If you have know argument on this point then you've conceded my point and the arguments over, determinism is contradictory. According to Locke, Berkely, and Hume one could never get beyond the world of perceptions in order to have access to the external world. And therefore any claim to know that an external world exists in a purely unjustified on Empirical means.
New thoughts can have antecedent causes.
The reason this is the case is because in order for your argument to even be considered one would need to have the ability to cognitively consider the points and then make a reasonable consideration for the truthfulness or falsity of the argument. However, if our thoughts are the result of chemical reaction in the brain then let's not fool ourselves, every thing we we know is the determined and therefore caused. So my belief that determinism is false and your belief that determinism is true are both the result of antecedent chemical reactions and not a logical reason. This is absurd. On a purely Empirical basis one can never get beyond the mental perception or representation caused by the external world, and as such, any descriptions made concerning the external world are unjustified.