When someone mentions science, what's your immediate reaction? Do you rejoice that facts will ensue, and conclusions will be moderate and peer-reviewed? Or, do you start to glaze over, already knowing that no matter what someone else tells you, deep in your gut you know what the right answer is? Is the best art made when you're not thinking at all? Are there any secret formulae or rules to follow?
The two extremes
It's fair to say that most of us will fall somewhere in between these two extremes, knowing that science can prove certain things that we might never have known otherwise (pi, speed of light, gravity, atoms, why red and blue make purple, etc) and that some things don't feel right or look right without really knowing (or needing to know) the reason behind it.
The thinking part
Generally speaking, the science part of our brain (the rational, logical, thinking part) is located in the pre-frontal cortex. This is the more recent addition to our brain structure that has allowed us to make the huge creative and scientific leaps we've seen in (relatively) recent human history - think 10,000 years or so. It takes its time to engage and can be the reassuring, calming voice we need to hear. It can set up an experiment, control variables, and assess success.
Fight or flight
The amygdala is the "oldest" part of the brain and deals with the fight or flight response; our fear and basic emotion centre. It is in charge of working out what counts as a threat and what doesn't. If you're feeling stressed, chances are this part of the brain is working hard to keep you alive and out of harm. This part often kicks in immediately before your slower, thinking part of the brain, has a chance to come online and see what all the fuss is about. Great if you're dodging a flying ball, less helpful if you're checking your emails. It's not always about fear, either, it can be food, sex, water, etc - anything associated with your basic human survival.
One at a time, please
What's interesting is that these two parts of the brain don't like working at the same time. If your fear response is engaged, you'll find it very difficult to think rationally. Yes, it's only a phone call to another human being, but if I get it wrong... disaster! Part of the challenge can be in quietening the part of your brain that's flying off the handle - gently, coaxing it down off the ledge. One way to do this is through meditation, another is to write your thoughts down, or even talking it through with another person. These engage the higher part of your brain, and calm the stress response of hormones in your body. Creativity is best approached from an angle of curiosity, and not fear.
Well, that's all great, but what's that got to do with art?
You'll find that when you're making art (or creating anything of note, for that matter) that you flit between these two states. Art making requires that you use both of these areas of your brain: the rational side will understand the art scene you're in, how it relates to culture and where you find yourself within it. It will help you plan the size of your painting, how to mix the paints to create the colours you want, and why things might not be working in terms of layout and composition.
Silencing the critic
Your intuitive part of the brain needs to have a say though, otherwise your art will feel flat and lifeless. This doesn't mean it needs to be a messy abstract, just in tune with that gut level of emotions. Other people are very good at being able to see where you've had fun, got passionate, let go, allowed the expressive part of yourself to come out. The little bits that you included because you just wanted to. It's the difference between a Botticelli and a paint by numbers - there's life, soul and energy in the work.
Use your taste
This bit taps into your taste, what you feel goes together, what colours attract you, and how you want your work to feel when it is viewed. You have to silence the thinking critic when you create, knowing that this time is for doing, not judging. It will allow you to get into the flow state and is probably the most addictive, enjoyable part of making art.
It's time to let science and intuition work together at what they're best at - this is where depth and power lie in your work. Relying purely on one or the other means you're only seeing half of the picture, and no artist wants that.