Consciousness, death and reincarnation

Question

First of all, I'd like to say I'm a scientist. This means fact will always come before faith, even if it hurts. In general, one's opinion doesn't mean much if the question itself has no meaning, but when the question is well phrased and has a quantitative background, then experiment is the ultimate - and decisive - destination.

Secondly, I'm afraid this will be a rather long question.

According to Walpola Rahula in his book What the Buddha Taught, Buddhism denies the existence of a soul or spirit:

Buddhism stands unique in the history of human thought in denying the existence of such a Soul, Self, or Atman. According to the teaching of the Buddha, the idea of self is an imaginary, false belief which has no corresponding reality, and it produces harmful thoughts of 'me' and 'mine', selfish desire, craving, attachment, hatred, ill-will, conceit, pride, egoism, and other defilements, impurities and problems. It is the source of all the troubles in the world from personal conflicts to wars between nations. In short, to this false view can be traced all the evil in the world.

This pleases me very much. As a scientist, I cannot conceive the existence of something we cannot observe or measure that lives on after I die. Everything Buddhism talks about pleases me very much: everything is dukkha, there's a way out of dukkha, we are unhappy because we cling to everything, and the path outside this unhappiness is to understand nothing has intrinsic value or meaning. In resume: I think Buddhism, unlike the other religions I've been exposed to, is beautiful and makes sense. But then I have a problem - and it's a big one, because it's in the eye of the tornado.

According to Walpola Rahula (same book),

Will, volition, desire, thirst to exist, to continue, to become more and more, is a tremendous force that moves whole lives, whole existences, that even moves the whole world. This is the greatest force, the greatest energy in the world. According to Buddhism, this force does not stop with the non-functioning of the body, which is death; but it continues manifesting itself in another form, producing re-existence which is called rebirth.

Now we have a problem. I've seen people discussing the differences between mind, brain, consciousness, etc. Well, science is pretty clear: the evidence is now overwhelming that every aspect of the mind is produced by the brain. I'm pretty familiar with NMR scanning and did read some hundreds of articles about the subject, and we have a huge, massive consensus that nothing survives our death. Not a force, not a will... Nothing. We can't see nothing. It doesn't exist.

Now, I have come to a more traditional (non-westernized) version of rebirth by reading this wonderful, majestically written article by an evolutionary biologist (and aspiring Buddhist): even though people like to talk about rebirth as a deterministic process, it is not. It appears Buddha himself (see article) has said that rebirth is like lighting a candle with another's fire: everything is lost and there cannot be a causal process that links you to "former lives". Actually, the only part of rebirth that doesn't violate scientific laws is to say that my atoms will be reborn in other creatures and objects. And that pleases me very much.

Now, a famous quote says that:

If science proves some belief of Buddhism is wrong, then Buddhism will have to change.

It is attributed to Dalai Lama (probably wrongly), and is found in this great article by Tenzin Gyatso, where many scientifically proved benefits of meditation are discussed. If this sentence makes sense to Buddhists, why do they keep insisting in the concept of rebirth? Science is clear: there's no support of any evidence in its favour, at least not in the way I see people treating the subject. Buddha's metaphor about "lighting candles" is much better to have as an example, since it doesn't contradict facts, even though it doesn't make a lot of sense either.

I'd therefore like to know passages from suttas where Buddha affirms that knowledge of past lives is unattainable, or at least where He elucidates reincarnation is not something causal. If there aren't any, why do people still believing in this concept? Only because they feel safer?

Edit: This question is turning into a chimaera of weird unwanted lessons: people telling me I'm not ready for knowledge, or that articles that elucidate their misconceptions are not valid, or that I don't know the meaning of truth, or people trying to teach me concepts my PhD is about, and even people saying their own views are perfect. Until now, the most useful references where given by Dhammadhatu, and the best answers by ChrisW and Tenzin Dorje. Please refrain from counselling and preaching.

Answer 1

why do people still believing in this concept? Only because they feel safer?

