Vacchagotta, a wandering mendicant, visited the Buddha and asked him if there was such a thing as “self.” The Buddha didn’t answer him but just sat silently. Vacchagotta then asked if there was “no self.” The Buddha was again silent, and Vacchagotta left with his curiosity unsatisfied. Ananda, the Buddha’s personal attendant, was puzzled by the Buddha’s silence and asked him to explain. The Buddha replied:
“Ananda, if I… were to answer that there is a self, that would be conforming with those priests and contemplatives who are exponents of eternalism. If I … were to answer that there is no self, that would be conforming with those priests and contemplatives who are exponents of annihilationism. If I … were to answer that there is a self, would that be in keeping with the arising of knowledge that all phenomena are not-self?”
“And if I… were to answer that there is no self, the bewildered Vacchagotta would become even more bewildered: ‘Does the self I used to have now not exist?'” — Ananda Sutta 
Anatta, or “not-self”, is a frequently misunderstood Buddhist concept. Let’s clear up three common misconceptions about it right off the bat. Buddhism doesn’t deny you exist, deny you have a personality, or imply you shouldn’t have an “ego.” What Buddhism does deny is a false conception of the self: a self that is separate-unto-itself and unchanging.
In its narrowest sense, anatta is a denial of the Vedic conception of atman, an unchanging soul which transmigrates and which, according to the ancient Vedic formula, shares an identity with Brahman, or the godhead. More broadly, anatta is descriptive of all conditioned phenomena, not just the self, and corresponds to the Mahayana idea of śunyata or emptiness: nothing possesses an unchanging self-nature.
The self can be compared to a whirlpool in the ocean. A whirlpool is a distinctive feature of the ocean: it’s visible, tangible, and measurable. It’s real. It exists. On the other hand, at any given moment the water that makes up the whirlpool is different from the water that comprised it a moment before, and from the water that will comprise it a moment later. The whirlpool is a pattern that retains a discernible identity while it continues to exist. At any given time, there is no separation between the whirlpool and the ocean. It makes no sense to say that the whirlpool is “here” and the ocean is “there.” Whirlpooling is a feature of the ocean.
It’s the same with the self. The self exists as a pattern: a pattern of behavioral response. But that pattern is always in some degree of flux. While I am always, in some sense, the same person, I am different now than I was at age three, and different from the way I will be at age eighty. My intellectual capacity and memory will decline as I age. My tastes and opinions may change as well. While we are a relatively enduring pattern, we are also constantly changing: learning, developing, maturing, declining. We also change depending on the situation we find ourselves in. We behave differently at work, at home, in the bar, and in the zendo.
We are also inseparable from the world around us. Our skin connects us to the world, rather than separating us from it. It excretes, transpires, absorbs. We are constantly taking in the environment as we breathe, drink, eat, listen, watch, and feel. We are constantly returning parts of ourselves to the environment as we sweat, excrete, exhale, and communicate. Our body is constantly shifting state in response to the environment: its temperature, brightness, noisiness, novelty, and complexity. Our minds are also inseparable from the world. They are made up of memes  and schemas  learned from parents, teachers, peers, opinion makers, and the media, and through our interaction with the world. We are like the whirlpool and the ocean: there is no place where we stop and the world begins. This is our self: changing and interconnected.
Synchronic and Diachronic Self Obervation
In meditation we observe the present moment. This is what can be called synchronic observation, as opposed to diachronic observation where we study phenomena over time. In any given moment or succession of moments we can observe a flux of sensations, sounds, smells, thoughts, images, memories, but no self. Meditation reveals a world of sense objects and a process of knowing, but nothing solid we can call a self. The Scottish empiricist philosopher, David Hume (1711-1776), came to the same conclusion as the Buddhist meditators about this:
“For my part, when I enter most intimately into what I call myself, I always stumble on some particular perception or other, of heat or cold, light or shade, love or hatred, pain or pleasure. I never can catch myself at any time without a perception, and never can observe any thing but the perception…. I may venture to affirm of the rest of mankind, that they are nothing but a bundle or collection of different perceptions, which succeed each other with an inconceivable rapidity, and are in a perpetual flux and movement.”
