The paranormal arena currently contains a wide range of topics for investigation,
1. Astral Travel (as discussed on another thread); possibly a self guided dream state with a specific entry and exit procedure (hypnagogic images, vibration, entry)
2. Near Death Experiences (NDE); often reported by people passing through a transitory "near death" state during medical operations.
3. Out of Body Experience (OBE) - witnessing external events from a remote position
4. Remote Viewing - structured multiple viewer methodology to assess future and distant outcomes (used apparently by USA and USSR for possible military advantage)
5. Electronic Voice Phenomena (EVP) - ghost voice acquisition on analog or digital tape recorders
6. Shadow People - ephemeral, fleeting images that are caught out of the corner of the eye
7. Abductions - self explanatory
8. Implants - as above
9. - "UFOs" - as above
10. Aliens - apparently many types e.g. "greys" etc
I am sure there are many more.
Science, perhaps, has two main phases; phase 1 is conjectural and requires imagination and foresight prior to formulating a more solid framework. This phase has many false paths and is experimental. The second phase is one of refinement. In this phase, theories can be proposed and tested, used to corroborate ideas or to reject ideas.
Quantum mechanics, for example, didn't get invented overnight; it must have taken a lot of preliminary conjecture before it could be formulated as communicable ideas.
Even in science though, people are not always rational. From memory, Pythagoras had a student Hisspassis (excuse my spelling) who proved that the square root of two could not be rational i.e. not p/q where p and q are integers with no common factors. This infuriated Pythagoras - surely numbers must be "perfect". Pythagoras needed a solution and thought long and hard on the problem at hand. Then he had an idea. One day Hissapassis was sailing on the ocean. Pythagoras had Hisspassis thrown overboard. Hisspassis drowned. The problem was solved.
The difficulty with paranormal research is that it remains in phase 1 and is difficult to replicate. This is not necessarily a permanent situation. Further, some phenomenon may be associated with intelligent agents that do not wish for their presence to be discerned. This could be a "cop out" as science has no obligation to prove theories; it just follows a useful methodology that has secure progress. It is not strong on imagination per se, but it is strong on process.
There may be many things that exist that evade immediate observation. "Dark matter" is one such example; presumably proposed as an alternative to Einstein's "cosmological constant" - a fiddle factor introduced to "stabilize" the evolution of the universe (predictive theory). However we can only infer its existence but not infer "dark matter" as representing a sole explanation. Is "Dark Matter" therefore in the same category as many paranormal phenomena?
It seems sensible to me at least that theories should progress from a conjectural phase to one of refinement and testability. I have heard that Princeton University has a number of EGGs (I forget the acronym) scattered around the world generating random numbers. These are communicated back to a central site and analyzed for probability anomalies, like unexpected correlations. It has been claimed that correlation "spikes" occur when certain major earth events occur, e.g. prior to large earthquakes, the twin towers incident etc.
So science sometimes takes "paranormal" concepts seriously - at least for the purpose of experiment. Again, from Einstein wrt particle entanglement, "spooky action at a distance" is one of his quotes I read on the subject :wink: [/i]