Some people have criticized consciousness-altering drugs on the basis that they effect our perception of reality, but what is actually wrong with wanting your perception of reality to be altered? Don't all forms of art, music, theatre, etc. present us with a transformed version of reality? And in other sense, isn't the hallucinatory experience of a drug-user just as valid and genuine as the sober experiences of another person. Is it fair to say that the sober person's experiences are in some way "more real"?

You are right that we seek to alter our experiences in the world with the use of art, music etc. And insofar as drugs attempt to alter experience and give us new experiences, I agree with you that there is nothing wrong with them. More than that--drugs may be valuable because of the aesthetic and other pleasures they can produce. However, I think those who worry about "altered perceptions of reality" may be concerned that the drug user may be evading responsibilities when they get high ("I don't need to do my work, take care of my kids etc. because life is more interesting on LSD"). Or the drug user may behave when high in a way which does not cohere with his/her values. That is, the objections to drugs seem to me to be ethical rather than epistemic. In addition, the health risks (psychological and physical) of consciousness-altering drugs should be taken into account (another ethical concern). The word "real" is not helpful in this discussion, because it is used to mean so many different things (e.g. what actually exists vs. what matters).

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