Excerpts from books, lectures, and videos by Jagad Guru Chris Butler (Siddhaswarupananda Paramahamsa).

Let me ask you a few simple questions:

Do you exist at this moment?
Did you exist five years ago?
Are you your body?

Most people would answer “yes” to all three questions. But if you identify your body as yourself, and simultaneously accept that you exist now and also existed five years ago, then you have a problem: The body you had five years ago does not exist today. There is a dynamic turnover of atoms and molecules that make up your body. There isn’t a single particle of matter—not one atom—present in your body today that was present five years ago.

The body you have today is not the same body you had five years ago. It’s not that the body you had still exists but has now changed somewhat. No. The body you had is completely gone. That collection of atoms appearing as flesh, bone, blood, hair, and so on no longer exists. Yet you still exist.

Studies at the Oak Ridge Atomic Research Center revealed that about 98 percent of all the atoms in a human body are replaced every year. You get a new suit of skin every month and a new liver every six weeks. The lining of your stomach lasts only five days before it’s replaced. Even your bones are not the solid, stable structures you might have thought them to be: They are undergoing constant change. The bones you have today are different from the bones you had a year ago.

Experts in this area of research have concluded that there is a complete, 100 percent turnover of atoms in the body at least every five years. In other words, not one single atom present in your body today was there five years ago.

If you were the molecules and atoms of which your body used to be composed, you would now be a personality divided into the many new bodies that those atoms and molecules have become part of.

And, of course, the molecules and atoms that make up your present body are not “new.” They too are used. Your body is made of recycled material. The matter you now call “yourself” was once part of many different collections of atoms and molecules that went by different names.

This way of looking at the situation reveals the absurdity of Sagan’s conclusion. If the body is the self—if you are a collection of molecules and atoms—then when those particles disperse, that’s the end of that particular “collection.” That collection of atoms and molecules that went by a particular, distinct, collective label (your name) no longer exists.

If you are the body, then when the body is gone you should also be gone. But this isn’t the case.

So when you look at a picture of “yourself” taken only seven years ago, you are looking at a body that no longer exists. Every single molecule that was present in the body shown in the photography is now gone. Yet you still exist. You are not gone. Now, since the body you had seven years ago no longer exists, yet you still exist, you must logically conclude that (1) you were not the body you had on seven years ago, and (2) you are not the body you have on today.

The material body has sometimes been compared to clothing worn by the self. At one point you had a baby body; then you took off the baby body and put on a child body; later on, you wore an adolescent body; and after that, you put on a young adult body. In all cases it was you, the same self, who was wearing those different bodies.

You—the self—are the constant factor in the sea of physical/bodily material changes.

You know that you existed seven years ago; you were there. You also know you exist right now. The same you, or self, who existed then also exists now. And this same self will exist when the present body is gone.