What are M'zikin?
The third consideration, mentioned in the previous post, m'zikin, deserves some more explanation. I said that m'zikin are unseen, dangerous forces. I do not know what exactly chazal believed these forces were. What does seem clear is that they believed they were unseen and could cause one harm. This idea is not as foreign as it seems. Everyone is familiar with the effect that different places can have on one's mood or behavior. Being in prison might make a person feel aggressive, defenseless or combative. Being in a court might make a person feel guilty, self-conscious or uneasy. Being in a classroom might make a person feel constricted, boxed in or bored. Being in a bar might make a person act more bold or wild or worse. Of course, a place could have a positive effect on someone - like the way one might act in synagogue (we hope) or the study hall. Finally, being in a hurba might make one feel uneasy, depressed, sad about what happened, scared.
It is clear that different locations exert a kind of force on a person and can make one act or feel a certain way. We, of course, would attribute this to internal psychological forces that are set in motion by the environment. However, it is just as true to say that the environment is causing the change in behavior. I do not want to be anachronistic in my interpretation and say that chazal used the word m'zikin to refer to psychological forces. On the contrary, I think there is something to be learned from viewing m'zikin as an external force (as opposed to internal psychological forces). The view that the only thing that moves us to action is some internal psychological force makes us feel that we can in some way control those forces. After all, if they are forces that are inside us then shouldn't we be able to control them? This, however, is not the case. Psychological forces can be just as outside our control as external environmental forces - we often delude ourselves into believing that because these forces are internal we can control them. More often than not, the only way to protect ourselves from these forces is to avoid those situations (or places) that bring them out.
Why does the gemara say that in the presence of two people there is no fear of m'zikin. Quite possibly because the presence of another individual keeps us grounded and objective. As long as there is another observer we keep ourselves in check and are not as influenced by our environment. Think of the difference between being alone in a house in the middle of the night as opposed to having someone else around to keep you company. The situation that was scary when alone feels comfortable and safe with the presence of another.