No, we cannot know if a proposition is true without supporting evidence. Until such time as evidence is provided, the default position is one of non-existance. You cannot provide evidence for the non-existance of an object.
This is a criteria that was not in your definition (that the default position must be non-existence for propositions involving the existence of something). I have no problem with that, but I'm just pointing out that your definition was inadequate to address this case.
The problem is that you also cannot provide evidence for the non-existence of intelligent aliens, so by that criteria, the default position ought to be one of non-existence.
Here we hit upon a problem - what is your definition of 'conclusive' evidence? How much evidence is required, and of what type, before it is considered 'conclusive'? I would say that there the evidence for evolution is conclusive. I would say the same about the germ theory of disease.
Exactly my point -- there is no definition of "conclusive" that can determine how much evidence is required and of what type. I tend to agree that the evidence for evolution and the germ theory of disease are indeed so overwhelming that they would qualify as "conclusive," but there is no objective, clear line between what is conclusive and what is not conclusive. Which is precisely why I don't think you can come up with a definition for "skepticism" that will allow us to objectively determine whether a given proposition is skeptical or not.
But you also hit upon another point - you say that the method is inconclusive. That is false. The method is complete - the answer we arrive at in the face of missing or incorrectly interpreted evidence is inconclusive, tentative at best.
I could only have meant that the
results of the method aren't necessarily conclusive -- that you cannot necessarily use the method to determine whether a given proposition is skeptical or not.
Why do you consider that a bad thing? I would argue that an inconclusive answer is a good thing for this method to provide, as it tells us that something about our evidence is not right - it has been incorrectly interpreted or there is some missing.
I don't consider that a bad thing. What gave you the impression that I did?
Skepticism does not deal in absolutes, it forces us to examine our beliefs and tells us what beliefs we should, at least tentatively or temporarily, lend our support to and accept as fact. The unchangable and the certain are the domain of faith, along with an inaccurate and often dangerous view of the world. I will take the uncertain accuracy of skepticism over the blind inaccuracy of faith any day.
I disagree. Skepticism tells us that we should never accept anything as fact unless it actually
is fact. And only in cases where the evidence clearly points to a particular conclusion can skepticism necessarily tell us which conclusion to lend our support to.
If my answer were, "Yes, P and ~P are both skeptical," I would have said that instead of what I did say. You are oversimplifying the matter, and it bores and annoys me - don't tell me what I should say and don't tell me what I meant to say. I choose my words carefully, and I choose my words for a reason. If you disagree with my words you are welcome to make your case - you are not welcome to change my words so that they seem to support your oversimplified strawman notion of skepticism.
Here is what you
did say in response to my query about whether both P and ~P can be skeptical according to your definition given that there is valid evidence for each:
If it is possible to reach different conclusions based on the same evidence, then all conclusions reached via skepticism are reasonable positions to hold, with the obvious concession that as different positions can be reached given the same evidence, there is either a flaw somewhere in our understanding of the evidence, or there is missing evidence.
For that, you'll have to talk to someone who works in the evolutionary sciences. I, personally, have very little knowledge of exactly what the world was like in the past - there are, however, many scientists who do have reasonable hypotheses as to how life may have developed, and what the conditions were like. Not only that, but we know of many conditions under which life thrives merely by looking at the world around us and noting the multitude of environments capable of supporting life.
It is true that we know of many varied conditions under which life can
survive, but we have very little knowledge of the conditions under which life
developed. Nor do we know how close conditions must be to those conditions under which life on this planet developed. And, yes, there are scientists who have
reasonable hypotheses as to how life
may have developed, and what the conditions were like, but that's not quite the same thing as "we are aware of the conditions under which at least one form of intelligent life can arrive - us."
We won't have any evidence of that life until we actually send something off to check, but that doesn't make the hypothesis automatically unreasonable or unskeptical.
According to your definition, only propositions with valid evidence would be considered skeptical, so this one wouldn't qualify. So you seem to be modifying the definition again, which again I have no problem with. But by what criteria can we determine whether a hypothesis is skeptical or unskeptical when there is a lack of evidence?
Except we have additional relevant information regarding the possibility of extraterrestrial life that we do not have regarding god. That is the reason that one can apply skepticism to claims about the existence of extraterrestrial life and decide that it is probable, or highly likely.
Sure, one can decide that it is probable, or highly likely, or one can just as easily decide that it is
improbable, or highly
unlikely. We simply don't know the conditions under which intelligent life on this planet developed, nor do we know how close conditions must be to those unknown conditions for intelligent life to develop, nor can we determine the probability of those unknown conditions under which intelligent life can develop occurring elsewhere. Some scientists believe that a certain event (or series of events) occurred that were very specific to our planet which caused the development of intelligent life, and therefore those scientists assign a very low probability to the existence of intelligent life outside of our solar system. Other scientists believe that the conditions are not specific to our planet, and therefore assign it a higher probability. In other words, the so-called "information" (that we exist) only helps us determine that the existence of intelligent aliens is
possible (i.e. that the probability is greater than 0% and less than 100%). In what way do you consider that "relevant information?"
If you disagree with that, kindly tell me which statement of the following you disagree with:
- There is evidence for the existence of life; or
- There is no evidence for the existence of god.
I don't disagree with either (although some might disagree with the second). Of course, I wasn't comparing the existence of life with the existence of a god. I was comparing the existence of intelligent alien life with the existence of a god, a difference which would change the first statement dramatically.
What criteria are you using to determine that one can have either opinion about the existence of aliens (of which there is no conclusive evidence for either position), but cannot have either opinion about the existence of a god (of which there is no conclusive evidence for either position)?
I don't need to modify my definition - your 'problems' with my definition are only problems in your own mind. Skepticism does not deal with certainty - if you want the warm fuzzy feeling of certain knowledge, join a doomsday cult like Heaven's Gate or the Catholic Church, and leave those of us who value accuracy over certainty alone.
Again, I'm not sure what makes you think that I want "the warm fuzzy feeling of certain knowledge" since I'm the one claiming that we lack certain knowledge about whether a given proposition can necessarily be objectively determined to be skeptical or not.
I'm fine with the definition you posted, as long as you realize that it either cannot be used to make such a determination in cases where there is no conclusive evidence, or else either allows certain beliefs that you probably believe to be unskeptical or disallows certain beliefs that you probably believe to be skeptical.
-Bri