No but physics did teach me well that observation is king, and if your explanation fails to explain what I've observed then you must be wrong. The majority of homeless are not mentally ill or addicts. What I observed is that the way people get along is strongly influenced by their environment they are a part of. Were you to go from town to town and from situation to situation human nature and the people you would meet may suprise you. Ther is a reason that term "brother" gets tossed around- it is not just washed up bum talk. Even the addicts will show a different side of themselves if a community is allowed to take root around them. THAT right there says you have not identified a true fundamental factor of causation, i.e. drugs did not cause it, rather something caused the drugs which helped cause the homeless situation. Unfortunately we live in a society where people are outside broken up or inside separated. You've spent much time and effort normalizing fitting into this reality.