Teleological argument: When you find a watch in the sand, you infer that it is designed, even if you do not see the designer, because it is complex, has a definite purpose, and could not have come to be through any known non-intelligent causes. Therefore, when we observe a complex, purposeful universe which could not have come to be through any known non-intelligent cause, it is reasonable to infer the existence of a designer, aka God.
This is related to the anthropic principle, which is sometimes misused by atheists such as Richard Dawkins. The fact that so many details had to be just so, including physical constants, to allow us to be here, argues for an intelligent designer.
Although they were not the first to suggest the idea, three separate versions of the Anthropic Principle were proposed by Barrow & Tipler (1986); these versions come in Weak, Strong and Final forms. ...
The Strong Anthropic Principle
In this version of the Principle, Barrow & Tipler suggest that regardless of whether or not we are here to observe the fact, the Universe must (by necessity) have those properties which allow life to develop within it at some stage in its history.
In other words, in this principle, it is no coincidence that we are here; the Universe is expressly configured so as to enable and encourage the prospects of our existence.
The Final Anthropic Principle
In the most extreme version of the principle, Barrow & Tipler suggest that intelligent life (or something akin to it) is a necessary feature of the universe, and once it is created it can never be become extinct.
This version of the principle seems almost to imply that the sole purpose of the Universe is to create & sustain intelligent life; not only are the values of constants arranged to do this, but there seems almost to be some unseen force driving the Universe towards its goal.