pratt, 5th ed., p. 40.] In one of the generally accepted works of the Church, the energy of nature is actually said to be the workings of the Holy Spirit. The passage reads as follows: "Man observes a universal energy in nature--organization and disorganization succeed each other--the thunders roll through the heavens; the earth trembles and becomes broken by earthquakes; fires consume cities and forests; the waters accumulate, flow over their usual bounds, and cause destruction of life and property; the worlds perform their revolutions in space with a velocity and power incomprehensible to man, and he, covered with a veil of darkness, calls this universal energy, God, when it is the workings of his Spirit, the obedient agent of his power, the wonder-working and life-giving principle in all nature."[A] [Footnote A: Compendium, Richards and Little, 3rd ed., p. 150.] In short, the writings of the Church clearly indicate that the various forces of nature, the energy of nature, are only manifestations of the great, pervading force of intelligence. We do not understand the real nature of intelligence any better than we understand the true nature of energy. We only know that by energy or intelligence gross matter is brought within reach of our senses. Intelligence or energy was declared by Joseph Smith in May, 1833, to be eternal: "Intelligence, or the light of truth, was not created or made, neither indeed can be."[A] In the sermon already referred to the Prophet said, "The intelligence of spirits had no beginning, neither will it have an end." [Footnote A: Doctrine and Covenants, 93:29.] These quotations, and many others to which attention might be called, show clearly that Joseph Smith taught the doctrine that the energy of the universe can in nowise be increased or diminished, though, it may manifest itself in various forms.