I would like to know the difference in meaning between 'useful' and 'helpful' when we talk about non-physical things such as advice, explanation, knowledge, etc.
When can you say that some advice/knowledge is useful? And when is it helpful?
When can you say that an explanation is useful? And when is it helpful?
How do you describe something useful but not helpful?
Because I know that sometimes something can be useful but not helpful.
Best Answer
A1. The differences between Helpful and useful is the willingness/usefulness or the act/effect;
The act/effect of somebody or something to help you achieve an objective is useful.
Whilst
Helpful, is the willingness of somebody or the usefulness of something to help you achieve an objective.
A2&3. You can use Helpful in regard to; somebody that willingly assists you or something that is an aid to your progress towards your objective.
You can use Useful in regard to somebody or something that is helpful, facilitates or is needed such that you can progress towards your objective
So whilst somebody who is helpful might be useful, something useful can always be helpful.
A4. An inanimate object, such as a tool can be useful but not helpful However, the use of that object could be Helpful.
The security guard was not helpful, he said that as I had no I.D. card I could not enter the building. I noticed that there was an internal phone on the wall next to the door and I asked if I could use it to ring the office. "Yes" he replied, that telephone is quite useful when you forget your I.D.