We must begin with First Principles. What can we know, and how may we know it? Firstly, there is an epistemological question as to how we may know anything at all. In the DesCartesian sense, we know that we exist because we are thinking about it, and so we must exist insofar as we experience our own contemplation of it. There would seem along with ourselves to be at least one entity external to our immediate experience of ourselves because we are met with thought which seems not to be originating in our own minds. Now it could be true that all of our sensory perceptions are illusions created to test our reactions or some similar purpose, but this requires that there be at least one source of intelligence external to our own experience of self, to be imposing that experience on us (though even then we can not exclude the possibility that we are merely an isolated expression within a larger mind appearing to us as this seemingly other intelligent being).
But speculation about an illusory Universe raises the question, how can we know our experience of our Universe to be real? Now, there are precisely two possibilities about the reality of our Universe as it presents itself to us. Either it is absolutely real, or it is not, for if any part of our perception of our Universe is an illusion, an impenetrable deception, then the acknowledged presence of unreality means that nothing may be logically taken as real. But we will backtrack for a moment here and concede that even if our perception of our Universe is simply an illusion being imposed upon us, it is what is being presented to us to be taken as real, and so ought to be treated as real. But in any event, absent affirmative proof of an illusory capacity of our Universe, we have no reason to assume it to be anything but real.We have two sources of information. Our senses, and our logical and mathematical contemplations. It is dubious to suggest that we may draw conclusions based on our senses alone, in part because we suffer from grave problems of scale. There are events vital to our understanding of our existence occurring at scales far too great and too small to be perceptible by man, and it must be confessed that assumptions about our Universe which fail to observe a proper awareness of these can be dismiss in the first instance. So far as our current capacity to observe informs us, we humans are approximately 43% of the way from the largest scale of observation -- that of our entire visible Universe -- to the smallest, that being the subquark.
But I submit that investigation of the nature of our Universe reveals it to be the product of an act of design. We are able to observe that we human beings are made out of a collection of interacting organs, that these organs are made out of cells, and that these cells are made out of molecules -- and indeed every tangible thing which we are able to observe or interact with is similarly made out of molecules; and these molecules have particular properties reflective of the atoms of which they are themselves made, and there is no molecule in our Universe but one made from atoms. And we are further able to observe that there are many kinds of atoms, almost all of which are created by stellar fusion and spat out of dying stars but that these kinds adhere to a strict set of rules -- which are in turn dictated by their composition of subatomic particles, and so forth down past the level of those subquarks we mentioned before.
It is a remarkable thing that at each level of substance, the material at issue is able to self-organize in accordance without the governing dynamics of our Universe (things such as the strength of gravity and the speed of light and the combination of attractive and repulsive forces between protons and electrons. I'll not belabor here the fineness of calculation needed to permit subatomic particles to form lint atoms, which form stars spitting out heavy atoms in their death throes, heavy atoms forming the complex self-replicating molecules of life, and eventually intelligent life, and eventually something even beyond that. But even this is not what I rest the proposition of design upon; for not only is our Universe fundamentally complex enough to generate this level of complexity; it is at the same time fundamentally simple enough for intelligent beings to figure out that these forces are what is at play, and to use them to invent things like light bulbs and calculators and computers and massive particle colliders.
I'll give one very specific example. We have determined by observing the light signatures of distant galaxies that our Universe is expanding at a rate consistent with origin in a single explosive expansion from a singularity having occurred approximately 13.72 billion years ago. We have observed as well that there exists a microwave background radiation in our Universe indicative of the same origin. But given sufficient time those galaxies will recede beyond detectibility and that microwave background radiation will evaporate entirely; were we not fortunate enough to develop the tools by which to measure these things before they became undetectable to us, we would neve know or have any reason to imagine the age of our Universe -- suggesting that our Universe was designed to essentially inform us of its age and origin. And we have only in the past few years acquired the ability to confirm the long-suspected existence of habitable worlds within the conceivable range of our technological reach. These worlds call to us for exploration and colonisation, perhaps an entire galaxy able to be made man's.
Now, having established (at the least) a reasonable basis for believing ours to be a Created Universe, we turn to the characteristics of our Creator. There are THREE -- and only three -- which are absolutely necessary: it must have sufficient power to supply and control the incomprehensible energy of our Universe; it must have sufficient intelligence to design the governing dynamics which result in that energy taking the increasingly complex material forms observed; and it must have sufficient rationality to create a Universe which operates rationally, building itself towards these evident ends.
And let me be absolutely clear here, if a theological model exists by which these three assumptions suffice to account for all of the observations man is able to make, then no other assumptions may logically be added, no matter how strongly they might serve our sense of importance. This is as simple a proposition as stating that footprints in the sand most likely reveal that a person walked there. If a person capable of walking sufficiently explains what is observed, then there is no basis for assuming that the leaver of the footprints was able to fly as well, or that it possessed any particular set of loves or hates.
And here we come to the theological theory of Pandeism. A Creator with sufficient power and intelligence to create by becoming, and rationally motivated to do so by the desire to obtain the experiential knowledge of existing as our Universe, a Universe inevitably containing intelligent life which travels amongst the many habitable worlds provided for it.
Now, the acid test, the sixty four million dollar question. Is there anything in our Universe which can not be accounted for by this model? Theists tend to point to their respective scriptures and the events described in them, to reports of faith affirming miracles or visions or the like, and to emotional appeals begging that absent an intervening deity, wrongs will not be punished. But because there are many contradictory accounts of this sort, and because there are and have been many millions of people who are isolated from ever hearing about any given theistic path, additional assumptions must be piled on to explain this, usually involving the additional creation of contingent evil spirits, or of past or future lives, or of varying degrees of life after death.
But if the assumptions underlying the pandeistic model are correct, then we are all fragments of an incomprehensibly powerful and intelligent Creator, and so all of the things which theists point to -- scripture, miracles, revelations, prophecies, spiritual emotions, visions, dreams, egrigori, efficacious prayer, all of these, are simply expressions of the power of our Creator as touched by and filtered by our limited (if sometimes spiritually talented) human minds. I don't doubt that theists tire of having this pointed out to them as much as I tire of explaining it anew each time, but the principle remains that every theistic explanation inherently requires fatally more assumptions to account for the same proof (and most leave substantial proof unaccounted for altogether).