One of the more striking arguments (if you will pardon the pun) for the existence of a Creator-god is what is popularly known as the divine watchmaker argument. The argument suggests that things which are the product of an intelligent designer's design are immediately apparent to us by their complexity and intricacy.
It was British religionist William Paley, who perhaps most famously enunciated this contention when he wrote in his Natural Theology: In crossing a heath, suppose I pitched my foot against a stone, and were asked how the stone came to be there; I might possibly answer, that, for anything I knew to the contrary, it had lain there forever: nor would it perhaps be very easy to show the absurdity of this answer. But suppose I had found a watch upon the ground, and it should be inquired how the watch happened to be in that place; I should hardly think of the answer I had before given, that for anything I knew, the watch might have always been there.Naturally, there remains (if you will pardon another pun) some grease in the gears of this argument -- for it seems to suppose that the pocket watch itself sprung fully-formed from the mind of man, needing and having neither antecedent technology nor a chain of ancestry for the men who invented it (and observe that the pocket watch is the technology of choice for this illustration because, naturally, the evolution of the wristwatch was yet incipient). In Paley's day, then, startling a conception as it may be, the pocket watch likely represented the very height of peacetime portable technological advancement -- and, indeed, more modern variations of the argument have substituted things such as 747 airliners and cellular phones (both of which by no small coincidence necessarily have time-keeping devices built into them). And yet, the very first 'pocket watch,' assembled at some early point in the 1510s, was necessarily made from some simple parts which had been made for only passingly similar purpose, or even for some other purposes entirely, but which were loosely and handily adapted for use in making that first pocket watch. Nor would it be correct to assume that the very first attempt to make a pocket watch was a complete success; surely it may have worked well enough to draw a few oohs and aahs, but as surely it was a primitive thing when put next to its more advanced descendents.
In fact, the earliest handily portable timekeeping devices which might be called 'pocket watches,' born in the early Sixteenth Century, were relatively heavy brass boxes several inches across, with a single hand -- an hour hand. Mechanisms able to accurately reflect smaller increments had not yet evolved. And even that hour hand didn't rightly tell the hours, typically tending to be off by several of them per day. Metal grillwork, instead of glass, covered the face, and the whole thing was combined by tapered pins and wedges, as screws usable for this purpose had not yet evolved either. Though they needed twice-daily winding to be kept running at all, they were as a practical matter useless as timekeeping devices, impossibly innacurate and inconsistent. Their use was strictly ornamental, as baubles for show.
But the passage of time and generations of watchmakers developing new innovations, incorporating some and discarding others as obsolete or unhelpful, brought about a gradual and continual advance. Smaller and smaller gears shrank the whole of the thing; more finely tuned springs improved accuracy until it became feasible to add another hand to count off minutes. Lighter and more durable materials were found or innovated, the grillwork was replaced with a glass face. Eventually -- in the far future even from Paley's perspective -- inventions were added ranging from the second hand and a little window displaying the date, to the quartz crystal to keep time, to the watch battery and the digital display.
But were we to come upon even an Eighteenth Century pocket watch on the heath, though we might in an instant recognize it as the product of an intelligent craftsman's hand, we would in the same instant be as well assured that the watch was not produced by a person who had himself never studied watchmaking or some analogous art, nor seen or interacted with a pocket watch. Nor would we credibly assume that the only possible explanation for the existence of the pocket watch on the heath was that it was plopped into existence from nothing by an all-powerful genie who happens, for the sake of arbitrariness, to impose punishment on all people who eat grapes and wine in the same meal, or who have sex with others of a disfavored tribe.
Nor would we be justified in imagining any capacities for the watchmaker other than that he was physically and mentally up to the task of making this one watch, and -- possibly most intriguingly for this analogy -- that he had been taught the particulars of how to make that watch by someone initially more learned on the subject than himself, though the advance of knowledge necessitates that with the passage of generations, some future craftsman would indeed exceed their teachers and improve the craft itself. And so, if a pocket watch implies a watchmaker, it at the same time implies a string of predecessors to the watchmaker, each of whom taught the next and likely improved on the craft itself.
Nor, again, does the finding of the watch demonstrate that the ability to manufacture pocket watches has existed with man, the designer, since time immemorial. Even the hundred most able and intelligent men amongst the Ancients of Greece or Rome or the Dynasties of China would have been unable to build such a device. To the contrary, man began with no way to estimate time but for the following of the sun and moon, first with eyes alone, then with sundials and other stationary devices which caught and distributed their shadows. Then came hourglasses, water clocks, and candle clocks (which measured time by the stable melting time of candles of certain lengths), and finally, only after metallurgy and the consequent discovery of the spring, the true clockwork-mechanism time-telling devices. And even these took countless models, countless small improvements, occasional combinations of innovations, to go from nothing to the modern clock over a few thousand years -- an eyeblink in the vaster geological time scales over which the biological form of evolution occurs.
So, when someone proposes finding a pocketwatch on the heath and wonders how it got there, the accurate response is that it came from ancestors which sprang by unbidden coincidence from the elements, and evolved.