Erwin Schrödinger

"One can even set up quite ridiculous cases. Imagine an experiment that will not be carried out until the year 2000, in which a cat is penned up in a steel chamber, along with the following device (which must be secured against direct interference by the cat): at the heart of a Geiger counter, there is a tiny bit of radioactive substance, so small that perhaps in the course of the hour one of the atoms decays, but also, with equal probability, perhaps none; if it happens, the counter tube discharges and through a relay releases a hammer which shatters a small flask of hydrocyanic acid. If one has left this entire system to itself for an hour, one would say that the cat still lives if meanwhile no atom has decayed. The psi-function of the entire system would express this by having in it the living and dead cat (pardon the expression) mixed or smeared out in equal parts."

— from Die gegenwärtige Situation in der Quantenmechanik, 1935

"The scientific picture of the real world around me is very deficient. It gives a lot of factual information, puts all our experience in a magnificently consistent order, but it is ghastly silent about all and sundry that is really close to our heart, that really matters to us. It cannot tell us a word about red and blue, bitter and sweet, physical pain and physical delight; it knows nothing of beautiful and ugly, good and bad, God and eternity. Science sometimes pretends to answer questions in these domains, but the answers are very often so silly that we are not inclined to take them seriously."

— from Mind and Matter

"This life of yours which you are living is not merely a piece of the entire existence, but is in a certain sense the whole; only this whole is not so constituted that it can be surveyed in a single glance. This, as we know, is what the Brahmins express in that sacred, mystic formula. Tat tvam asi—this is you. Or, again, in such words as ‘I am in the east and in the west, above and below, I am this entire world.’"

— from My View of the World