Now secondly, obviously the premise is also completely untrue and almost impossible to achieve: The artist did have something in mind when painting these pictures: to paint pictures where only the viewer is meant to decipher the meaning while the artist themself has nothing in mind. He or she also did paint something aesthetically pleasing so there seems to be a lot of intention on that part as well. Painting something without any intention at all seems almost completely impossible to me. (Maybe you could trick somebody else into painting something without them knowing about it – but even then you are still the artist with an intention).
Finally I wanted to address the criticism by some other comments that art critique and galleries are always looking for an artistic intention even if there is none. I don't think that's completely true – I have seen plenty of exhibitions where it is explained that the artist "was just experimenting with form/colors".