With regards to your example, you try to fix the gap between “consumption will increase” and “that will be a bad thing as a whole” by claiming little good use and much bad use. But I don’t think that’s the strongest way to bridge that gap.
Rather, I’d suggest that the good use has negligible positive utility—just another way to relax on a Friday night, when there are already plenty of ways to relax on a Friday night, so how much utility does adding another one really give you? - while bad use has significant negative utility (here I may take the chance to sketch the verbal image of a bright young doctor dropping out of university due to bad use). Then I can claim that even if good-use increases by a few orders of magnitude more than bad-use, the net result is nonetheless negative, because bad use is just that terrible; that the negative effects of a single bad-user outweigh the positive effects of a thousand good-users.
As to your main point—what to do when your best effort to fill the gap is thin and unconvincing—the simplest solution would appear to be to go back to the person proposing the position that you are critically commenting about (or someone else who shares his views on the subject), and simply asking. Or to go and look through his writings, and see whether or not he addresses precisely that point. Or to go to a friend (preferably also an intelligent debator) and asking for his best effort to fill the gap, in the hope that it will be a better effort.
Entirely within the example, not pertaining to rationality per se, and I’m not sure you even hold the position you were arguing about:
1) good use is not restricted to relaxing on a Friday. It also includes effective pain relief with minimal and sometimes helpful side-effects. Medical marijuana use may be used as a cover for recreational use but it is also very real in itself.
2) a young doctor dropping out of university is comparable and perhaps lesser disutility to getting sent to prison. You’d have to get a lot of doctors dropping out to make legalization worse than the way things stand now.
My actual position on the medical marijuana issue is best summarised as “I don’t know enough to have developed a firm opinion either way”. This also means that I don’t really know enough to properly debate on the issue, unfortunately.
Though, looking it up, I see there’s a bill currently going through parliament in my part of the world that—if it passes—would legalise it for medicinal use.
what to do when your best effort to fill the gap is thin and unconvincing—the simplest solution would appear to be to go back to the person proposing the position that you are critically commenting about (or someone else who shares his views on the subject), and simply asking.
So, you go back to the person you’re going to argue against, before you start the argument, and ask them about the big gap in their original position? That seems like it could carry the risk of kicking off the argument a little early.
“Pardon me, sir, but I don’t quite understand how you went from Step A to Step C. Do you think you could possibly explain it in a little more detail?”
Accompanied, of course, by a very polite “Thank you” if they make the attempt to do so. Unless someone is going to vehemently lash out at any attempt to politely discuss his position, he’s likely to either at least make an attempt (whether by providing a new explanation or directing you to the location of a pre-written one), or to plead lack of time (in which case you’re no worse off than before).
Most of the time, he’ll have some sort of explanation, that he considered inappropriate to include in the original statement (either because it is “obvious”, or because the explanation is rather long and distracting and is beyond the scope of the original essay). Mind you, his explanation might be even more thin and unconvincing than the best you could come up with...
With regards to your example, you try to fix the gap between “consumption will increase” and “that will be a bad thing as a whole” by claiming little good use and much bad use. But I don’t think that’s the strongest way to bridge that gap.
Rather, I’d suggest that the good use has negligible positive utility—just another way to relax on a Friday night, when there are already plenty of ways to relax on a Friday night, so how much utility does adding another one really give you? - while bad use has significant negative utility (here I may take the chance to sketch the verbal image of a bright young doctor dropping out of university due to bad use). Then I can claim that even if good-use increases by a few orders of magnitude more than bad-use, the net result is nonetheless negative, because bad use is just that terrible; that the negative effects of a single bad-user outweigh the positive effects of a thousand good-users.
As to your main point—what to do when your best effort to fill the gap is thin and unconvincing—the simplest solution would appear to be to go back to the person proposing the position that you are critically commenting about (or someone else who shares his views on the subject), and simply asking. Or to go and look through his writings, and see whether or not he addresses precisely that point. Or to go to a friend (preferably also an intelligent debator) and asking for his best effort to fill the gap, in the hope that it will be a better effort.
Entirely within the example, not pertaining to rationality per se, and I’m not sure you even hold the position you were arguing about:
1) good use is not restricted to relaxing on a Friday. It also includes effective pain relief with minimal and sometimes helpful side-effects. Medical marijuana use may be used as a cover for recreational use but it is also very real in itself.
2) a young doctor dropping out of university is comparable and perhaps lesser disutility to getting sent to prison. You’d have to get a lot of doctors dropping out to make legalization worse than the way things stand now.
My actual position on the medical marijuana issue is best summarised as “I don’t know enough to have developed a firm opinion either way”. This also means that I don’t really know enough to properly debate on the issue, unfortunately.
Though, looking it up, I see there’s a bill currently going through parliament in my part of the world that—if it passes—would legalise it for medicinal use.
Have you read “Marijuana: Much More Than You Wanted To Know” on Slate Star Codex?
No, I have not.
So, you go back to the person you’re going to argue against, before you start the argument, and ask them about the big gap in their original position? That seems like it could carry the risk of kicking off the argument a little early.
“Pardon me, sir, but I don’t quite understand how you went from Step A to Step C. Do you think you could possibly explain it in a little more detail?”
Accompanied, of course, by a very polite “Thank you” if they make the attempt to do so. Unless someone is going to vehemently lash out at any attempt to politely discuss his position, he’s likely to either at least make an attempt (whether by providing a new explanation or directing you to the location of a pre-written one), or to plead lack of time (in which case you’re no worse off than before).
Most of the time, he’ll have some sort of explanation, that he considered inappropriate to include in the original statement (either because it is “obvious”, or because the explanation is rather long and distracting and is beyond the scope of the original essay). Mind you, his explanation might be even more thin and unconvincing than the best you could come up with...
I think the idea was, ‘when you’ve gotten to this point, that’s when your pre-discussion period is over, and it is time to begin asking questions’.
And yes, it is often a good idea to ask questions before taking a position!