As for a $4k tax being "crippling to a good chunk of them" -- no, you misunderstand the nature of BI. If we're paying $20k worth of BI in this scenario, then the mean income should be about $40k (since a good level for BI -- in basically any economy -- is about 50% of the mean). We could then support a flat $20k/person BI with a flat 50% earned-income tax. This means that the payments and receipts, per person would look like this:

  Income    Tax   +BI    Net    Effective tax rate
  $0       -$0    $20k   $20k   N/A
  $10k     -$5k   $20k   $15k   N/A
  $20k     -$10k  $20k   $10k   N/A
  $30k     -$15k  $20k   $5k    N/A
  $40k     -$20k  $20k   $0     N/A
  $50k     -$25k  $20k  -$5k    10%
  $60k     -$30k  $20k  -$10k   15%
  ...
  $100k    -$50k  $20k  -$30k   30%
  ...
  $1,000k  -$500k $20k  -$490k  49%

Explain why after spending 10 years in school my tax burden should increase by 30k (making it an effective 60% rate not counting 10% sales tax in CA) to give to able bodied people who choose not to get off their ass. I guarantee you society is better off letting me keep what I earned rather than giving it to a completely untested individual. I didn't work my ass off for you.

PS: I hardly ever meet any of those "able bodied people who choose not to get off their ass" - they mostly show up in discussions like these - and I suspect they're a tiny minority. Let's not adjust policies to punish that tiny minority if, in the process, everybody else gets punished too.

How do you arrive at this?

I don't see where you're getting that. Presuming the numbers haven't changed since you commented, it looks to me like taking away half of every dollar earned.

We already do this with income tax forms.

Furthermore, a 4k tax on 250M of the U.S. could be crippling to a good chunk of them. If your true point is redistribution of wealth, our tax system already does that and can do it more. But that's a different discussion..

That's what this is. It's very similar to Milton Friedman's negative income tax bracket.