Leary's impact was both good and bad.
Good: he alone caused many millions of people to partake in the LSD consciousness expanding movement. He made LSD seem like a wonder drug. Without his amazing and honest enthusiasm for LSD, many people would have never tried LSD, included SWIM. He also did some important work on psilocybin and LSD. And at the beginning he was a very positive figure.
Bad: he became reckless, got kicked out of Harvard for testing LSD on students, he later encouraged people to “turn on, tune in, and drop out”. That was the worst possible phrase he could ever have made popular. It sounded like he was encouraging people to become jobless drug addicts with no future! Of course that’s not the intension of the phrase, but that’s how most people interpreted it. The other thing that he did that was not good was to make it seem as though all drugs were good and that mind expanding drugs were the way of the future. He thought everyone should take mind expanding drugs. He ended up trying all sorts of harmful drugs. He became a drug addict. At the time he died of cancer he was hooked on pot, tobacco, and cocaine.
Leary was no Hofmann that’s for sure. Albert Hofmann lived a long healthy life. He never became a drug addict. He used LSD often though, but never in a habitual way. He was always respectable and never became reckless. Because of that, the positive messages that came from Albert Hofmann about how LSD can benefit a person, were never tainted. A professional could take Hofmann’s words seriously after many years. No so with Leary. After getting kicked out of Harvard and telling everyone to “turn on, tune in, and drop out” and dying of cancer, it’s hard to believe anything he said was ever valid. Its a shame. Leary did have good things to say at the beginning, but as soon as the drug addicts started hanging around Leary (they just wanted his LSD) he started to change, and lost all of my respect.
So there’s a bit of good and bad. Regardless of how reckless Leary became, he managed to get millions of people to use LSD and for that I’m eternally grateful. It was in fact his early books on LSD that got SWIM interesting in LSD in the first place. Without Leary’s early books, SWIM would never have tried LSD. NEVER. So Leary changed SWIM’s life for the better. It’s sad that drug addicts started flocking to him for a thrill. He ended up just being another drug addict.
Had he stuck to his own teachings of LSD and not gone down the path of self destructive drug abuse, likely leading to cancer, I think LSD would be seen in a much better light today. But because he did, now people can say, “LSD is a bad drug. It will mess you up. Look what LSD did to Leary. He was kicked out of Harvard, got addicted to drugs, later put into prison, and then died of cancer. Do you want that?”