When we observe human behavior (including mental behavior) over longer periods of time, however, a different picture emerges. We can observe regularities in thought and behavior that recur over time and across situations that are typical for a given individual, at least over a circumscribed time period of months and years. These regularities are what we mean when we talk about personality, character, and the nature of self. 
Jeffrey Rubin discussed the difference between synchronic and diachronic views of the self in “Close Encounters of a New Kind: Toward an Integration of Psychoanalysis and Buddhism.  Rubin compared synchronic observation to looking through a microscope, and diachronic observation to looking through a telescope. He argued that neither method provided what he called “immaculate perception:”
“The self (or anti/no-self) that they “discover” is intimately related to how they investigate it. The telescopic approach to self-experience employed by many psychoanalysts yields a substantial self shaped by a particular history. Examining self-experience microscopically as Buddhist meditation does, reveals the fluid and unfolding nature of identity, the way we are shaped anew, moment-by-moment. We need a bifocal conception of self that realizes that the self is both a substantial, embodied, historical, agent as psychoanalysis suggests, that perceives, chooses, and acts, and a fluid, uncongealed process that is created afresh by changing states of consciousness in the present. Each conception of self is useful in particular circumstances.”
Why is any of this important? Thanissaro Bikkhu has argued that the Buddha’s intention in discussing anatta was not to make an ontological or metaphysical point about the existence of the self, but to make a soteriological point about how to relieve suffering. How then does a belief in a skin-encapsulated, isolated, unchanging self lead to suffering? Here’s one answer from a (slightly altered) book chapter  I wrote a few years back:
“There are real existential and ethical consequences that flow from our erroneous view of selfhood. On an existential level, the existence of this inner self separates us from the rest of creation; we believe we are different from stars, rocks, ferrets and daisies; we believe ourselves to be this free mental thing that stands outside of materiality and causality. When we experience ourselves as a process that is one with the universe, however, our sense of existential loneliness and estrangement drops away. Our sense of existential estrangement underlies some of our most destructive behavior. When we harm the environment or another being we feel we are harming something other than ourselves. When we wake up to our existential continuity with Being, we realize that when we harm others we are harming ourselves….
We are always worrying about the status of this self as if it was a currency whose value was floating in a free market: “What’s the value of my self at this moment?” In contemporary free-market societies the self seems to fluctuate in value from moment to moment. The resulting insecurity means we are always trying to enhance our value through the accumulation of wealth, power, and status, through the pursuit of perfection, through ceaseless defensiveness and self-promotion, and through the defeat and humiliation of our rivals. The anxious self, worried about its own insufficiency, is at the root of most human cruelty….
There are also psychological consequences to our erroneous view of the self. Our clinging to a separate, enduring self can become a false refuge from existential anxiety and can impede a genuine awakening to our human condition. We often hear exhortations from within the self-help community to “express ourselves,” “love ourselves,” “be our true selves,” and “discover ourselves.” These exhortations have genuine value when they encourage the undoing of habitual self-abnegation, self-hatred, or self-obliviousness. They become hindrances, however, when they encourage glorification of the self, or pursuit of the self as an end-goal in life… The Buddha believed that trying to take refuge in insubstantial, transient, and ultimately unsatisfying things was the root cause of human suffering. The belief that “if only I had this I would be happy” is reborn in the human heart in each and every moment: “If only one had more money”, or “a better job,” or “a better partner,” or was “more beautiful,” or “talented,” or “healthier,” and so on, ad infinitum. This belief in psychological rescue and refuge in ultimately unsatisfying things leads us to waste our lives in their pursuit, or leads us to berate and hate ourselves for failing to obtain or be them.
