The word 'yoga' literally means 'union'. When you experience everything as one in your consciousness, then you are in yoga. There are many ways to attain to that unity within you. For example, hata yoga means you start with the body.
The body itself has its own attitudes, its own ego, its own nature. Apart from your mind, do you see your body has its own ego? It has its own attitudes. You have to succumb to it.
See, you say, "From tomorrow, I want to get up at five in the morning and walk on the beach." You set the alarm. The alarm rings. You want to get up but your body says, "Shut up and sleep." Doesn't it do it? It has its own way. So we start with the body. Hata yoga is a way of working with the body, disciplining the body, purifying the body, preparing the body for higher levels of energy.
All of us are alive; all of us are human beings, sitting here. But all of us do not experience life to the same intensity because our energy levels are not the same. Our pranic energies are not the same. Different people experience life in different levels of intensity.
For example, somebody sees a tree. A tree is just a tree. Most people don't even see it. Somebody sees the tree in more detail. An artist sees every shade of it. Somebody else not only sees the tree but also sees the divine in it. Everybody sees. But seeing is not the same because the level of intensity with which you experience life is not the same. So we start with the body because that is something that you know. The whole process of yoga is to take you from something that you know and take the next step into the unknown. If you talk about something that you do not know, either you have to believe it or disbelieve it, isn't it
Suppose I start talking about God. You either have to believe my God or disbelieve my God, which will only take you into flights of imagination, not into growth. So now I talk about the body. This is something that you know. You know you have a body. Now you take the body to its peak. Now I talk about the mind. That is also something that you know. Take it to its peak and then the next step. You can only grow by taking the next step, the next step, and the next step from where you are.
Realizing where you are right now and taking the next step is growth. If you talk about something not known to you, you are only going into imagination. Imagination will run wild. Today all that is left in the name of religion is stories, stories and more stories. Now you don't know which is imagination and which is the reality. Yes? Many stories, story inside a story, and you don't know where the beginning is and where the end is.
(Excerpt from Sadhguru`s talk)