Does science prove that the self does not exist, and if so what would that mean for human society?

It is difficult to answer a question where the main concept is not well-defined: The Self.

1. Thomas Metzinger, in particular, is one who makes in his book Being No One a precise proposal how to understand the Self-model as part of the world-model of a person.

2. Generally one identifies the Self with the sum of all experiences during their life which a person stores in his memory, the experiences together with their assessment. Also all predeterminations and inheritance from the biological evolution are the frame for the development of the Self.

   These factors can be investigated by science, see Kevin Mitchell Free Agents.

3. Until now, no science proved that the Self does not exist. On the contrary, neuroscience aims at a working definition of the Self. And then sets up to investigate the neuronal correlate of the Self.

You ask:

Does science prove that the self does not exist, and if so what would that mean for human society?

The short answer is no: science does not prove the self does not exist; but it may assume it, if the scientist is so inclined, though the notion there is no self (IEP), it would be an uncommon presumption among scientists of any sort. The belief that the self exists is a natural extension of naive realism, the "default" metaphysics of pre-theoretic thinking. For instance, psychologists tend to presume that the self exists, especially since behaviorism (IEP) fell out of favor, but radical behaviorism, for instance, might be seen as holding that no self exists, at least from a current psychological perspective. Here, B.F. Skinner argued against the use of language regarding mental states in psychological discourse choosing instead to see only the external behaviors of the human being. So, is it fair to say that Skinner argued the self does not exist? Perhaps.

It might be fairer to argue that Skinner's work shows that if the self exists, it exists, not as some sort of essence or substance, but as a recognition that the label 'self' is externally observable sets of dispositions or a collection of behaviors, a history of its function. This would certainly align with some sort of nominalist thinking suggesting that there is no physical self, but is a term simply used by one human to categorize another. But, then, what is the self if it is not the subjective life of a human replete with phenomenological experience including categories and language?

But rather than settle the question, it's important to understand that in a naturalized epistemology, science and philosophy are continuous in a way that the metaphysics of a science are part of its presumptions. In other words, if one were a psychologist, an expert in the mind, one's beliefs about philosophy of mind and psychology primarily inform one's scientific beliefs. That is because science plays the role of a narrow epistemologist helping the thinker constrain metaphysical reasoning with methodological naturalism.

So, science doesn't prove one's first principles, though it may influence selecting them, but rather one's first principles (does the self exist?) tend to become the presumptions of one's science. In this way, practicing scientists, who often themselves have unexamined philosophical beliefs and values, tend to use their intuition to decide which categories are appropriate. Thus, while the claim that the self doesn't exist can be argued, it is an unnatural approach to thinking about the world particularly given how ego both our daily lives and the practice of science itself is.

The key fallacy of your friend is in this sentence:

The ‘self’ is a concept we impose, while in reality, it’s a product of collective responses and emergent behavior.

Even if the world were provably reductionistic deterministic (i.e. all things are reducible to deterministic motions of fundamental particles), this does not mean that the 'self' is imposed by us. And science has not proven that, nor can it ever do so theoretically; we cannot prove that all things that we haven't observed follow the rules of the things that we have observed. Science commonly makes such inferences, and it works pretty well. The question of why is pretty interesting philosophy but beyond the scope of this Q.

For instance, Gottfried Leibniz developed an idea he called "The System of Pre-Established Harmony", in which all the world behaves in deterministic fashion according to physical rules, but it was made in parallel to the human soul in such a way that the behavior of the soul/self runs in perfect harmony with the physical world. So basically the "self" is part of the initial cause of the material world that leads to all the things you experience. While this requires causality to not follow a definite temporal sequence, it is a possibility that allows for both a strong physical reductionism and a real immaterial human soul. (Whether or not Leibniz is correct is of course a different question, but it means that your friend must do some more work to draw the inference which he claims is "proven".)

Science doesn’t prove that the self doesn’t exist; it challenges the idea of a fixed, permanent, independent self. Neuroscience and philosophy suggest the self is a dynamic process rather than a solid entity. This doesn’t erase responsibility or social identity—it invites us to rethink them as evolving constructs shaped by brain activity, culture, and experience.

The material you have quoted is a set of unsupported statements without proper context, and relies on "exists" being poorly specified. It is a misrepresentation of what science says, at best.

By those arguments, nothing in your daily experience of the physical world exists because they are all built of smaller components. As you point out, you exist. The fact the self may also be assembled from components does not mean it does not exist.

Also, we normally do not restrict the term "exists" to physical substances. Ideas, for example, exist though their reference may not; the idea of a dragon exists, for example.

What neuroscience would say is that the self is built from our innate capabilities, our learned capabilities, and a model of ourselves that operates in much the same way that our models of others do. This exists just as much as the combination of a computer's hardware and firmware, data, and running programs do. The fact that some of it is patterns of energy sustained by feedback loops does not mean it does not exist, it just means it is not entirely built out of matter, though it is entirely supported by matter.

There are philosophers who challenge this, asserting for various reasons that the self must be a separate non-physical thing that merely interacts with the physical brain and body. See past discussion here of physicalism versus non-physicalism for extended discussion of that set of beliefs. But even they would say that the self exists, it just doesn't exist where science has yet found a way to examine it. See also past discussion tagged "self".

So, yes, your friend is... confused. Or trying to be confusing. Neither would be especially surprising, both are wrong.

When somebody says it's all an illusion, that's all an illusion.

In my opinion, science does not prove that the self does not exist—it just shows that the self is not a single, solid “thing” in the way common sense imagines it.

Neuroscience suggests that what we call the self is an ongoing process: patterns of memory, perception, emotion, and decision-making distributed across the brain. There is no central “control room,” but that doesn’t mean there is no self—only that it’s dynamic, constructed, and constantly updated. Saying the self doesn’t exist is a bit like saying a wave doesn’t exist because it’s made of moving water.

For human society, this view is more clarifying than destructive. It encourages humility, empathy, and flexibility: if selves are shaped by biology, environment, and history, then moral responsibility still matters, but so does understanding context. Laws, ethics, and relationships don’t collapse—they just shift focus from a rigid, isolated ego to a more relational and evolving human identity.

So rather than erasing the self, science reframes it. And honestly, that version of the self is more interesting—and more humane—than the old, immovable one.

Science deals with physical facts (facts that are perceived empirically, by the physical senses) that can be observed and measured objectively.

Science does not deal with metaphysical facts (facts that emerge rationally, by means of reason) which can't be measured objectively, but are essentially subjective.

The self is a metaphysical entity. It is not addressed by science, but by philosophy.