While sometimes we automatically make logical inferences without paying any attention to the process, usually one has to consciously decide to think something through. This is especially true of complex issues.
It is quite likely that we all like to think of ourselves as logical beings at some level, even those who pretend to an illogical style. I suppose this is because we all do think from time to time, and that our culture values people "making sense".
We certainly are capable of ignoring even things we have carefully thought out, however. While other aspects of our mind may intrude and override our ability to identify our self with our truest spirit, the intellect is the easiest tool we have to ignore.
Contrast to the connection between the conscious self and the unconscious!