I find that an interesting question. I see that on one side, to each person a "psychedelic" experience is unique in it's own right to them. On the other hand, you see a same basic trend, language or message which seems to be a part of something bigger than the drug, communicable only through understanding after the effects have worn off. The thing is that these lasting impressions can only feel like past dreams at times, perhaps driving the mind to seek that same sense of oneness, unity and flow. To actually stab at answering your question, I believe that psychedelics are tools, catalysts, keys, to many doors than open onto answers. I do not believe that psychedelics use our own, or the cosmic mind, but rather ask as windows through which we see doors of endless possibilities. Just a though.
I favor Huxley's idea that psychedelics open up closed doors in our perception. They increase the quality of awareness that is usually trapped by conditioning and stagnation, but inferior to meditation they add their own component of mind-funk and sensory distortions.