In my last post regarding the relationship between faith and confirmation bias, I was responding to a common idea in contemporary skeptic circles that faith is a matter of accepting a proposition (or a set of propositions) without any evidence. One of my readers pointed out that this definition of faith didn't make much sense, and I agreed that it doesn't make much sense, though for somewhat different reasons related to the evidence of human belief formation.
It's important to note that not every contemporary skeptic agrees with this definition; some have proposed that faith is a matter of accepting a proposition (or a set of propositions) based on insufficient evidence rather than doing so without any evidence. This is certainly a better way of expressing it, for reasons we will see shortly.
Most people who believe claims that we generally think of as faith claims are doing so based on some sort of evidence. Even if that evidence is just the word of their parents or friends, or the evidence is their own intuitions about the significance of a powerful experience they had, it's still a kind of evidence. I suspect that most of those who view faith as being without evidence do so because their standard of evidence only admits the kind of evidence we get from a laboratory and excludes a priori the evidence we get from our life experiences or from the wisdom of others.
The reason that is sometimes given for this is that the aforementioned forms of evidence are exclusively subjective rather than objective. And sometimes contemporary atheists characterize this belief in the conclusions one has drawn from subjective experiences rather than objective evidence as being a delusion. This way of understanding faith has some interesting implications.
For example, on this view of the use of exclusively subjective evidence to come to conclusions about what is objectively true, most transgender individuals are by definition engaging in a delusion when they conclude based on their subjective experience that, though they were born in a male body, they are actually a woman. Some atheists might be totally fine with the implication that transgender individuals are engaging in a self-delusion akin to religious faith, but many contemporary atheists would not be fine with that implication.
Even for those who would be willing to accept that implication, the society we live in seems to offer yet another difficulty to them in the form of the mental health profession, which apparently does count subjective experiences as evidence on a regular basis. Even when those subjective experiences lead to the conclusion that a person is laboring under a delusion, we admit them as evidence of an objective truth, as we can see from considering a generic case of mental illness.
Let's suppose, for example, that we have someone who suffers from paranoid schizophrenia. This person hears voices that seem very real to him advising him that his family is trying to poison him. He hears voices that seem very real to him advising him that he should kill them. When he relates these subjective experiences to a psychiatrist or a psychologist, they are part of the evidence the psychiatrist or psychologist uses to diagnose him. Even though the patient may be wrong about the existence of the voices anywhere other than outside his head, his subjective experiences are at the very least important empirical evidence for us to consider when diagnosing his condition and evaluating his treatment.
This is a fairly clear case of basing claims about objective truth on subjective experiences, both because the schizophrenic patient and the psychiatrist or psychologist are basing their beliefs about the the objective reality of the situation on their subjective experiences of the patient. The difference here is that a psychiatrist or psychologist would infer from the patient's subject experiences not that the voices were somehow objectively real, but rather that the patient's subjective experiences were only evidence of a subjective experience and they needed treatment for the diagnosed condition that is objectively the cause of their symptoms.
Most people don't disagree in practice on the question of whether subjective experiences count as empirical evidence or not. Where they actually disagree is on the question of what we can rationally infer from that evidence. The patient with the delusion may believe that he can rationally infer from the evidence of his subjective experiences that real people are telling him to do terrible things. The psychiatrist believes that we can rationally infer from the evidence of the patient's subjective experiences that the patient is suffering from paranoid schizophrenia.
None of this is meant to suggest that it's obvious that we should accept one instance of subjective evidence via a person's testimony as proof of the occurrence of an event or the existence of some novel creature. While we do use eyewitnesses in our courts and we use the accounts of explorers and scientists in demonstrating the existence of new lands or new species, we check those eyewitness accounts to make sure they fit with other evidence and we prefer corroborating testimony about new lands and new species.
Nonetheless, it is clear that our beliefs are not formed without reference to the evidence of subjective experience, and I'm not sure why we would regard the subjective experience of someone who claims that they were abducted by aliens any differently than the experience of someone who claims they saw a mammal with webbed feet that lays eggs (duck-billed platypus). We should subject both cases to the test of corroborating evidence. If we can go see the aliens or the duck-billed platypus for ourselves, we ought to believe it. And even if we can't, we should at least entertain the possibility that they exists and we simply weren't able to see it for some reason.
That's a consistent standard of evidence, though some would a priori rule out the possibility of extra-terrestrial life and therefore reject its existence out of hand based on their own consistent standard of evidence. They have faith that only those propositions which can be formulated mathematically and verified by scientific standards of evidence are true propositions.
There's no particularly good evidence that their belief is true, but we all have faith in something in the sense that we all operate under working unproven assumptions, and I respect their consistent position. Ultimately the relationship between faith and evidence is that we have no other choice but to have faith in a standard of evidence and hope that our confirmation bias isn't leading us to interpret our reality as validating our faith completely despite the evidence that runs counter to it.