Models
Models are descriptive theories, they "represent" some system or aspect of the world.
They are usually composed of:
You can sometimes "model" something by just dumping every conceivable piece of information about it, but this is usually not very practical or elucidating. What you want is a method of extrapolating from a smaller amount of information. This tends to come at the cost of accuracy/specificity, resulting in a balancing act.
Each model has a domain, that is, a context of applicability, the particular system or class of systems it seeks to describe. Economic theories cannot explain star formation, for example.
You may also have multiple models for the same system, but at different "scales", by coarse-graining. The two models (say, A and B) will encode the state in two different ways, and you can come up with a mapping from one to the other, to "translate" between them. If many states in model A are mapped onto the same state in model B, then A is "fine-grained" and B is "coarse-grained" (relative to the other, that is). That means that B is "large-scale" and A is "small-scale".
- A way of encoding the state of a system, with respect to some parameters (time, for example)
- A function predicting how the state changes as those parameters change
- A function predicting how the state changes as those parameters change
You can sometimes "model" something by just dumping every conceivable piece of information about it, but this is usually not very practical or elucidating. What you want is a method of extrapolating from a smaller amount of information. This tends to come at the cost of accuracy/specificity, resulting in a balancing act.
Each model has a domain, that is, a context of applicability, the particular system or class of systems it seeks to describe. Economic theories cannot explain star formation, for example.
You may also have multiple models for the same system, but at different "scales", by coarse-graining. The two models (say, A and B) will encode the state in two different ways, and you can come up with a mapping from one to the other, to "translate" between them. If many states in model A are mapped onto the same state in model B, then A is "fine-grained" and B is "coarse-grained" (relative to the other, that is). That means that B is "large-scale" and A is "small-scale".
Goals
A goal is a chosen "win state".
It is not objective, in the sense that it is not true or false.
It is something you want.
Goals can be thought of as functions of the state of a system. What they return is usually either a boolean, describing whether the goal has been achieved, or a value, describing "how well" it's been achieved. Tonight, my goal may be to fall asleep. That's a boolean, I will have either succeeded or failed. Alternatively, I may want to fall asleep as early as possible. That is a value, a number, it can be measured on a scale, and I have a preferred direction I want to travel in, rather than a specific outcome.
Goals can be thought of as functions of the state of a system. What they return is usually either a boolean, describing whether the goal has been achieved, or a value, describing "how well" it's been achieved. Tonight, my goal may be to fall asleep. That's a boolean, I will have either succeeded or failed. Alternatively, I may want to fall asleep as early as possible. That is a value, a number, it can be measured on a scale, and I have a preferred direction I want to travel in, rather than a specific outcome.
Strategies
Strategies are derived from the synthesis of a model and a goal.
They are plans of action, proposing how one can personally tweak the parameters of a particular model to achieve or move in the direction of a particular goal.
This is, I think, what a prescriptive theory usually is.
It tells you what to do, in order to achieve something.
Some prescriptive theories do not have clear goals. They tell you to do something, without telling you what you're trying to achieve. This is not a strategy; rather, it is what I would categorize as nonsense.
Some prescriptive theories do not have clear goals. They tell you to do something, without telling you what you're trying to achieve. This is not a strategy; rather, it is what I would categorize as nonsense.