What role does the 'voice of reason' play in the group?
It is a saying used in contrast to an emotional approach:
- the ability of a healthy mind to think and make judgments, especially based on practical facts. (Cambridge Dictionary)
If you are thinking about making risky investments, "the voice of reason" will suggest not to do that and be very careful.
Ngram: the voice of reason
The voice of reason is the person who tries to get the group to adopt decisions using evidence and logic. [...] – deadrat Dec 17 '15 at 9:33
I disagree. I believe the voice of reason is just giving advice to support both sides so that the person can make a good sound decision based on facts, rather than emotional thinking. I have been told I am the voice of reason, I reserve judgement and support all my friends and families dreams 💯 percent. However, if there is another angle to this decision, I present what I know about the subject giving others another view. Never would I steal anyone's hopes and/or dreams, ever.