Possibility 1: Blind Chance
This is the typical answer given by scientific academia in regard to what controls evolution. The theory is that random events such as cosmic rays or DNA copying mistakes cause chance mutations in the DNA stored in cells of an organism. This creates a variation in characteristics in a species, and those variations that have more survival value end up getting reproduced more, because of natural selection and survival of the fittest.
I do not exclude the possibility, but there are some reasons why it may be problematic as an explanation of what controls evolution. One issue is that mutations are random changes, and most random changes are harmful. Think of DNA as like programming code, and then ask yourself: what is the effect going to be of randomly changing something in a block of programming code? Any programmer will tell you: you'll probably mess things up. So how it is obvious that we should explain something such as the evolution of a highly specialized animal by evoking random mutations?
Another issue is that while blind chance evolution may be a pretty good way of explaining how we got from microbes to mammals, such a concept may be insufficient for explaining how we got microbes in the first place, and how we got from mammals to men. The latter, in particular, requires the appearance of all kinds of advanced human characteristics such as self-consciousness, spirituality, altruism, philosophical abilities, math abilities, and language abilities that may be very hard or impossible to explain by mere blind chance and mutations, for reasons discussed here.
Possibility 2: God
Of course, many believe that God is in control of evolution. One possible issue with this idea is that our universe seems to have many, many planets. Our sun is merely one star among billions in our galaxy, and there are billions of galaxies. There could easily be 1,000,000,000,000,000,000 planets on which life is evolving right now. If one imagines that the creator of the universe is directly involved in the evolution of life on each and every planet in our vast universe, that seems to be assigning a tremendous amount of work for any one being to do at one time. Perhaps too much work.
Possibility 3: Angels
Given the existence of as many as 1,000,000,000,000,000,000 or more planets on which life is evolving right now, it could be that a creator of our universe chose to divide up the job of controlling evolution on planets. Such a creator could have created subordinate spiritual beings to handle some of the work. The best word we have for such a concept is “angels,” although some might prefer some other term to avoid Christian connotations. It could be that some local spiritual beings are in control of our evolution, while the creator of the universe busies himself with other more pressing matters. Such angels might or might not look anything like traditional depictions of angels.
Possibility 4: Extraterrestrials
The idea that extraterrestrials from another planet have had a hand in earthly evolution is one that has been around for a long time. One flavor of it is the theory of panspermia. There are quite a few ancient astronaut enthusiasts who propose various theories of how Earth's history has been affected by alien intervention. One possible line of evidence in support of this theory are the many UFO sightings. Some UFO enthusiasts even have elaborate theories of how UFOs are abducting humans and gathering genetic samples from them, for the sake of creating a hybrid race of extraterrestrials and humans.
Other people attempt to explain the origin of earthly life by imagining extraterrestrial intervention billions of years ago, although that just pushes the problem farther away in time and space, leaving the problem of how life originated on the home planet of those extraterrestrials.
Possibility 5: Future earth inhabitants
This possibility is not quite as outrageous as it may seem. Researchers such as Daryl Bem of Cornell University have gathered evidence for precognition, an anomalous human ability to gain knowledge of the future. Some think that such evidence implies a doctrine of retrocausation, the idea that someone in the future can influence something that happened in the past (although there is debate about whether one implies the other). If the idea of retrocausation is valid, it could be that the current evolution of our planet is being controlled by people in the future, who may be taking care to make sure that our evolution is not incompatible with their eventual existence. In fact, Scientific American just published an article with some weird quantum goobledygook that may mean the door is open to such a possibility.
Possibility 6: Elevated afterlife spirits
Again I may say: this possibility is not quite as outrageous as it may seem. Near-death experiences and similar phenomena provide a possible evidential foundation for believing in an afterlife. Sometimes people who claim to be knowledgeable about the topic claim that in an afterlife there are various levels of existence or planes of existence, and that if you progress to a high enough spiritual level you are given the responsibility of controlling evolution on distant planets. But if elevated spiritual beings in an afterlife might control evolution on other planets, they might also control evolution on our own planet.
Of course, some would be depressed by the idea that our evolution might be controlled by our departed ancestors, but the idea is not more depressing than the idea that blind chance controls our evolution.
Possibility 7: Cosmic programming
On other posts on this web site (here and here) I have discussed the theory of a programmed material universe. The idea is that the universe has a kind of information infrastructure that drives cosmic evolution, propelling the universe on to ever higher heights of glory. Such an information infrastructure might include programming, a cosmic computation facility, and a cosmic database facility. Under such a theory, the universe has been programmed for success from the very beginning. Given no special attention, a particular planet might achieve astonishing feats of evolution, not by blind chance, but because the universe is programmed for such successes. Under such a theory the universe reaches levels of evolutionary success rather like a jet plane on autopilot might reach different destinations. It could be that evolution succeeds on planet after planet because the whole universe is in effect “on autopilot.” The next phase in human evolution may be something written in the details of the universe's software.
Does cosmic software control evolution?
Possibility 8: Puppet Masters in a Fourth Dimension
Imagine if there were beings in a world of only two dimensions: height and width. They would be like little photo cutouts moving around on a flat puzzle board. A person in a 3-dimensional world could move his hand down and change things in that 2D world, perhaps without any of those 2D beings noticing the intervention. Similarly, there could be beings in a fourth dimension who overlook our 3D world, intervening without us noticing. Such beings may be the puppet masters in control of evolution.
Possibility 9: Ourselves
Perhaps to find out who controls evolution, we need merely look in the mirror. It could be that biological evolution has been overshadowed by cultural evolution and technological evolution, which we ourselves control. So maybe we are the masters of our own fate.
Possibility 10: Cycles of evolution
Some historians such as Oswald Spengler have adopted cyclical theories of history. It could be that evolution works in cycles. Perhaps over and over again the same thing happens: life arises to ever greater heights, reaching a state of great intelligence, which leads to great power of destructiveness. Such technological power may lead to the destruction of the intelligent life form in a horrifying apocalypse. Then millions of years later life may again begin to move toward intelligence, only to destroy itself again after reaching great technological power. Such a cycle may have played out several times before, or this may be the first iteration in the cycle. We may be mere pawns in this sad cycle.
Possibility 11: Physical predestination
It could be that the end result of evolution is really determined by some blind deterministic factors which lock our planet into some destiny we cannot change. Evolution may be controlled by some inscrutable force of fate that we have no power to change. For further information please view Verdi's opera La Forza del Destino.
Possibility 12: Morphic gravitation
As the last possibility, I will mention an exotic possibility that is fascinating to consider. Let us imagine that for many biological species there is some external form or blueprint or schema that represents a more developed or evolved version of that species. Such a form or blueprint or schema may be called a morphic prototype, and it may exist as information rather than a material model. It could be that a species somehow tends to be very gradually “pulled” towards such a morphic prototype, through a slow process we can call morphic gravitation. We can imagine this process as being a tiny bit like one of those movie morphs, but instead of the morph occurring in a few seconds it might take place over many, many generations. So imagine a morphic prototype of the human species that is more evolved than our current species. Perhaps that morphic prototype depicts humans with larger brains. It might be that gradually our species is being pulled towards that prototype, which results in humans gradually gaining larger and larger brains. Such morphic prototypes might somehow have arisen naturally, or they might be part of some grand deliberate scheme for driving evolution.
I conclude that we simply don't know what force controls evolution. There are too many possibilities for us to have any certainty about the matter.