If there is no self, why do anything?

SIMPLE ANSWER: we do not have a self but neither do we have a not-self. Hence self-realization is still vital as we are statistically in the rarity in this existence! This life's opportunity is still yours to lose/win!

If there truly is no self, surely we would all just freeze motionless, die and return to nothingness.

This point of view that it is all nothingness is verified by science and Buddhism. There isn't really anything that signifies some grand centric-ness. Some electrons here and there randomly shaping itself into temporary concreteness.. Yet... Everything objectively is nothingness from a zoomed out point of view...

Heart sutra explains this and says "gate gate paragate parasamgate bodhi svaha!"

Originally everything was still. And then there was a tiny bit of Ignorance and from this first bit arose some sort of contrivance, creating stuff, and then consciousness, name-form, sense, contact, feeling, craving, and all the rest in turn that each being is now trapped in. https://en.wikipedia.org/wiki/Twelve_Nid%C4%81nas

Nonetheless, it doesn't mean that "nothing matters." It certainly matters because one is now stuck in some sort of loop, ruled by loops of desires, karma and birth-and-death--no longer limitless potential. This illusion is very much real. Just like how the illusion of a computer screen, bits and digits being converted to pixels appearing as letters before you and thus this writing actually MEAN something... now that we are in this, it DOES mean something. Now you are stuck in an endless route of contrivance even if you try to do nothing! Thus, the question in Buddhism is how to return to Oneness. That is a scary thing for most people though since we are so used to self (eons of this illusion of self with countless rebirths). Thus the journey of Buddhism and the myriad meditation practices all of which are like medicine and the journey which Buddha somehow after countless lifetimes managed to figure out (loads of trial and error).

Lastly, "why do anything", because you temporary form will have to die and the temporary, changing consciousness that you are will move from body to body, and no matter where you go in the ginormous universe, the karma will be spent up and you will end up going to lower realms (imagine being chopped up as a pig or burning in hell) unless you at least attain initial enlightenment.

Then at least you will be safe from endless suffering, never to fall back into complete ignorance again... and most importantly spiritually you can help other beings due to superpower and eventually fold back into the fabric of the universe into Complete Enlightenment and really become nothing. But only when you want to/can.

This is an important question that has been provided with many confusing answers. In the Theravadin tradition, the Buddha considered the concept of self, in its many variations, to be a source of confusion among his students. In particular, he was concerned when a student viewed the self as an important object of meditation, as when a person viewed discovering the “true” or “real” self as a source of wisdom or liberation. (This concern is not that of the Mahayana tradition.) In essence, the Buddha argued that the notion of self is generated by the process of sankhara and therefore a matter of how we make sense of a collection of perceptions, feelings, desires, and beliefs we experience in relation to ourselves. By explaining how the process of sankhara generated the concept of self, he demonstrated that there was no “true” or “real” self to be found. Sankhara is an unconscious mental process that makes sense of we perceive and experience and provides action-plans that make sense to us. Sankhara is a complex and sophisticated unconscious mental process that makes survival and intelligence possible. (It is important to observe that, in the Theravadin tradition, the Buddha was not concerned about the use of “I,” “me,” or “you” in language, which another topic that is of concern in the Mahayana tradition.) Although we experience our minds and bodies in a multitude of ways, he argued, none of these experiences provide evidence of the existence of an uncaused entity that could be called “The Self.” It may be noticed that this argument is entirely within the realm of relative truth and makes no reference to the concepts of sunyata or absolute truth and must therefore be distinguished from the very different arguments provided by Mahayana Buddhism. The Mahayana arguments are also true but for very different reasons.

To accept the no-self (anatha) reality as a Buddhist doctrine is only the soil around the redwood seed on its elaborate path to become the reality of an unshakable established truth. It provides an opening towards the vast and often difficult work to fully understand the impermanence of all phenomena. There is a lot to do Tamatama.

Given that the mind is filled with conceptual illusions that are often out of touch with the reality, your perception of self is the same. You visualise it as a box of candy, for example; it has higher logical skills, good driving skills, it is socially anxious, doesn't like spiders, thinks of itself as a calm person.

