In my opinion, one has to distinguish between seeing an answer as

• an answer to the question,

and

• a solution to the problem.

When I'm reading a question that I know the answer to (i.e., I can provide the solution to the problem) I write an answer.

However, when I'm reading a question for that I might have seen/found a/the problem/flaw (i.e., I neither know that for sure nor did I test my idea/feeling) I post a comment.

I don't intend to do whatever I want, as @Chip described it—this is just my personal intuitive way of responding to the question under the given circumstances.

Oftentimes, however, the actual solution is either just a one-line (or even one-word) answer, and when posting this as a comment, one does not yet know this is the answer.

Also, suppose an existing answer does lack only a tiny bit to be complete (i.e., the problem is not yet solved). In that case, I would choose to comment this answer instead of copying the whole code, then add/edit the single missing/wrong line, and provide this (complete) answer. No matter if the particular (incomplete) answer was written just a couple minutes ago or a decade ago, I don't feel right about posting an answer in that case.

Concluding, I don't see a problem with writing a maybe-answer as a comment, and then turn it into an actual answer if it is the answer to the question. But that's just my gut feeling.

// EDIT @Chip You're talking about building up a knowledge base, and I consider writing answers and comments as I explained before doing exactly this. Otherwise you'd build up an assumption base rather than a knowledge base.

I absolutely agree in that comments that turn out to be answers should be added as answers to the question, and thus help building up the Q&A knowledge base.
Posting everything that in any way might have to do with the question as an answer is, in my opinion, neither reasonable nor does it serve the site's aim.
Prohibiting comments (which have less value/impact, as @s_ha_dum stated) consistsing of experiments, assumptions and guesses, on the other hand, and thus forcing users to either write an answer (and live with being down voted) might lead to even more unanswered questions.

As for the specific circumstances... I didn't mean the specific circumstances of the user who asked the question. Of course, posting a valid answer, which might not completely solve the original question under its specific circumstances, but in general, should be posted as an answer.
But that's not what I meant (and wrote). It's more these maybe answers that I'm talking about (and, as far as I understood, @s_ha_dum, too). If I'm not sure whether I'm about to post an answer at all (i.e., either solving the specific problem stated in the question, or solving the problem in general) I just provide my thoughts on that as a comment.

In my opinion, one has to distinguish between seeing an answer as

• an answer to the question,

and

• a solution to the problem.

When I'm reading a question that I know the answer to (i.e., I can provide the solution to the problem) I write an answer.

However, when I'm reading a question for that I might have seen/found a/the problem/flaw (i.e., I neither know that for sure nor did I test my idea/feeling) I post a comment.

I don't intend to do whatever I want, as @Chip described it—this is just my personal intuitive way of responding to the question under the given circumstances.

Oftentimes, however, the actual solution is either just a one-line (or even one-word) answer, and when posting this as a comment, one does not yet know this is the answer.

Also, suppose an existing answer does lack only a tiny bit to be complete (i.e., the problem is not yet solved). In that case, I would choose to comment this answer instead of copying the whole code, then add/edit the single missing/wrong line, and provide this (complete) answer. No matter if the particular (incomplete) answer was written just a couple minutes ago or a decade ago, I don't feel right about posting an answer in that case.

Concluding, I don't see a problem with writing a maybe-answer as a comment, and then turn it into an actual answer if it is the answer to the question. But that's just my gut feeling.

// EDIT @Chip You're talking about building up a knowledge base, and I consider writing answers and comments as I explained before doing exactly this. Otherwise you'd build up an assumption base rather than a knowledge base.

I absolutely agree in that comments that turn out to be answers should be added as answers to the question, and thus help building up the Q&A knowledge base.
Posting everything that in any way might have to do with the question as an answer is, in my opinion, neither reasonable nor does it serve the site's aim.
Prohibiting comments (which have less value/impact, as @s_ha_dum stated) consistsing of experiments, assumptions and guesses, on the other hand, and thus forcing users to either write an answer (and live with being down voted) or do not respond at all, might lead to even more unanswered questions.

