Dark matter and dark energy are supported by good observational evidence, dark matter since the 1930s. If something is observed, it is of no moment that theory doesn't explain it. It's there. Consciousness is there, because even if it can't be explained, it can be observed. So, if ESP could be observed, with anything like the certainty with which these other phenomena have been observed, then ESP would exist, theory or no theory.
But it hasn't been observed, with that, or indeed any, degree of certainty. Nor does any theory require it. In fact none explicitly permits it.
Life is known to exist, therefore we can propose, without doing violence to any current theory, that it exists independently in more than one place.
I argued that the ESP is by definition a sense that can't be explained. If it is explained, then by definition it is not ESP.
The Rhine Institute of the Paranormal once funded a study to determine whether pigeons used ESP to navigate. I heard about this during a tour of their North Carolina facilities. Although I haven't tried to document it, the story sounds very reasonable to me. True or not, it illustrates a fundamental problem in ESP studies.
Scientists already accepted the fact that pigeons could navigate, but no one had an explanation of how it was done. So since the Rhine Institute had 'established' ESP in humans, or rather the investigators thought so, it seemed reasonable to conjecture that ESP also helped the pigeons navigate.
The investigators found that pigeons were very sensitive to magnetic fields. They have an magnetic compass which is embedded in their neck. They navigate chiefly by means of this magnetic compass. This was very easy to validate once they came up with the hypothesis. Pigeons readily respond to all sorts of magnetic fields, including man made magnetic fields.
The conclusion of this study was that pigeons don't use ESP to navigate. They have a sense that is sometimes called magneto reception. They can determine the strength direction of ambient magnetic fields relative to their own body centered coordinates.
I want to point out that this is now well established by scientists. Pigeons do have magnetoreception. I am not sure how big the role of the Rhine Institute was in establishing this. However, I find it reasonable to suppose that the Rhine Institute really did contribute to establishing this fact.
I propose that the Rhine institute could have concluded differently. They could have concluded that pigeons do use ESP to navigate. They could have redefined ESP to include magneto reception as a special class. However, they hypothesized that magneto reception is not ESP.
Magnetoreception is not known in human beings. At least not yet. Maybe humans have it, but they don't respond in such a straightforward way to magnetic fields. Humans do respond to extremely large magnetic fields, not found on earth under natural conditions. However, this is not really magneto reception since the physical effects of such strong magnetic fields on electrolyte solutions is hard to ignore.
One could conjecture that humans use magneto reception with weaker magnetic fields to communicate on a subliminal level. Some unknown type of neural processing would be necessary to subtract out the huge background created by the earths magnetic field. However, maybe humans have such neural processing. Maybe in the future people will find some of these test for ESP in humans were biased by magnetoreception. In order to remain consistent, the Rhine Institute would still have to conclude that humans don't have ESP.
The implicit hypothesis of these studies is that ESP can't have a 'natural' explanation. So if everybody uses this hypothesis, then I suspect that the likelihood of ESP being 'proven' is rather low.
Saying that you have to find a mechanism for ESP in order for it to be proven makes the job impossible. ESP by definition is a sense without physical basis. If you then say it has to have a physical basis, the probability of finding it is truly zero.
Finding ETs looks like a cakewalk in comparison.