Many believers in auras attribute the to supernatural forces, “leaky Chakras” or “pure life force” emanating from living beings. Non-believers will sometimes ridicule these explanations and point to the complete absence of evidence for such “energy fields” or life forces.
I think these arguments are often dogmatic and actually unscientific. There may be no evidence of energy fields etc., but that does not mean that auras don’t exist, or that those who claim to see them are lying or deluded. It is dogmatic to deny a phenomenon just because we can’t explain it with current knowledge. We can’t make scientific progress with that attitude.
On the other hand the existence of a phenomenon without any current rational explanation is not evidence for the supernatural. These arguments are also detrimental to the advancement of knowledge because they rely on untestable explanations. Just imagine where we would be if we still thought that thunder and lightning was caused by the anger of gods!
Of course, things like auras can be investigated scientifically. Sandra and Mathew Blakeslee describe such investigations in their book The Body Has a Mind of Its Own: How Body Maps in Your Brain Help You Do (Almost) Everything Better.
They relate how a women who genuinely sees auras was investigated and found to have emotion-colour synesthesia. Synesthesia is a condition where awareness in one sense produces a response in another sense because of overlapping mind maps. Numbers have colours. Tastes have shapes. Sounds have a visual effect. This women reported colours associated with people and their names – presumably because of her emotional reaction to individuals.
So, it could be that some people really do see auras and these could be a natural construction of parts of their brain.
Now, we couldn’t make that advancement in understanding by taking up a dogmatic position. By claiming that auras don’t exist because they don’t fit in with current knowledge. Or by claiming that they do exist but have a supernatural or paranormal explanation.
By the way, The Body Has a Mind of Its Own is well worth reading. It’s a fascinating and fast moving area of science.