In The Meaning of Life: A guide to finding your life's purpose, I explain in detail how life works and how you can use that information to figure your purpose out for yourself. However, it doesn't mention another major question, "Who am I?" Because I wanted to keep the book focused on helping you figure out your journey, I didn't spend any time connecting who you are to why you're here. Because many people who ask why they're here often begin to question who they are, let's explore that connection and discuss how you might find out about yourself in your striving for meaning and purpose.
For some background to those who are new to this unifying theory of meaning, the "Why am I here?" question is answered quite simply: you are here to grow through life experience, and you grow optimally by making deliberate choices to focus on what you want, believe that you can attain your goals, pursuing them ethically, getting/giving support where necessary, and listening to your emotions to see whether you're on the right track or not. That is how you find your meaning in one (long) sentence. Those same concepts can tell you about yourself, but let me explain this in a more direct and logical way.
"Who am I?" is a philosophical question about your characteristics, values, interests, beliefs, behaviors, relationships, and achievements that combine to form your sense of self and others' perception of you. When someone asks you who someone else is, you define them based on these properties. Here are examples by each way you define someone:
So, what do these attributes mean for you, and how do you tie them to the eight core components of the meaning of life? Well, there is a quick exercise for you to do to get started on defining yourself, and then a way to leverage this to figure out what you want to be:
To get started in understanding who you are and who you want to be, use these attributes to define your current state and your desired future state. Remember, you don't have to let external factors or other people define you, but using what you can easily recall is a good way to get yourself started in understanding yourself. Let's take a hypothetical example of a teenager who is trying to find himself as he goes to college:
You can see from the above that you can learn a lot about someone with just the short descriptions of each of these attributes. Yes, you may be more than the sum of your parts, but it's a good start to understanding yourself and feeling a little less lost. Once you complete this exercise for yourself, all that's left to understand whether this self-assessment accurately reflects who you really are is to examine your emotions to see whether it feels right to you.
(Note: people can use the above attributes to judge someone, but people are always making judgments, so a person can only control themselves and not let others define them. The goal here is not self-judgment but rather understanding what makes someone who they are.)
Once you've done that, you can do the same for a desired future state of who you want to be. Let's use the same hypothetical person above and map out a future state for him:
Here, you can see from this example of someone's gradual transformation from where they are to where they want to be that you're trying to stay roughly the same person but make progress over time in what you know, what you do, who you are, and what you accomplish. Your degree of growth and transformation is up to you, and you'll know whether you're on the right track if you're happy and fulfilled with your life.
This is where the "Who am I?" question intersects with the "Why am I here?" question. The meaning of life is growth, and growth is the transformation of yourself from a current state to a future state. For you to have a purpose, you do have to have at least some sense of yourself given the above attributes and what, therefore, you will spend your time doing. To figure out yourself, you can start by identifying your characteristics, relationships, behaviors, and achievements so far in life (if you can't think of the latter, give yourself more credit). These are either past events or self-evident current circumstances, so you can easily write them down. Then, identify your desires, beliefs, and values. What you want, believe, and value will determine your goals, ethics, and behaviors moving forward, so you have to try to understand them. This process can be difficult, and you might not like everything you identify, but it's important to introduce yourself to...yourself so that you can begin to understand what matters to you.
Once you've gotten that, the transition from understanding yourself to understanding your purpose is simply the act of defining who you want to be (i.e., your desired future state) and then figuring out what to do to get there (i.e., your purpose). If you've done the above current-state and future-state exercises for yourself, all that's left is to create a third list that takes that information and determines what growth you need to seek to become the person you want to be, the experiences you need to pursue to attain that growth, and then make sure that you make deliberate choices and get the support you need to attain them. Make sure that your desires tell you that you really want that future state and that your beliefs and ethics are ones that will be optimal for you to be able to attain it. As always, your emotions will tell you how you're doing.
When you're done with those three exercises, you will have a better (if not clear) understanding of who you are, who you want to be, and why you're here. Figure that out, and you will not only know what you're about but will also feel a greater sense of self-assurance and comfort with yourself.
If you can't complete these exercises all at once, you can always take time to think about it, do research, or have new experiences that help you learn more about yourself. Your purpose and self-understanding is constantly changing and evolving as you have new experiences and your desires and beliefs change, so embrace the uncertainty and change. You don't have to figure it all out—as long as you're directionally correct with your next steps, you'll always be making progress. And progress—aka growth—is the whole point of having a personal identity and life purpose.