See, the problem with that image is that with any discrepancy that will occur to any of these, we will have a negative feeling towards ourselves because it doesn't match the blueprint. And then, out of self hatred that we fail to adhere to this imaginary vision of ourselves, we will attempt to self improve. It is a never ending chase that only brings grief. We become obsessive thoughts, we become emotions, and then we stop being them as they dissolve. I was a different person yesterday as weather affected my mood.

It is best to avoid such vision and believe in interconnectivity of all things that constitute the wholeness of reality. Creating these isolated islands of "Selves" make us think in a very inward, depressive fashion. We become self centric and don't open to the world. But space is an illusion! Our mind just fails to see that everything is filled with particles and therefore connected into one reality. Whatever I do, I don't do in the sandbox, I interfere with the whole universe at once. Hence cause and effect brings pain and suffering, but it might also bring joy if utilised in a selfless fashion.

We should flow like water - form, shape and a label shouldn't matter at all, they are just concepts of the mind. It is a liberating experience.

The delusion of if there is no self, then there is no point to do anything is mainly due to that you are currently having the intellectual view of there is no self. Whereas deep down, you still believe in a self. When there is that self view, kamma still works very well. Thus your actions have consequences.

In terms of 5 aggregates way to see things, the 4 aggregates of form, consciousness, feelings, perception are the receiver of the results of kamma, but the mental factors lead by volition is the creator of kamma. Together the 5 aggregates which we commonly think of as a self is actually not worth calling a self due to them being impermanent, thus subject to suffering. Regardless, as long as the realization that there is no self had not been attained, kamma still works to its full extend. Once stream winner is attained, the kamma to go to lower realms become defunct. Once arahanthood had been attained, one can no longer produce kamma. Results of past kamma can still happen until the final death, but kamma with regards to all future lives becomes defunct.

So actions still plays a very important role as it can even affect the results which happens to you even if you attain to arahanthood. Of course, after you attained to arahanthood, you don't think in any sense "I attained to arahanthood" as the concept of self becomes totally known as a delusion, a story.

So to return to the details of your question, people who are not enlightened, do stuffs having the delusion of self, thus the motivation can be driven by greed, hatred, delusion, or non greed, non hatred, non delusion. Take note that a delusion of self is needed to drive greed, hatred, delusion. If there is a self, I want it to be happy, so I go after things which makes it happy (greed) and avoid things which makes it unhappy (hatred).

Arahants are not immobile people do does nothing even after realizing nonself fully. They can be motivated to do stuffs by generosity, loving-kindness, compassion, wisdom, etc. It's also pure altruism as there is no concept that the results of these good deeds will come back to the arahant, as indeed an arahant cannot produce kamma, so any good deeds he does, does not brings results (back to him). And he is incapable of unwholesome deeds as the roots for them are totally eradicated.

I guess a simplistic (or "simplest possible") answer might be that we do things out of ignorance, greed, and (maybe) aversion too.

And maybe other motives are identified, in the Opposite wholesome qualities:

The three wholesome mental factors that are identified as the opposites of the three poisons are:

• amoha (non-delusion) or prajna (wisdom)
• alobha (non-attachment) or dāna (generosity)
• adveṣa (non-hatred) or mettā (loving-kindness)

Also I'm not sure about your premise, that "there is no I" or even than there might be no I.

So far as I understand it, questions about whether the self exists or doesn't exist, will exist, won't exist, used to exist, and so on, lead to a "thicket of views" and not to liberation:

This is how he attends inappropriately: 'Was I in the past? Was I not in the past? What was I in the past? How was I in the past? Having been what, what was I in the past? Shall I be in the future? Shall I not be in the future? What shall I be in the future? How shall I be in the future? Having been what, what shall I be in the future?' Or else he is inwardly perplexed about the immediate present: 'Am I? Am I not? What am I? How am I? Where has this being come from? Where is it bound?'

