I haven’t heard anyone say specifically that nature caused itself, in so many words,(other than the Hawking axiom about the laws of gravity causing the universe), but that is the question begged by any assertion that God doesn’t exist. Anyone who maintains that nature and natural causes are the beginning and the end of all reality is begging that question: did nature cause itself?
Perhaps the greatest obstacle to the assertion that nothing supernatural exists is the Big Bang. The Big Bang is accepted science. The evidence is very compelling, though it wasn’t received well when it was first postulated. The thought that the universe was not eternal and had a beginning was thought to be “repugnant” and to “betray the very foundations of science”.
This is because a beginning to the universe suggests that the universe had a Beginner. The initial reluctance to accept the Big Bang has long ago changed, however, as the evidence has accumulated. Stephen Hawking proved it mathematically, but struggled with the implications of it the rest of his life. Stephen Hawking says, “Almost everyone now believes that the universe, and time itself, had a beginning at the Big Bang.” Hawking is an atheist (or agnostic) and doesn’t believe that the beginning proves a Beginner. He developed a multiple universe hypothesis (a multiverse) in which anything can and does happen to attempt to avoid the implications of a universe with a beginning.
Of course, that just begs the question further. If he is right (there is a multiverse), where did it come from? Alexander Vilenkin says of the Big Bang,
“With the proof now in place, cosmologists can no longer hide behind the possibility of a past eternal universe. There is now no escape. They have to face the problem of a cosmic beginning.”
Vilenkin also believes in the multiverse theory, but he doesn’t (directly) dodge the ultimate issue. He concedes that all the universes together, no matter how many there may be, require an absolute beginning.
The implication is this: If space, time and matter had a beginning, than the cause of space, time and matter must be outside of and other than space, time and matter. In other words, the cause of space, time and matter must be spaceless, timeless and immaterial. The spaceless, timeless and immaterial cause of the universe is the Beginner. An absolute beginning points to an Absolute Beginner.
Not only does science point back to the beginning of the universe, some scientists say that science points back to the Bible. Robert Jastrow, founder of the Goddard Institute of Space Studies at NASA, wrote a book in 1978 called God and the Astronomers. Though he claims to be an agnostic, he says,
“[A]stronomical evidence leads to a biblical view of the origin of the world…. The essential element of the astronomical and biblical accounts of Genesis is the same.”
During a subsequent interview, Jastrow said,
“Astronomers now find they have painted themselves into a corner because they have proven, by their own methods, that the world began abruptly in an act of creation to which you can trace the seeds of every star, every planet, every living thing in this cosmos and on the earth.… That there are what I or anyone would call supernatural forces at work is now, I think, a scientifically proven fact.”
This isn’t what many in the scientific community wanted to hear, but it only makes sense. Nature couldn’t have created the universe because that would require nature to create itself.
Even if that circular logic made any sense, science shows that there was no nature before the Big Bang! The natural world as we know it came into existence at the Big Bang.
Nature was the effect; it can’t be the cause. Nature cannot be the cause of its own effect.
While many people continue to assume that nature has a natural cause, that position makes no logical sense. Something beyond nature must have created nature and caused it to exist. That transcendent cause, by definition, must be something super (beyond) natural.
Scientists, like Vilenkin, who is often cited for his statement about an absolute beginning, still won’t concede a Beginner. Jastrow provides an introspective look at this phenomenon, being a scientific “insider” himself. He finds that the reactions have “a strange ring of feeling and emotion” that should be noted for their antithesis to a purely rational, scientific ideal.
Jastrow admits “a kind of religion in science” that possesses the scientist with “the sense of universal causation” that is “violated by the discovery that the world had a beginning under conditions in which the known laws of physics are not valid and as a product of forces or circumstances we cannot discover.” Rather than be “traumatized” by the implications, some scientists simply ignore them.
Jastrow calls this a refusal to speculate. While theologians are eager to say, “I told you so” when scientific discoveries confirm naturalistic expectations, many scientists will not speculate when the discoveries defy natural explanation.
The scientific community has defined science to exclude the possibility of super natural explanations. But some go further than that: they assert that nothing exists other than the natural world (or worlds), and so they avoid any speculation (or possibility of speculation) beyond the boundaries where science (as it is defined) can go.
But the question remains: did nature cause itself? Did the universe give birth to itself?
The leading scientific answers (including the multiverse idea) dodge that ultimate question. The multiverse hypothesis substitutes one assertion that cannot be proven by science (a multiverse) for another (God).
If other universes exist, where did they come from? And, then, we are back to begging the question whether nature caused itself.
 WHERE SCIENCE ENDS AND THEOLOGY BEGINS, by Robert Jastrow published in Bio-Orthodoxy June 17, 2014, http://www.bio-orthodoxy.com/2014/06/robert-jastrow-on-limits-of-science.html.
 THE NATURE OF SPACE AND TIME by Stephen Hawking and Roger Penrose, Princeton University Press, p. 20.
 MANY WORLDS IN ONE: The Search for Other Universes by Alexander Vilenkin, Hill and Wang; 1st edition (June 27, 2006).
 To be fair, Vilenkin is not as dogmatic about an absolute beginning as this quotation appears to make him. In an interview with an Atheist blogger he admitted: “[I]f someone asks me whether or not the theorem I proved with Borde and Guth implies that the universe had a beginning, I would say that the short answer is ‘yes’. If you are willing to get into subtleties, then the answer is ‘No, but…’ So, there are ways to get around having a beginning, but then you are forced to have something nearly as special as a beginning.” And Vilenkin, himself, does not concede that his discoveries lead inevitably to God. (See https://debunkingwlc.wordpress.com/2010/07/14/borde-guth-vilenkin/)
 GOD AND THE ASTRONOMERS by Robert Jastrow, New York and London, W. W. Norton, 1978, p. 14
 “A SCIENTIST CAUGHT BETWEEN TWO FAITHS: INTERVIEW WITH ROBERT JASTROW,” Christianity Today, August 6, 1982, PP. 15, 18.
 WHERE SCIENCE ENDS AND THEOLOGY BEGINS, quoting Robert Jastrow, The Enchanted Loom: Mind in the Universe, (1981), p. 19