Are your thought patterns valid? Are your premises true? Is your mind sound?
Buddhism further asks are your mental states wholesome? Are they conducive to enlightenment, wisdom, freedom from delusion?
There are many things we can do while alone to clean up our thought processes. And there are some things we can only do with the help of another person.
Only another person can tell us if our premises, thoughts, and conclusions (however tentative) about them are true, valid, and sound.
Buddhism has a concept of a “spiritual friend,” a “good friend,” a noble friend,” or an “admirable friend.” All of these terms are translations of the Pali Kalyāṇa-mittatā, which is well-explained at that link. (Chinese 善知識). That link is well-worth reading in full.
From the link above and from many years of working with Buddhist literature and people, my sense is that a Buddhist “good friend” is someone who is to be admired and emulated. They are similar to what we mean today by mentors or “good role models.”
I deeply respect the concept of a Buddhist good friend, but find it lacks what I consider the preeminent virtue of philosophical psychology—real-time honesty based on a teachable technique.
Indeed, I cannot find anything anywhere in world philosophy, religion, or literature that provides a teachable technique for attaining real-time honesty with another person.
I also do not quite understand how this could be.
For many centuries human beings have thought about life but no one has come up with a technique like FIML?
How can that be?
I do not see a technique like FIML anywhere in the history of human philosophy nor anywhere in modern psychology.
The importance of a “good friend” who does FIML with you cannot be overemphasized because it is only through such a friend that you can discover where your premises about them are right or wrong, where your thoughts about them are valid or not, and through those discoveries where your mind itself is arranged soundly or not.