Short story about a man who travels to another planet via astral projection, where he encounters an alien intelligence that exchanges minds with him

Question

Looking for short story read in the '60s.

In the future, space exploration uses a sort of astral projection. The traveller is in the lab and hooked up to monitors, but they don't allow real-time analysis. Just as his trip to another barren world ends, he encounters an intelligence which says "with you I exchange my mind". In a flash the trip ends and he is "woken" in the lab. They ask if there was anything of note and he says not and goes home.

He soon becomes aware of what happened and realises it's monumental, as the mind he exchanged with had been collecting minds for eons and he has them all for sharing only his. He's reluctant to admit to the authorities and realises they will soon finish the analysis and come after him......

Answer 1

This is Clifford Simak's novel "Time is the Simplest Thing" (1961).

Excerpt of plot synopsis from Wikipedia:

Shep Blaine is an explorer working for Fishhook, an organization exploiting paranormal powers to explore planets around other stars. Because of anti-paranormal prejudice in the US, Fishhook operates in northern Mexico. Explorers spend time in "star machines", which are boxes shaped and decorated to stimulate the mind to leave the body and explore the universe. They are accompanied by a small machine that can record experiences and gather physical samples. Some explorers have returned with minds affected by what they encountered. Those explorers have disappeared and never been heard from again.

Blaine returns from one expedition having encountered an intelligence that looks like a large pink blob sitting immobile in a room open to the sky. The blob greets him telepathically with the message "Hi pal! I trade with you my mind." Blaine immediately feels the alien mind alongside his own. Returning to his body, he knows he must get away before the recording of his trip is checked.

One of my all-time favorites. The piece of the story you describe, and the excerpt above, are all just an intro to the plot proper. Most of the book deals with a movement to set up a sort of underground railroad, or in this case a trans-spatial railroad, to deliver the persecuted minority group ("parries") to a refuge.