Inflation is a lack of goods for a given demand though. Ie if we can flood the world with cheap goods then inflation won't happen. That would make practical UBI possible. To some extent it has already happened.

My intuition, based on what I know of economics, is that a UBI policy would have results something like the following:

* Inflation, things get more expensive. People attempt to consume more, especially people with low income. * People can't consume more than is produced, so prices go up. * People who are above the break-even line (when you factor in the taxes) consume a bit less, or stay the same and just save less or reduce investments. * Producers, seeing higher prices, are incentivized to produce more. Increases in production tend to be concentrated toward the things that people who were previously very income-limited want to buy. I'd expect a good bit of that to be basic essentials, but of course it would include lots of different things. * The system reaches a new equilibrium, with the allocation of produced goods being a bit more aimed toward the things regular people want, and a bit less toward luxury goods for the wealthy. * Some people quit work to take care of their kids full-time. The change in wages of those who stay working depends heavily on how competitive their skills are -- some earn less, but with the UBI still win out. Some may actually get paid more even without counting the UBI, if a lot of workers in their industry have quit due to the UBI, and there's increased demand for the products. * Prices have risen, but not enough to cancel out one's additional UBI income entirely. It's very hard to say how much would be eaten up by inflation, but I'd expect it's not 10% or 90%, probably somewhere in between. Getting an accurate figure for that would take a lot of research and modeling.

Basically, I think it's complicated, with all the second and third-order effects, but I can't imagine a situation where so much of the UBI is captured by inflation that it makes it pointless. I do think that as a society, we should be morally responsible for people who can't earn a living for whatever reason, and I think UBI is a better system than a patchwork of various services with onerous requirements that people have to put a lot of effort into navigating, and where finding gainful employment will cause you to lose benefits.