Because even when you fire electrons one at a time through 2 slits, the same wave pattern is seen to emerge. It appears as though a single electron explores ev

Because even when you fire electrons one at a time through 2 slits, the same wave pattern is seen to emerge. It appears as though a single electron explores every one of its options before it chooses a single route. The exploration process seems to leave footprints in a universe we can't see which causes the electron to behave strangely.