In his paper, "The MAGNETIC FIELDS of Uranus and Neptune", at http://milesmathis.com/uran4.pdf Mathis said the existing tilts of the planets "requires that we have some original tilted planet or planets whose tilts were not caused by other planets, but that only means we need one tilted planet in the past to enter the Solar system and cause a line of instability. I don't see that assumption as a problem."