How do Latter-day Saints respond to William Lane Craig's philosophical objections to the Mormon view of creation?

There is no problem with infinite descent. Space is infinite. Eternity extends infinitely in both directions. What would be problematic is if you were to find a child having no parents. No such critter exists. The doctrine of non-descent is absurd because it requires impotent nothingness to be fertile; descent only occurs in the same manner as God ordained that it should be on this Earth. The only rational explanation is that only self-existent beings can be fertile. "Nothingness" cannot be fertile. Darwinism expects people to be stupid by telling them that everything was created by nothing, and demanding that they believe it. We do not hold that view. The reality of infinite descent and eternal existence is infinitely more rational than anything ex nihilo. This is true no matter which direction particles or galaxies appear to be moving in the present snapshot. What I have heard renowned scientists claim regarding so-called black holes and the posit of the alleged "big bang" is that "the laws of physics cease to apply" in such situations. They take us all for morons by so saying, and admit that they have no explaining power because they are not honest. "From such turn away". There is no such thing as a condition in which eternal laws cease to apply. All true laws that govern the universe are eternal. To fudge on this point is to admit oneself to be Satan's servant.

The archetypal absurdity is the non-conservation of matter or non-conservation of intelligence (or in other words, being). The conservation laws of physics, which we can strengthen with these further rational arguments, are eternal. Neither matter nor intelligence (non-fungible identity and consciousness) can be created or destroyed.

What is further worth remarking on is the fact that all ex nihilo arguments tend to promote "ad nihilo" worldviews, or in other words, nihilism. One cannot believe that we were created from nothing without also believing that we are destined for nothing. Every physical thing that had a beginning will have an end. Nothing that has no beginning will ever end. This is sound logic.

The doctrine of annihilation is false, the same as the doctrine of nonexistence spawning existence. Wm. Craig's logic is flawed in that regard.

We are the children of God, therefore we are co-eternal with God. To say otherwise is to blaspheme against God, and rebel against His plan. We never had a beginning. Neither did He. We shall have no end. This is sound logic.

When revelation and human philosophy clash, it's not philosophy that wins as far as LDS are concerned.

Colossians 2:8

Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world, and not after Christ.

To begin with, Dr. Craig's presentation of what LDS believe doesn't seem to be quite accurate. It is unfortunately not uncommon among those who would minister to LDS to set up philosophical strawmen which they may then demolish.

First, if the LDS believe that God has a tangible body of flesh and bone, one might ask, what kind of flesh, what kind of bone, composed of what kind of matter? What kind of body did Jesus have after His resurrection, that he could be handled and felt, but appear and disappear from closed rooms and ascend into heaven? One may legitimately question whether modern cosmology has anything to say about beings on such a different plane of existence. According to D&C 131:7, all spirit is matter, although it is more fine or purer and is inaccessible to our ordinary senses and instruments. Cosmology has nothing to say about that, either.

Second, while LDS may believe in the existence of other gods, they do not worship them, so "crass polytheism" is a rather pejorative description of LDS belief.

Third, LDS would claim that revelation from God (as in D&C 93:33) is superior to any philosophical or even scientific argument. Scientific understanding is always subject to revision, or if it is sufficiently speculative, complete reversal based on new evidence and new discoveries. Any philosophical argument can be debated or challenged.

And fourth, what revelation we do have is insufficient to resolve any philosophical conundrum (such as the infinite regress) that may be propounded. "We don't know, it hasn't been revealed yet, and it's pointless to speculate without evidence." Indeed, LDS belief (as per D&C 101: 32-34) is that Christ will reveal such things when He comes.

My response comes in two parts:

1. Creation ex-nihilo (in a separate answer for readability)
2. Theosis & the Nature of God (this answer)

(Sorry, no money-back guarantee for those anticipating a 3-part answer)

Theosis

Depperm has written an excellent answer describing the Biblical basis for theosis.

