If you're born tabula rasa and everything you know is learnt, then everything your senses know came from an external object which exists independently of your senses.
Are we going to do Kant vs Nietschze until the end of time?
> If you're born tabula rasa
There's lots of evidence that just isn't so. If nothing else, we appear to be equipped with minds which are better suited than random chance to build a "meaningful" model of the world around us.
The solar system existed before our senses received the information that it did. Insurance companies scan for pre-existing medical conditions before they discover them in new patients.
Why would you seek new objects, if there were not objects out there to find?
You have to sever all relationships to un-sensed, but knowable objects, to live only in the senses. That kind of reduction is too much to ask.
However, I'm not saying that things don't exist, it's that they do exist but not independently of the conscious agent that has the experience of them. The universe and the thinking agent that is currently perceiving that universe, come into existence simultaneously, in the act of perceiving/thinking.
The mind arises out of the necessary universe that is required for a mind that observes it to exist.
There could be infinite of other universes (or other things "out there" i can't experience), but those claims makes no sense since because for something to exist it must have a conscious agent experiencing it as existing. There can't be a universe in the void, simply rocks. Even "rock" is something that is defined by thought and can't exist independently of it.