Sci-fi story

An alien has just visited Earth and is reporting what he saw to his commander:

"They are made out of meat"
"Meat?"
"There's no doubt about it. We picked several from different parts of the planet, took them aboard our recon vessels, probed them all the way through. They're completely meat."
"That's impossible. What about the radio signals? The messages to the stars?"
"They use the radio waves to talk, but the signals don't come from them. The signals come from machines."
"So who made the machines? That's who we want to contact."
"They made the machines. That's what I'm trying to tell you. Meat made the machines."
"That's ridiculous. How can meat make a machine? You're asking me to believe in sentient meat."
"I'm not asking you, I'm telling you. These creatures are the only sentient race in the sector and they are made out of meat."
(It goes on as the commander inquiries whether that race couldn't have the attributes of other ones they are acquainted with.)
"No brain?"
"Oh, there is a brain all right. It's just that the brain is made out of meat!"
"So...what does the thinking?"
"You're not understanding, are you? The brain does the thinking. The meat."
"Thinking meat! You're asking me to believe in thinking meat!"
"Yes, thinking meat! Conscious meat! Loving meat. Dreaming meat. the meat is the whole deal! Are you getting the picture?"

Terry Bisson (cited in The Mysterious Flame, by Colin McGinn)