What's Wrong With Being a Loner?

ג,ד/ה:  חנניה בן חכינאי אומר, הניעור בלילה, והמהלך בדרך יחידי, והמפנה ליבו להבטלה

הרי זו מתחייב בנפשו.

Chanina Ben Chachinai says, one who remains awake at night, and one who walks a journey alone and one who empties his heart from thought, is responsible for his loss of soul.

The obvious question may be posed: what has a fellow done by pulling an all-nighter, by journeying alone or by vegetating, is there an inherent sin within any of these habits?

The last statement, with its clearly negative connotation, is easily understandable. Perhaps since one is consciously thinking about nothing one is simply put "wasting his time". Wasting one's time is obviously not commendable

The former two however, seem to be neutral points. They both are acts of being a loner, but what's wrong with doing things on one's own, be it travel or be it one's waking hours?

The answer is that being a nocturnal loner or alone on the road allow a person to be in a situation where temptation lurks and at the very same time being without the inhibitions that society places on them. Many temptations are hard to resist. Luckily, we often abstain due to social norms. It is most likely that the latter point of the mishna is of a similar vein. The human mind is powerful and consequently will always be active. One who consciously is thinking of nothing is apt to contemplate sin. Sin is tempting, and if there are no productive thoughts to impede it,  the superficial high of sin will almost certainly find its way into one's mind.

Chanina Ben Chachinai is telling us that operating in a manner that is conducive to sin makes someone responsible for the eventual wrong doing.

This maxim epitomizes the theme of Pirkei Avos. Most of mishna is halachic dictums. These are legal clauses, details and overall law.  In all societies law and ethics remain two separate entities.  In Judaism law and ethics are nearly one and the same. Jewish law must have an ethical correlation. Jewish ethos are all deeply rooted in Halacha.