Are the words willpower and motivation different? And how can I distinguish between them?
I read about them in a book of building habits; it says motivation doesn't help to build a new habit while willpower does.
Yes, they are different.
Get motivated: increase your desire to take action.
Use willpower: force yourself to take action.
For example: You could be motivated to stop smoking for health reasons but, you must have the willpower to do so.
Further to Damkerng's comments, literally, "willpower" means the ability to control your mind and body in order to achieve something that you want/desire to do while "motivation" means only the reason, feeling, desire, or willingness to achieve something. In this way, motivation is part of willpower, but willpower isn't part of motivation.
I would like to mention an interesting saying that is quite relevent here.
"The spirit is willing, but the flesh is weak".
The saying is expressive that there is only willingness or feeling to do something, but the ability to do is lacking. If your spirit is willing (motivation) and you also have energies, skills, it becomes your willpower.
However, I think a psychologist can throw light on these terms in a better way.
A simple way to think of it:
Motivation is positive: it is your wanting to do something.
Will power is negative: it is your wanting to NOT do something else.
Motivation is out of your control; Willpower is the conscious force you apply, to try and choose which motivation you follow.
When motivations conflict, willpower makes the difference. For instance, I am motivated to go to the gym, because I want to lose weight. This motivation has strength 5. But I am also motivated to eat candy, because it tastes good. This motivation has strength 10. So I will eat candy. However, my willpower is strength 6. So I can apply my willpower to resist the temptation to eat candy, and because 5+6 > 10, I will then go to the gym. If my willpower is too weak (e.g. 4), then I give in to temptation, eat the candy, and feel bad about not having a strong enough will.
In Western philosophy there is the concept of the Will, the power or faculty of the human psyche that enables a human being to act purposefully. By our wills we act with a goal or purpose in mind.
Our motivation to act can be purposeful, driven by the will, but it need not be so. Motivation could be the result of subconscious factors, or of forces or influences acting upon us.
If you have motivation to do something, it means you have a good reason to do something. You know doing this will help you. You will probably want to do this.
A person might be motivated to quit smoking when they think about how much healthier they will be if they quit, or how much money they will save if they don't have to buy cigarettes anymore. However, just thinking about how nice it will be isn't enough to actually stop. You need something else to make you stop thinking and take action.
Having willpower means you are strong enough (mentally) to force yourself to do something, even if it's hard or you don't want to. It's hard to stop smoking, but with enough willpower, it is possible.
People with lots of motivation, but no willpower, probably will not be able to quit smoking. However, people with lots of willpower can make changes even with little motivation.
Motivation can be external. Willpower is always internal.
Let's say you're thinking of running a marathon. That's going to take some willpower. Your motivation may be internal: for example, it's something you always wanted to do. Or your motivation can be external: for example, people will donate money to your charity.
Motivation is interest; willpower is capacity to pursue interest.
A lot of good answers here. In addition to these (which all appear correct to me), I'd like to clarify that motivation can strengthen willpower, but nothing happens without willpower. This is hinted at in a couple of the other answers, but I think it deserves more attention.
For example, there might be many good reasons (going to work, hanging out with your friends, doing chores, etc. - i.e. significant motivation) for you to get out of bed in the morning, but if you have no willpower then you will be lazy and sleep in late. Inversely, if nothing special is happening today (it's a rainy Sunday, your house is clean, your friends are all busy - i.e. zero motivation) but you still want to get up and start your day early anyway, you'll do it under your own willpower.
Here, I believe, is where your confusion comes from: in the former scenario (insufficient willpower despite ample motivation) an ignorant observer might say you are simply unmotivated to get up (i.e. assuming you require more motivation), but it might just be that you're sick or depressed and therefore do not want to get up and face the world. Similarly, in the latter scenario (sufficient willpower despite zero motivation), the ignorant observer might marvel at your motivation to get out of bed so early, when really you might just be well-rested and uncomfortable languishing in bed even though there's nothing to do for the day.
To be motivated is to have a reason or want to do something. For example, if you had to wake up at 4:00 in the morning it would be more motivating to get up if you had fresh coffee. The coffee would be motivating. Whereas will power is having the choice to get up at 4:00 and to be willing to get up.
I would like to define Willpower as Self-Control.
Now, Self-Control work just like a muscle. If you use it everyday (70% of maximum). You have the can make it bigger for the future. In hard times when you have little or no motivation you can have the self-control to do something you wouldn't do.
Motivation, Works different. Some say that it's like double edge sword. Can work against you if you are solely depending on it. However, I'm firm believer that with Mindfulness and Hypnosis you can tap into the unlimited motivation.