Q:

Can I call behaviors methods directly without eventproxy?

I'm searching for alternative ways to call a method defined in Marionette's behaviors from inside a view.
For sure there is the eventproxy but maybe it's more intuitive to call the method directly like: 
view.behaviorsMethod();

I could assign it like:
view.method = behavior.method;

I could check for reassignment because it'll maybe lead to unexpected results for others: 
view.method = (view.method !== undefined ? view.method : behavior.method);

But this doesn't seem to be an elegant way.

A:

The answer to your question is you can not directly do so, but there is always a way. 
you can do it using _.invoke(this._behaviors, 'yourMethodName') but I will discourage using it 
since 

_behaviors is a private variable of the Marionette.View class and it's name can be changed or it can be dropped in upcoming versions
You will have to set context for the method as _.invoke will not set
the context of the method to proper this.

if you can set the context properly then this will work for you.
as suggested by @ThePaxBisonica in comment 
I will suggest you to go with a mixin pattern from which you can extend both your behavior and view and you will not have to set any context and do not have to worry about the _behavior private variable
as
var mixin = {
    behaviorMethodWhichYouWantToCallFromView: function(){
           alert("mixin method");
    }
}

var behavior = mn.behavior.extend(_.extend(mixin, {
    //actual behavior code remove the method as behavior will get it from mixin
}))

var view = mn.view.extend(_.extend(mixin, {
    //actual view code remove the method as behavior will get it from mixin
}))

Hope it helps.
I know this is bit long approach.

