Latter-day Saints affirm the existence of spirit matter. Doctrine & Covenants 131:7–8 reads:

All spirit is matter, but it is more fine or pure, and can only be discerned by purer eyes; We cannot see it; but when our bodies are purified we shall see that it is all matter.

It is further confirmed in the Doctrine & Covenants that matter is eternal (Doctrine & Covenants 93:33). There is much that Latter-day Saints and others interested have yet to learn about the nature and operation of spirit matter, but one thing that is certain is that this spirit matter played a role in our creation.

Latter-day Saints know that before we came to this life, we lived in the presence of God the Father (see #58 A GRAND COUNCIL IN HEAVEN, #71 PREMORTAL LIFE). Latter-day Saints have taken different positions over time of whether or not our spirits were created at one point or not. Joseph Smith seems to have publicly taken the position that our spirits were never created.¹⁶⁷ Privately he seems to have been more open to the possibility that they were.¹⁶⁸ His revelations, and most especially the Book of Moses, seem to portray real spirits being created at some point. Moses there was granted a vision by God and “beheld the world and the ends thereof, and all the children of men which are, and which were created” (Moses 1:8, emphasis added). In chapter 3, the Lord says that “I, the Lord God, created all things, of which I have spoken, spiritually before they were naturally upon the face of the earth. For I, the Lord God, had not caused it to rain upon the face of the earth. And I, the Lord God, had created all the children of men; and not yet a man to till the ground; for in heaven created I them” (Moses 3:5). Further, Cain in Moses 5:24 is told that “thou wast also before the world.”

The dominant understanding of our pre-earth life among Church leaders and members today seems to be that we had an intelligence. This intelligence has always existed and will always exist. That intelligence at some point was clothed with a spirit body through some union formed by our Heavenly Father and Heavenly Mother (see #59 A MOTHER IN HEAVEN).

That a form of matter has always existed is congruent with current scientific understandings of the universe including the 1st Law of Thermodynamics which states that energy cannot be created or destroyed. Rather, it can simply go from one form to another form. In order to account for the eternality of our spirits and the universe, Latter-day Saint theologian and philosopher Blake Ostler has argued that we should seek to confirm a form of inflationary cosmology, about which he explains and defends more.

This understanding is unique and exclusive to the Latter Day Saints Movement.