As for the specific circumstances... I didn't mean the specific circumstances of the user who asked the question. Of course, posting a valid answer, which might not completely solve the original question under its specific circumstances, but in general, should be posted as an answer.
But that's not what I meant (and wrote). It's more these maybe answers that I'm talking about (and, as far as I understood, @s_ha_dum, too). If I'm not sure whether I'm about to post an answer at all (i.e., either solving the specific problem stated in the question, or solving the problem in general) I just provide my thoughts on that as a comment.

In my opinion, one has to distinguish between seeing an answer as

• an answer to the question,

and

• a solution to the problem.

When I'm reading a question that I know the answer to (i.e., I can provide the solution to the problem) I write an answer.

However, when I'm reading a question for that I might have seen/found a/the problem/flaw (i.e., I neither know that for sure nor did I test my idea/feeling) I post a comment.

I don't intend to do whatever I want, as @Chip described it—this is just my personal intuitive way of responding to the question under the given circumstances.

Oftentimes, however, the actual solution is either just a one-line (or even one-word) answer, and when posting this as a comment, one does not yet know this is the answer.

Also, suppose an existing answer does lack only a tiny bit to be complete (i.e., the problem is not yet solved). In that case, I would choose to comment this answer instead of copying the whole code, then add/edit the single missing/wrong line, and provide this (complete) answer. No matter if the particular (incomplete) answer was written just a couple minutes ago or a decade ago, I don't feel right about posting an answer in that case.

Concluding, I don't see a problem with writing a maybe-answer as a comment, and then turn it into an actual answer if it is the answer to the question. But that's just my gut feeling.

In my opinion, one has to distinguish between seeing an answer as

• an answer to the question,

and

• a solution to the problem.

When I'm reading a question that I know the answer to (i.e., I can provide the solution to the problem) I write an answer.

However, when I'm reading a question for that I might have seen/found a/the problem/flaw (i.e., I neither know that for sure nor did I test my idea/feeling) I post a comment.

I don't intend to do whatever I want, as @Chip described it—this is just my personal intuitive way of responding to the question under the given circumstances.

Oftentimes, however, the actual solution is either just a one-line (or even one-word) answer, and when posting this as a comment, one does not yet know this is the answer.

Also, suppose an existing answer does lack only a tiny bit to be complete (i.e., the problem is not yet solved). In that case, I would choose to comment this answer instead of copying the whole code, then add/edit the single missing/wrong line, and provide this (complete) answer. No matter if the particular (incomplete) answer was written just a couple minutes ago or a decade ago, I don't feel right about posting an answer in that case.

Concluding, I don't see a problem with writing a maybe-answer as a comment, and then turn it into an actual answer if it is the answer to the question. But that's just my gut feeling.

// EDIT @Chip You're talking about building up a knowledge base, and I consider writing answers and comments as I explained before doing exactly this. Otherwise you'd build up an assumption base rather than a knowledge base.

I absolutely agree in that comments that turn out to be answers should be added as answers to the question, and thus help building up the Q&A knowledge base.
Posting everything that in any way might have to do with the question as an answer is, in my opinion, neither reasonable nor does it serve the site's aim.
Prohibiting comments (which have less value/impact, as @s_ha_dum stated) consistsing of experiments, assumptions and guesses, on the other hand, and thus forcing users to either write an answer (and live with being down voted) might lead to even more unanswered questions.

As for the specific circumstances... I didn't mean the specific circumstances of the user who asked the question. Of course, posting a valid answer, which might not completely solve the original question under its specific circumstances, but in general, should be posted as an answer.
But that's not what I meant (and wrote). It's more these maybe answers that I'm talking about (and, as far as I understood, @s_ha_dum, too). If I'm not sure whether I'm about to post an answer at all (i.e., either solving the specific problem stated in the question, or solving the problem in general) I just provide my thoughts on that as a comment.