I'll add 4 non-Biblical quotes as well:

Irenaeus of Lyons:

our Lord Jesus Christ, the Word of God, of His boundless love, became what we are that He might make us what He Himself is (Against Heresies Book 5, Preface)

Clement of Alexandria:

the Word of God became a man so that you might learn from a man how to become a god (Exhortation to the Greeks, 1)

Augustine:

But he himself that justifies also deifies, for by justifying he makes sons of God. ‘For he has given them power to become the sons of God’. If then we have been made sons of god, we have also been made gods.(On the Psalms 50.2)

CS Lewis:

It is a serious thing to live in a society of possible gods and goddesses, to remember that the dullest and most uninteresting person you talk to may one day be a creature which, if you saw it now, you would be strongly tempted to worship (The Weight of Glory and Other Addresses, revised edition, p.18)

Polytheism

I'll offer the following distinction.

In a polytheistic world, the ancient Greeks (for example) had to worry about pleasing Zeus, and Athena, and Poseidon, all without upsetting Hades too much, and so on. Their deities were in conflict and would (in ancient Greek lore) pit humans against one another. Polytheists found themselves casting their worship in multiple directions.

In a monotheistic world, worship goes in one direction. I suggest that one cannot truly worship the Father without worshipping the Son, and one cannot please One with pleasing the Other. To Latter-day Saints, the Father, Son, and Holy Ghost are 3 distinct beings, and these members of the Godhead have perfect unity in purpose and plan. Our worship goes in one and only one direction.

Summary

We believe very literally Paul's statement "And if children, then heirs; heirs of God, and joint-heirs with Christ" (Romans 16:9)

Theologian and former Brigham Young University Dean of Religion Robert Millet has written:

Latter-day Saints do not believe that human beings will ever be independent of God, or that they will ever cease to be subordinate to God. They believe that to become as God means to overcome the world through the atonement of Jesus Christ (see 1 John 5:4—5; Revelation 2:7, 11). Thus the faithful become heirs of God and joint heirs with Christ and will inherit all things just as Christ inherits all things...There are no limitations on these scriptural declarations; those who become as God shall inherit all things (see here p.15)

The Church's statement on the topic can be found in the essay: Becoming Like God.

The nature of God

The Father has a body of flesh and bones as tangible as man’s; the Son also; but the Holy Ghost has not a body of flesh and bones, but is a personage of Spirit. Were it not so, the Holy Ghost could not dwell in us. (Doctrine & Covenants 130:22)

Much speculation has been pursued regarding beliefs on God's past. I consider this speculation futile because God has said so little about it.

The most direct statements that have been revealed on the matter can be found in Joseph Smith's King Follett discourse.

Two summary quotes from this discourse are worth repeating here, in an effort to emphasize what Joseph Smith did say, and what he did not say:

God himself was once as we are now, and is an exalted man, and sits enthroned in yonder heavens!

These ideas are incomprehensible to some, but they are simple. It is the first principle of the gospel to know for a certainty the character of God, and to know that we may converse with Him as one man converses with another, and that He was once a man like us; yea, that God himself, the Father of us all, dwelt on an earth, the same as Jesus Christ Himself did;

--

A summary of church teachings on a Mother in Heaven can be found here.

Eliza R. Snow, former general president of the church's Relief Society, included the following in a poem (full text available here) now published in the church's hymnal:

I had learned to call thee Father, Through thy Spirit from on high,

But until the key of knowledge Was restored, I knew not why.

In the heavens are parents single? No, the thought makes reason stare!

Truth is reason, truth eternal Tells me I've a mother there.

--

Church teachings are consistent with the possibility of more than one universe, but God has elected to tell us virtually nothing about any other universe (see Moses 1:35). There is no church doctrine, as Dr. Craig mused, of antecedent deities squished into this universe now or at any time in the past.

Further Reading:

• Joseph Smith & the Recovery of Eternal Man by Robert Millet (video & transcript)
• What do Latter-day Saints mean when they say that God was once a man? by Robert Millet & Noel Reynolds (here pp. 19-21, including a discussion of the concept "everlasting to everlasting")

--

Conclusion

From 1 Cor. 8:

5 For though there be that are called gods, whether in heaven or in earth, (as there be gods many, and lords many,)

6 But to us there is but one God, the Father, of whom are all things, and we in him; and one Lord Jesus Christ

Latter-day Saints believe that God offers limitless opportunities to His children.

This is explored further in this video on my channel.

Disclaimer - my comments are the product of my own study and do not constitute official statements by The Church of Jesus Christ of Latter-day Saints