That sounds like a question which ought to have been answered by this earlier question: What's the value or harm of a literal belief in rebirth?

The most on-topic answer to that question seems to me to be Ven. Yuttadhammo's, and the second article of Bhikkhu Bodhi's which he quotes.

I summarize these answers as:

• It's what the Buddha taught, according to the suttas
• It encourages moral behaviour (even virtuous deaths)
• It encourages us to be, not only heedful of the now, but to also wisely review our past
• It makes us examine cause-and-effect, and conditionality (as you are doing, in this topic)
• It makes us consider what (and when) conciousness is (e.g. it's not the same thing as the body)

I'd therefore like to know passages from suttas where Buddha affirms that knowledge of past lives is unattainable, or at least where He elucidates reincarnation is not something causal.

There are passages in the suttas where, I think, the Buddha affirms that he has seen his own past lives. It's described in Maha-Saccaka Sutta MN 36 in which he describes his becoming enlightened:

When the mind was thus concentrated, purified, bright, unblemished, rid of defilement, pliant, malleable, steady, & attained to imperturbability, I directed it to the knowledge of recollecting my past lives. I recollected my manifold past lives, i.e., one birth, two...five, ten...fifty, a hundred, a thousand, a hundred thousand, many eons of cosmic contraction, many eons of cosmic expansion, many eons of cosmic contraction & expansion: 'There I had such a name, belonged to such a clan, had such an appearance. Such was my food, such my experience of pleasure & pain, such the end of my life. Passing away from that state, I re-arose there. There too I had such a name, belonged to such a clan, had such an appearance. Such was my food, such my experience of pleasure & pain, such the end of my life. Passing away from that state, I re-arose here.' Thus I remembered my manifold past lives in their modes & details.

This was the first knowledge I attained in the first watch of the night. Ignorance was destroyed; knowledge arose; darkness was destroyed; light arose — as happens in one who is heedful, ardent, & resolute. But the pleasant feeling that arose in this way did not invade my mind or remain.

In other suttas the Buddha sometimes also described what someone's current (new) abode was, after they died.

But apart from that, to try to answer your question, there are other suttas too, where I think he does suggest that knowledge of past lives is unattainable or, at least, not a useful goal at this stage.

The Sabbasava Sutta warns that there are questions:

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? etc. etc.

... and views:

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 etc. etc.

... and warns that these kinds of thinking do not lead to freedom:

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.

I take that as a warning that thinking about (having views about) a "self" will produce a "thicket of views".

Another part of Buddhism Dharma is anatta which you may need to integrate or reconcile with the theory-or-doctrine of rebirth.

Some (many) people distinguish "reincarnation" from "rebirth": in that "reincarnation" implies that something, the same thing (e.g. a "soul"), is being reincarnated (which is contrary to the Buddhist doctrine of Anatta); whereas "rebirth" just implies another birth (of a different "being").

And some people say that "past life" is a mistranslation of "past abode" ... and that successive lives should be understand as successive moments of being or of identity-view (i.e. of believing that the self exists), within this (body's) life ... I think this is as opposed to a so-called "literal belief in rebirth".

Actually, the only part of rebirth that doesn't violate scientific laws is to say that my atoms will be reborn in other creatures and objects.

If my mum and I look at some apple, do we see the same thing? Are we both conscious of seeing it? Do we both have apple-seeing-consciousness? Do we share apple-seeing-consciousness? And without "she" and "me" as personal identities, does apple-seeing-consciousness exist in two bodies?

It may be a mistake to see them as "my" atoms (or my apple-seeing-consciousness). The first sutta of the Anatta doctrine teaches, "this is not me, this is not mine, this is not my self".

the evidence is now overwhelming that every aspect of the mind is produced by the brain

Taking Isaac Newton as a famous example, isn't it more obvious that (moment of) consciousness was produced by an apple, falling on his head?

