Ancapology rests on the recognising negative rights (the right not to have something inflicted upon you, such as murder), but not positive rights (entitlements that place a burden on others, such as healthcare). That’s perfectly legit. Contrary to ancap misconception other ancoms don’t recognise universal positive rights either, but may choose to extend those within their own communities.
Ancaps make a big deal about “the world doesn’t own you anything commies”. They also make a big deal about their “property rights”. In the ancap mindset property rights are negative rights, the right not to have something taken away by force. Realistically that can only apply to property actually in the owner’s possession, since upholding abstract property rights (the right to stuff that isn’t occupied or used by its owner) places an unreasonable burden on others.
Where a third party has voluntarily entered into a contract with the owner, then breaching said contract would be no different to stealing, but it would not be altogether unreasonable to challenge the validity of any such agreement that was negotiated using leverage.
Negative rights are completely inapplicable whereby a third party has not entered into any contract with the owner, and is able to peacefully establish possession of the property in question. Ancaps will of course insist on hypothetical examples of this, so lets run through some:
1. Imagine someone left their home to visit the store, and returned to find a third party had invaded it. Merely entering a house does not actually constitute establishing possession of it, since the community as a whole is extremely unlikely to view an intruder as the rightful occupant, because to do so would also be to legitimise theft.
2. But what if the house was totally isolated rather than part of a community? Ok, so let’s just set aside how unusual it is for any house to be absolutely isolated, and also assume that someone would want to steal an isolated house. In the absence of the state that becomes the owner’s problem. Sorry ancaps, the world isn’t obliged to safeguard your property.
3. But what if someone went on a long vacation? Well “doh” then arrange for a family member, neighbour, house sitter, or security firm to look after your property. Aside from anything else it would be foolish to leave a property vacant and unattended for an extended period, since all manner of things can go wrong including ingress by nature. Once again, the world isn’t under any more obligation to safeguard your property than it is to provide you with medical care.
The ancap position is that everyone else is somehow obligated to recognise and uphold abstract property relations. We aren’t, and establishing any such positive right would therefore necessitate force. Ancaps resort to a sleight of hand, attempting to occlude this by disingenuously lumping both intuitive property and abstract property under the catchall of “private property”, and insisting that it’s all covered by negative rights. It isn’t.