Logic without experience/experimentation can not achieve certainty

Should be fun! -----------A few notes on The Fool's clarification remarks:By semantics and common sense I do indeed mean "using semantics to weasel a win from a debate" and in general supporting arguments that we all know to be false just because we are opponents. The same goes for common sense. I mean common sense in a common sense way :PSorry if there are meanings behind these two concepts that I am missing. I am open to directions on where to look for clarifications if that becomes a problem. I think though that the meanings are going to become clear when I proceed with my points. Finally, although I am not going to totally subscribe to the Principle of Charity as I did not have the time to investigate its meaning in full, I like the idea. I think Con's is using it to set the tone of the debate in a more conversational manner (in contrast to pure competition). Note: I am living in the UK but I am actually Greek. Not that this is part of my argument :P-----------Ok. . let's move to my points. In this debate I put forward the proposition that philosophical discourse using ideas for which we have no certainty can not be fruitful. Logic is of course valid as a means of manipulating symbols and producing logical results. The problem we are facing is that we use valid logical structures but the concepts behind our premises sometime range from vague to completely unknown. This is more apparent in discussions about big issues such as the meaning of life, god, purpose of the universe etc. It can also be vague when dealing with human things like debates on morality or politics but in these subjects it is definitely more routed in common sense. To clarify what I mean observe the following examples:1. A->BB->CTherefore, A->C.2. Sissi is a catAll cats have a tailtherefore Sissi has a tailUntil here everything is good. We are all certain that all cats have a tail (from our experience), therefore we are certain of the result of the argument. But what if the argument was like that:3. Sissi is a catAll cats possess 38 chromosomestherefore Sissi possesses 38 chromosomesHmm. . Sounds plausible since it appears scientific, but we need to check if it is true. In order to know that it is true we would have to actually be a biologist or at least understand what a chromosome is and the mechanism by which we can find out that a cat has 38 chromosomes. Ideally we should also apply the procedure, make the count and finally know that the statement is true. Of course most people will go up to checking Wikipedia (as I just did myself) and maybe a couple more sources if they want to 'make sure'. So quite different types of 'certainty' there, and I am sure everyone will agree that his/her confidence on the 2nd argument is a lot higher than the 3d one (except if you are indeed a biologist). In any case we can definitely say that it is at least plausible to attain that knowledge and not completely futile to argue the point without doing all the research as our experience has shown that science is trustworthy. Now the real problem comes when the discussion goes into subjects that are dealing with unseen and unmeasurable concepts. Take this as an example:4. Sissi is a biological organismAll biological organisms have a soulTherefore Sissi has a soulProbably at this point you are all thinking here is another atheist preparing the ground for his attack :) Well that is not the case but it is not todays topic either. I am sure it is immediately apparent where I am getting at. What is a soul? How do we know that cats have one? Now, if you can define soul and prove, or at least indicate its existence through the scientific method or direct experience, then we can continue with our discussion. If not, a soul (whatever that is) may or may not exist and one thing is certain: we can not move any more closer to certainty in this logical argument. Conclusion----------I have indicated why certainty can come from experience or experimentation. There is the potential that it can be reached using logic if the individual elements are already certain. If that is not the case logical argumentation is futile and should stop (except if it is used as a form of entertainment). Can Con provide a logical example where this is not the case?