Re: should you smoke marijuana on your aikido journey
In a word no.
Not that I have anything against Marijuana, I just think it is a recreational thing. I certainly would not want to practice with anyone who is high. As to off the mat....Well "pot heads" are less likely to get into bar fights than drunks, but experience has taught me that any kind of intoxication can interfere with proper judgment (discernment) and can cause the trust of the individual to come into question. Nobody with slurred speech has ever made a persuasive argument for peace.
In general I have found that for someone not well versed in a Shamanic tradition and experienced with alternate states of mind brought on without intoxicants will not gain anything using them in their practice. In the cultures that use peyote and other hallucinogens, even mild ones like pot, restrict them only to well trained shamans. There are good and valid reasons for this. We should respect those cultures and their reasoning. They have had thousands of years of experience with this stuff.
Keep a clear head and things will appear much clearer to you.