Original thinkers ought to have the courage to pursue ideas on their own - even when those around them are negative. But that's not to deny that there are some situations where groups can be helpful in coming up with good ideas.
Someone in a group might have some information that could help develop an idea or even indicate why the idea is likely to work. This special knowledge might not have been available to the person who had the original idea.
Someone in the group could have the technical knowledge to suggest how the idea might be carried out. The originator of the idea might be stuck at the concept level. So a practical method of delivering the concept is important.
Several people in the group might have suggestions for modifications or improvements on the idea. Such suggestions could overcome difficulties, dangers or obstacles. Such suggestions could enhance the power or practicality of the idea.
People who are not particularly good at generating ideas themselves might still be good at improving the ideas of others. A different sort of thinking is needed.
Someone in the group could know of a similar idea that had indeed been tried. That person could then tell what had occurred. Somebody in the group might have some special technical knowledge which could either help the idea or inhibit it.
Also consider the stimulus value of a group. Somebody else's idea, or even a remark, could stimulate a new idea or a new line of thinking.
There is a further special value in a group. If everybody likes and is enthusiastic about the idea, that is of huge benefit to the originator of the idea and gives that person confidence and energy to pursue the idea further. Somebody in the group might even offer to help in this regard.
Even if it is not necessary for the generation of ideas, a group can still be of use towards their development. This development can take the form of suggestions regarding how the idea generated could be delivered in a practical way.
The development might also take the form of fundamental improvements in the idea and the value the idea could deliver.
As regards the judgment of ideas, a group can be very helpful - provided it has the correct attitude. It is very difficult for the idea's originator to judge whether their idea is feasible and whether it will really deliver the suggested value.
The opinion of others has value. It is true that the supportive judgment of one other person with knowledge of the field might be sufficient. Because a group contains different opinions, knowledge and experience, this contribution might be even better than one from an individual.
But it is important that the judging group has a positive attitude.
A group made up of people who are inclined to be negative, jealous or ego-driven can kill even the best ideas. In such cases, the chairperson of the group should insist that each member of the group make an effort to spell out the positive aspects of the idea.
A group that is made up of people who work in the area of the new idea can be very helpful in suggesting practical methods in which the idea can best be implemented.
Implementation might not be as exciting as creativity, but it is always of equal importance. Valuable ideas are those that are usable and used.