he had to give us free will

It depends on what you mean by free will, but there are many sound arguments that suggest we don't have it. In fact, numerous experiments have been conducted that can predict what you're going to think a couple of seconds before you think it.

You can only process within the limitations of your brain chemistry or choose between the options you compute, or those your environment presents; if you were to swap atoms with someone else it's difficult to envisage how you would still be you, or that some mysterious "ghost in the machine" would remain.

Most neuroscientists seem to gravitate in this direction (denying the existence of free will), as well as the majority of physicists. There are also numerous examples of brain tumours and other physical ailments drastically affecting human behaviour.

Free will is a very persuasive notion; all of us feel like we have control but when you think to the depths of this debate, it's difficult to believe the notion that we're the originator of our own thoughts or that there's some mysterious "ghost in the machine".