I think I understand what you're saying, though, which is that "mind is conditioned by the brain". I think that translations of Buddhism into English uses the verb condition, to mean, "a brain is a necessary condition for a mind to exist, so if brain ceases then mind ceases (or, mind doesn't arise) too".

But rebirth: a new brain, the whole apparatus (ignoring, for the sake of argument, possibility of rebirth in one of the formless realms).

Answer 2

Everything is dukkha

Not everything is dukkha. Otherwise, there would be no way out.

Nothing has intrinsic value or meaning.

It is not so much that phenomena lack intrinsic value or meaning, it is that they lack intrinsic existence. The object of negation is a mode of existence, it is not just value or meaning.

As to your question, consciousness is that which is clear and knowing. It is in the nature of clarity and has the function of knowing. Since a consciousness is always a consciousness of something, we usually speak in terms of instances. For instance, we speak of "an eye consciousness apprehending a cup", "an ear consciousness apprehending a birdsong", "a memory consciousness remembering a person" and so forth. There is no consciousness that does not depend on a basis that is its apprehended object. This is one of the various reasons we say there is no soul (if by soul we mean something immaterial that does not depend on an apprehended object).

Furthermore, we would probably agree with the scientific claim that "Consciousness depends on the brain." The whole question is: In what way does consciousness depend on the brain? What is the nature of that dependence?

A consciousness also depends on its apprehended object, since there is no independent consciousness. A consciousness also depends on its function, since there is no consciousness that does not accomplish a function. A consciousness also depends on the previous moment of consciousness, and so forth. Thus, a consciousness depends on various factors, but that does not mean that these factors are necessary conditions.

I doubt His Holiness (whom you quote) would be convinced that the brain and consciousness (that is, the mind stream) are one entity. I doubt he would be convinced one is a necessary condition of the other. In fact, there is no proof that the brain is a necessary condition, merely that consciousness depends on it. In short, we do not know the nature of this dependence.

All in all, His Holiness's school posits that the substantial cause of consciousness is a preceding moment of consciousness. It means that a consciousness is like a seed to a tree. A seed causes the tree, it becomes the tree, it no longer exists at the time of the tree (unlike your parents who caused your birth and still exist after that), and is a necessary condition. It is the main reason why we say that, since a consciousness can not turn into anything but a next moment of consciousness, the continuum does not end. So-called Hinayana tenets might hold a different view.

Answer 3

the path outside this unhappiness is to understand nothing has intrinsic value or meaning.

There is intrinsic (objective) meaning to be found. It is the truths of anicca (impermanence) and anatta (non-self).. Relational QM (because it fixes the EPR paradox), the effectiveness of General Relativity, which is background independent (as well as it's global solution of 'nothing happens' which agrees with RQM), Noether's theorem, the observed flatness of (local) space time all point to these two, in one way or another.

The Dhamma is the unalterable law that experience is conditioned, dependently originated, without an intrinsic, Essential Self - without the Form that Plato's Parmenides had so much faith in, even after he demonstrated logically that it made no sense!

Within conditioned experience, there is no thing (I prefer 'no thing' to 'nothing' as the former describes a lack of conceptualization, whilst the latter is a concept about the lack of concepts) to fall back on as intrinsically true. However, that does not mean that experience does not operate on a rule that is omnipresent (not omniscient or omnipotent).

The law of this world, empty of Essence, is one of regularity. Regularity in physical systems, chemical systems, biological systems. https://phys.org/news/2017-03-physics-wealth-inequality.html for a physics theory that seemingly explains wealth inequality in society. The Buddha simply pushed the boundary of this regularity into the field of ethics.

