Most people think that aging is irreversible and we know that there are mechanisms even in the human machinery that allow for the reversal of aging, through correction of diet, through anti-oxidants, through removal of toxins from the body, through exercise, through yoga and breathing techniques, and through meditation.
— Deepak Chopra

The irreversibility of time is the mechanism that brings order out of chaos.
Ilya Prigogine irreversible quote

It is hard to have patience with people who say There is no death or Death doesn't matter. There is death. And whatever is matters. And whatever happens has consequences, and it and they are irrevocable and irreversible. You might as well say that birth doesn't matter.
— C. S. Lewis

In contrast to revenge, which is the natural, automatic reaction to transgression and which, because of the irreversibility of the action process can be expected and even calculated, the act of forgiving can never be predicted; it is the only reaction that acts in an unexpected way and thus retains, though being a reaction, something of the original character of action.
— Hannah Arendt

I believe we are on an irreversible trend toward more freedom and democracy -- but that could change.
— irreversible quotation by Dan Quayle