The Buddha criticized skeptics or ajñâninah who were those who believed not knowing is best if not the suspension of the effort to know. This implies that perhaps there is no one intelligent enough, or one who is an authority, that knows, fully, the truth of anything. Even if there were such a person, how might we know his statements are true since we all lack the necessary intelligence to determine if he is telling us the truth or not?
And so goes the world of the skeptic who were plentiful in the Buddha’s day. Unfortunately, modern Buddhism in the West has its fair share of skeptics. It is not that they reject Buddhism altogether but rather they reject important portions of Buddhism which they contend are unprovable such as rebirth and karma; and in some cases, even nirvana if it is transcendent. Overcoming their criticism is almost impossible. They are unwilling to be open minded if not innocent when studying the discourses of the Buddha.
Modern skepticism, we need to bear in mind, is not without its own set of dogmas, or let’s call them presuppositions for now. The arguments against rebirth involve deep attachment to the general claims of scientific materialism which have, to quite a degree, infected Western culture and thinking in which there can be nothing beyond physicality. When you are dead, that's it. This is not the skepticism of Pyrrhonism the outcome of which is supposed to be ataraxy, that is, calmness of mind.
Modern skepticism can and often does lead, inevitably, to despair which comes on the heels of its destructive criticism which seems almost irrational; which even in the face of plausible evidence seems even more determined to doubt. An example of this is NDEs (Near Death Experiences). I haven’t found many Western Buddhists excited about this. They are not going to be won over by testimony of those who have experienced an NDE. Anything paranormal such as Dr. Stevenson's 1987 book, Children Who Remember Previous Lives: A Question of Reincarnation seems out of place in the hall of modern Western Buddhism including Zen Buddhism. Modern Buddhism, in my opinion, has too many skeptics.