The way I see rebirth (and this is a personal conception, one I believe is at best an inaccurate approximation of rebirth, because there are Essential elements to the thought process), is that in a boundless existence (as anicca and anatta imply), at each instant in time, beings arise, with an average Kammic load of 0 (no Essentials means it cannot be any number other than that at the limit of 'all experience', but then 0 is a pretty essential concept, so bear with me!). However, there will be a myriad of beings ceasing who would have led immoral lives, a myriad of beings ceasing who would have led moral lives, a myriad arising who will begin life with a disadvantage, a myriad who will begin life with an advantage. Net-net, you have two options - you can say that there is no connection, that beings arise in their circumstances by chance, or you can connect all the dots, linearly, as a one-to-one function, from death to rebirth.

"When each individual frame of reference is taken into account, the perception of experience will match experience, on average, as a one to one function". To deny that on average, the perception of violence would have manifested as 'violence', the perception of greed would have manifested as 'greed' (even if those are empty terms in themselves), is to deny the regularity that is so evident within our modern, scientific understanding of the world. External conditions can play a chancery role on the small scale, but there are no external conditions to the 5 skandhas (the mind-body experience as defined by the Buddha), and therefore for rebirth - which is a concept that requires a consideration of All of experience, chance simply has no place.

Science takes the general view (imo) that the physical world is objective, and it leads to, produces a subjective, conscious experience. The Dhamma however, is dependently originated, with neither 'body' nor 'mind' being the causal element for the other - they arise together.

Answer 4

As a scientist, I cannot conceive the existence of something we cannot observe or measure that lives on after I die.

... Well, science is pretty clear: the evidence is now overwhelming that every aspect of the mind is produced by the brain.

Sense impressions are tied to the mental body while conceptual impressions are tied to the physical body. Your mental body process surview death. More on this see this answer and this answer.

deterministic process, it is not

And going further, he reviews bones covered with skin, flesh and blood, and he knows the unbroken stream of consciousness as established in this world and established in the next.

...

And going further, he reviews bones covered with skin, flesh and blood, and he knows the unbroken stream of consciousness as both unestablished in this world and unestablished in the next.

Sampasadanīya Sutta (Quoted from Piya Tan's Translation of DN 28)

The process may initially seem continuous but in reality it is discontinuous. Given your field best is to see it as a discrete stochastic process. Some of the basic causality arisen stream of states is described in Dependent Arising. Also see: Dependent Arising by Piya Tan

The rebirth is also probabilistic. So is Karma in general. Good Karma increases the possibility of good future states. These states arise and pass in much rapidity.

If there aren't any, why do people still believing in this concept?

Abhidhamma studies by Nyanaponika Thera, page 45 describes, momentarily Dependent Arising.

When you get into deep meditation (many years of practice for some) you will see this process. This is not to be believed. It is to be verified at the experiential level. In the training follows this principle:

• theory - to be learned and develop some faith just enough to explore further
• practice - practice which leads to verification of the theory
• verification - observed and verified results

Now rebirth cannot be verified without the practice leading to it. You can verify past lives if you develop the ability to recollect. If not still you can verify it in this lifetime. In a split second the material in our body disintegrates and reforms as part of the dependent arising process. (Process of Consciousness and Matter: The Philosophical Psychology of Buddhism by Rewata Dhamma, page 39, states this is more than 58 billion times a second) This also is verifiable through meditation when you make your mind at least as sharp enough to see Kalapas. Physical death and conception is only a special case in this process.

Answer 5

Rebirth in the traditional sense may or may not happen. Despite what you say about NMR (which I also studied), we don't have any scientific evidence either way. But in the momentary sense, in the sense of being a different person in a different world from one moment to the next, this certainly seems to me to be what happens.

And with respect to the traditional understanding of rebirth, Buddhism's view is that circumstances come and go (are born and die), but that there is something which isn't born and doesn't die. What of this thing that isn't born and doesn't die? What of it before your physical birth, what of it after your physical death?

Answer 6

My person would wonder how alternativ speculations would manifest if thinking on "Where I am from?" with all that individual and unique features.

Would it even cause more suffering as the answers thoughts and approach?

Where or what, are you thinking, that you are from? Maybe you remember if concentration is clear and undisturbed. Of course that requires certain traing and given path. But maybe simply try, to know for you self, even here & now.

