Argument from Reason?

[Barefoot]

But for a rational inference to be made, these must be true. Doesn't that mean science presupposes determinate meaning?

1. States of mind have a relation to the world we call intentionality, or aboutness. The intentionality I am referring to is propositional in nature.
2. Our possessing this kind of intentionality means that we are capable of having, entertaining, believing, and desiring states of affairs propositionally described. 
3.We recognize the propositional contents of our thoughts. Thoughts and beliefs can be either true or false. Human beings can be in the condition of accepting, rejecting, or suspending belief about propositions. 
4. Logical laws exist
5. Human beings are capable of apprehending logical laws. 
6. The state of accepting the truth of a proposition plays a crucial causal role in the production of other beliefs, and the propositional content of mental states is relevant to the playing of this causal role. 
7. The apprehension of logical laws plays a causal role in the acceptance of the conclusion of the argument as true. 
8. The same individual entertains thoughts of the premises and then draws the conclusion. 
9. Our processes of reasoning provide us with a systematically reliable way of understanding the world around us.