There are hierarchies of minds. A horse is smarter than (I don't know) a slug and a pig (so I'm told) is smarter than a horse, and a great ape is smarter than anything we're aware of on the planet apart from ourselves. I'm leaving whales out of the equation because who knows?
Why should the hierarchy of minds stop with us. Do we really represent the furthest and highest reach of intelligence? If there existed greater minds than ours would we recognise them? Would they- given the mistrustful, violent nature of the human being- care to be recognised by us?
If they showed up, mightn't we go, "Angels! Aliens! God Almighty!" And go cringe in a corner? And when the experience was over mightn't we go, "Well that was a weird dream!"?
We think we have minds that are capable of understanding anything and everything, but perhaps we don't. For instance we know- as a matter of science not speculation- that there are many more dimensions to the universe than the three we experience- Height, Breadth, Depth- and the fourth we can't really get our heads round- which is Time. These others are closed to us. But there may be intelligences to whom they are open.
Perhaps we're no more capable of understanding the universe than a horse is capable of understanding a wheelbarrow.