The Buddha believed that if one clearly saw that the self for what it was, one would not cling to self, and that this would assist one in ending suffering… One would not take pride, for example, in being intelligent, and use that personal characteristic as a way of feeling either existentially sufficient or superior to others. Intelligence is not a static, fixed thing: we act intelligently one moment and stupidly the next. Intelligence is not permanent: at any moment it can be impaired by age, injury, or disease. Intelligence is also not “ours;” we cannot take credit for it: It is a function of our parents’ genes, adequate nutrition, gifted teachers, the inculcation of good study habits, and the knowledge passed on to us from past generations. So there is no reason to cling to it: it is something that is here due to previous causes and conditions and is ephemeral. It is the same with every trait that we take to be part of the self: our kindness, our beauty, our courage, our strength. All of it is due to causes and conditions, and will vanish with changing causes and conditions; none of it is ours. We can be happy it is here, but it can’t be our refuge.
Not that the self is all bad. All human beings above a minimal level of intelligence develop a sense of self, regardless of culture. It’s also clear that they do so at a very early age, although the sense of self continues to elaborate and develop across the life span. The universality of the self suggests that we are biologically predisposed to develop one, and that this self must have important survival value for us as a species. This sense of self and agency are also deeply imbedded within language which has a semantic structure based on the distinctions between actor, action and object. While some think that our sense of self grows out of the semantic structure of language, it seems more likely that a proto-self emerges prior to language acquisition, and that both the self and the semantic structure of language have similar roots in the structure of human experience given our biological makeup and our interaction with the world.
Some of the earliest roots of the self lie in mammalian behaviors such as territoriality, possession, and the social structure of the pack. It’s easy to intuit the survival values of those behaviors and their role in natural selection. It is also easy to tie identity formation to the welfare of the family and clan; identity is in part determined by the reflected appraisals and ascribed roles of family and clan, and in turn serves as a locus of social responsibility for parents and teachers as they enculturate the child.
The fact that we are biologically predisposed to view things in a certain way, and that it might be useful to do so for some purposes, doesn’t mean that it is the only, or even the most useful, way to view things. We are biologically predisposed to see objects as solid, and it is in many ways useful to do so; but objects are mostly empty space, and viewing them as solid prevents us from making other kinds of use of the material world. It looks to us as if the Earth is flat and that the sun moves around it; for most purposes that suits us well, but it is woefully inadequate for other purposes. As our social and intellectual evolution progresses, and as our species continues to interlink across the globe and reach beyond it, and as we begin to alter our environment and genetic makeup in radical ways, and as we develop technologies that can lead to our own extinction, prior ways of seeing things may no longer serve us. In our ancestral world of open space and small competing clans with only limited powers of control and destruction, the old view of self and other may have been good enough. Now, perhaps, a view of understanding what connects us, the unity of all things, a vision of inter-being, becomes imperative if we are to survive as a species.
One further problem with a false view of self is that it can prevent us from growing psychologically and spiritually. We can mistakenly believe that our narratives about ourselves are our true indentity, and not see them for what they are: just stories. Often we can be hemmed in by inadequate narratives that preclude and hamper our ability to change. If one sees onself as inferior, or deficient, or “an addict,” or a “mental patient,” or “a victim,” for example, one may buy into that definition. If you are woefully deficient in some way, there is nothing you can do about it. You just have to suck it up. Personal growth requires us to let go of old stories and definitions and try on new identities. The less intensely one clings to a particular identity, the greater the potential for growth and change.
The Buddha, in neither endorsing self nor not-self in response to Vacchagotta’s questions, came awfully close to the four-fold denials of Nagarjuna, the second century poet-yogi-philosopher. We can always count on Nagarjuna to take things one step further, so it’s fitting to end this post with Nagarjuna’s take on self and not-self:
“It is said that “there is a self,” but “non-self” too is taught. The buddhas also teach there is nothing which is “neither self nor non-self….” Everything is real, not real; both real and not real; neither not real nor real: this is the teaching of the Buddha.” –Nagarjuna, Mulamadhyamikakarika (Stephen Batchelor trans.)
Everybody got it?