Free will can exist in the same way God can exist. At least with our current understanding of the universe, we lack a falsifiable test to disprove either. Howev

Free will can exist in the same way God can exist. At least with our current understanding of the universe, we lack a falsifiable test to disprove either. However, there is also no evidence to support the existence of either with any greater certainty than the claim that there is a teapot orbiting the sun somewhere between the orbits of Earth and Mars. You are welcome to believe in God, orbital teapots, and/or free will, of course, so long as your belief doesn't lead to actions which create a negative imposition upon others. Sadly, that is all too common, and far less welcome, in my eyes.