In all my posts about senses, I've been discussing our senses as an awareness of different properties of the universe. We get feedback from the world around us, and make choices based on that feedback. We get feedback from our memories, from our sense of sight, from our brain's pattern recognition, from our rational abstract thoughts, from our current emotional state (run! I'm afraid of the tiger!), and we make a choice based on that feedback.
Our choices are actually based on all that feedback combined with our DNA, in addition to things such as our feeling of an ingroup versus outgroup, and our moods. Our moods change our goals. When you're in a bad mood, you may still be just as rational as if you are in a good mood, given your different goals.
A bad mood may give you the desire to stay in your room and shut out the world. A good mood may give you the desire to laugh with friends. Your moods are then filtered through your personality and result in a given decision. Your personality will determine if you calmly shut the door or slam it when someone hurts you emotionally. Where you decide to go to dinner with friends when you're in a good sociable mood; what sort of ambiance you prefer. But ultimately, your mood is going to subtly influence every decision and action you take.
Creating a model of our psyche could look something like the following:
We have a range of possibilities available to us, but those will be affected by, and therefore limited by, our mood as well as our personality.
Each of our senses simply gives us additional feedback about how our decisions changed the universe (did we catch the ball?). In addition, our senses also give us information on the current state of the universe (such as our own levels of hunger) in order for us to properly exert our will to achieve our goals.
We see pixels on a computer screen through the sense of sight and know the price of a given stock. We use our sense of memory to remember our investment plan. We use our sense of pattern recognition to determine probable financial results for ourselves. Our chemical makeup based on our DNA may affect our mood (whether we're extremely competitive and likely to take risks or not), and the other events in the day (taken in by our senses) will also affect our mood. We eventually arrive at a decision regarding whether to buy a given stock and repeat the process.
At the core, we are simply using our senses as input, using our brain to give us possible outcomes (which include not just which is "best" but also how we'll feel after each decision), make a choice (this is key; I don't believe in determinism), and then direct our body to implement our output decision.
This is the purpose of our senses. To allow us to be aware of the feedback from the universe to make different choices. Our senses are filtered through our moods to arrive at a decision.