It is difficult to figure out when humans are just telling tall tales or accurately reflecting real experiences.
However, it is an intellectual error to dismiss all anecdotes as false.
That is one of the flaws of science. Science uses averages to reach conclusions, which means it has to dismiss outlying data.
That outlying data is tough to assimilate—but some small part of it will be the basis of future revolutions in human intellectual progress.
I am convinced that Terence McKenna, Rupert Sheldrake, Carl Jung, Jacque Vallee and John Mack are true intellectual giants—but are way ahead of their time.
They will be understood and appreciated by future generations.
Nnnnnot really. Science uses the scientific method (surmise a theory, collect data, try to disprove the theory. If not dis-proven, then maybe its true).
Statistical science, a branch of science, will throw out outlying data when its presumed the outliers are there because of things like measurement noise or even faulty measurements. Such data should not be discarded unless one can justify a good reason to do so. Discarding without reason can mask failings in the theory, and slow the process of finding the truth.
Another part of the scientific process is repeatability. An experiment must be repeatable or you have left something important out of any theory.
So you may choose not to dismiss someones tale, but you need much more than a tale (likely of someones experience while under the influence) to call that a point of evidence in some scientific experiment.
I am convinced that Terence McKenna, Rupert Sheldrake, Carl Jung, Jacque Vallee and John Mack are true intellectual giants
No offense again, but those names mean nothing to me, so I am not convinced. Copernicus, Newton, Galileo, Einstein, Von Braun, Bell (Alexander Graham, not Art), Hubble, those are examples of intellectual giants, men upon who shoulders many others stood on to accomplish great feats in human history. Steven Hawkings, not so much.