"As he attends inappropriately in this way, one of six kinds of view arises in him: The view I have a self arises in him as true & established, or the view I have no self... or the view It is precisely by means of self that I perceive self... or the view It is precisely by means of self that I perceive not-self... or the view It is precisely by means of not-self that I perceive self arises in him as true & established, or else he has a view like this: This very self of mine — the knower that is sensitive here & there to the ripening of good & bad actions — is the self of mine that is constant, everlasting, eternal, not subject to change, and will stay just as it is for eternity. This is called a thicket of views, a wilderness of views, a contortion of views, a writhing of views, a fetter of views. Bound by a fetter of views, the uninstructed run-of-the-mill person is not freed from birth, aging, & death, from sorrow, lamentation, pain, distress, & despair. He is not freed, I tell you, from suffering & stress.

Also, any view-of-self leads to suffering (see this answer for details and references) ... and I think that "view of self" includes "I exist" and "I don't exist": these would both be considered self-views.

Experiances come into being by causes and so does a notion of "I" or "self" (one of the governing princibles). It's wrong to think that the way to liberation is primaly done by placing the strategy of not-self to it. A good and healthy self-esteem is a fundamental reqirement, and since nothing is more dear to being than one self, it's actually the drive to liberation.

Some very good explainings how to apply certain self and not-self strategies for going beyond all kind of self-views is certainly given in the teachings of: Selves & Not-self: The Buddhist Teaching on Anatta

Experiment with it and find out by yourself, using the basics, generosity and virtue as guides while walking toward concentation and seeing as it is.

And yes...

Doing the Math

The Dhamma is like doing math. There's multiplication, division, addition, and subtraction. If we can think in this way, we'll be intelligent. We know the right time and place for things. We subtract when we should subtract, multiply when we should multiply, divide when we should divide, add together when we should add together. If we multiply every time, our hearts will die from the burden. In other words, we have no sense of enough. No sense of enough means no sense that we're growing old.

Anyone with a sense of growing old is a person with a sense of enough. When there's enough, the words, "Okay, that's plenty," can make their way up. If there's not enough, that "okay" can't make its way up because we keep on wanting to take. We've never thrown anything away, let anything go, put anything down. We're always taking. If we can "okay," we're at ease. That's enough.

[Note: This is a gift of Dhamma and not meant for commercial purpose or other low wordily gains by means of trade and exchange.]

When not-self is fully realised there isn't anything to do; apart from to help others realise not-self. That is why the suttas say about the fully enlightened state of mind: "There is nothing further in this world". Because the full realisation of not-self is the supreme liberation or happiness, the fully enlightened person only performs compassionate actions to help others realise not-self.

No matter if we do or do not have a self

The view that we "surely have a self or soul",

drives our desire to propel through life.

We want to be & to do & to exist.

So the goal of the practice is to:

• let go of the desire to be anything.
• let go of the desire to do anything.
• let go of the desire not to be anything.
• let go of the desire not to do anything.

It is not that you existed and then you ceased to be after learning Buddhism. You never existed. You did no action. Your identity of self was an illusion. If you did not do any anything in the past then will you do anything in the future ? No. If you did not do anything in the past then will you do anything in the present ? No.

Give up the identity of Self. Give up the desire to be Mr. Somebody. None of the identities are worth identifying as Self.

It is not that there is no self. There is no self in the way you think of a self. That is, there in nothing inherent in what you refer to as "I".

When you understand this, you free yourself and your actions are able to transcend limits. With this understanding, your actions become perfections.

Which is why everything you do should be with an understanding of selflessness.

It essentially doesn't change anything. If you look hard, that "I" was always an illusion. No matter where you try to draw a boundary - it is artificial:

• Does the body belong to the self or not? How about that constant flow of matter and energy in and out - at what point does it even belong to the body?
• Do thoughts belong to the self or not? You are hopefully aware how much of your thoughts are triggered by others, or even just repeat outside influences. Often they are even rationalizations of what you just did for other reasons.
• Do feelings belong to the self or not? Much of these are determined by past experiences, your situation, even medications, weather, food.

So, to keep up this delusion of an "I" separate from the rest of the world requires carefully ignoring all things saying otherwise, which is stressful, even harmful to keep up. If you let that drop away, you'll function as you always did, but with loads of more peace. Don't worry - if this body is hungry it will eat, no matter whether you create such mental complications around that process - or not.