For this Dhamma is to be realize for oneself, for the wise, open to get taimed.

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

Answer 7

I've seen people discussing the differences between mind, brain, consciousness, etc. The evidence is now overwhelming that every aspect of the mind is produced by the brain.

Proof can be subjective (everybody expects different sets of evidences). Most of the studies are very limited and based on the wrong scientific assumptions that all matter is unconscious, consciousness is an illusory artefact of the chemical brain and there is no spirit, no mind and nothing other than mechanical and chemical stuff.

There are many hypotheses of our existence and ultimately we can never prove something for 100% as there are always some other factors due to complexity of our reality that we're living. The problem is that a scientific theory must make testable or refutable predictions of what should happen or be seen under a given set of new, independent, observing or analysis circumstances from the particular problem or observation the theory was originally designed to explain. Therefore you can't even prove your own existence. Secondly non-physical spirit world can't be measured using physical instruments, because it doesn't make sense to do that and it goes beyond that.

However there are certain scientific studies which proves otherwise (that mind is produced by the brain), for example Consciousness as a State of Matter (see: video) by Max Tegmark, Professor of Physics at MIT which explains that consciousness can be understood as a state of matter (perceptronium), capable of giving rise to self-awareness and subjectivity.

NMR scanning and did read some hundreds of articles about the subject, and we have a huge, massive consensus that nothing survives our death. Not a force, not a will... Nothing.

Maybe mentioned NMR scanning was not the right tool to measure something out of thin air and giving subjective "prove" that nothing survives after our death based on the failed experiment. There were many attempts using different methods which were actually successful. For example Russian scientist Konstantin Korotkov photographed a person at the moment of his death with a bioelectrographic camera and his Kirlian photography shows the life force of the person leaving the body gradually.

the only part of rebirth that doesn't violate scientific laws is to say that my atoms will be reborn in other creatures and objects

These are wrong assumptions. You need to open your mind and start seeing reality in terms of waves, not the separate atoms (oneness not separateness). Double slit experiment (see: video) gives another clue that it is consciousness that affects our reality and that we are actually living in simulated reality (see: holographic principle). Recent UK, Canadian and Italian study gives evidence that our universe could be a vast and complex hologram where information makes up our 3D 'reality', not atoms it-self.

Professor Skenderis comments: "Einstein’s theory of general relativity explains almost everything large scale in the universe very well, but starts to unravel when examining its origins and mechanisms at quantum level. Scientists have been working for decades to combine Einstein’s theory of gravity and quantum theory. Some believe the concept of a holographic universe has the potential to reconcile the two."

Based on above recent studies, it is suggested that all physical manifestation (including illusional existence of atoms) comes from self-aware consciousness which can be a state of matter.

Science is clear: there's no support of any evidence in its favour, at least not in the way I see people treating the subject.

Science was also clear some time ago that our Earth is flat. If you think the example is too old, what about long-term clarity of science that there are no any planets in our Solar System beyond Pluto due to ultimate trust in modern scientific measurement tools (not to mention wide criticism of researchers who claimed opposite)? Now science found something opposite, that there is actually extra Solar System planet (appeared from nowhere?) and now we need to rewrite a lot of scientific books again.

Therefore please be aware that science is constantly evolving, scientific theories constantly are superseded by new one which are more adequate and it would be very wrong to assume that all current scientific assumptions are fixed (see: superseded scientific theories). Therefore we can't assume that a single body-of-knowledge has the ultimate truth. Science means 'knowledge' and it's about questioning everything and seeing everything from the different point of view based on conclusions given the available data.

As a scientist, I cannot conceive the existence of something we cannot observe or measure that lives on after I die.

There is usually no 'we', as in most cases studies are performed by limited number of people within limited set of conditions on limited number of people (which they barely know) using limited laboratory setups (spirit world doesn't work like that), and other people just reading about their conclusions which are influenced by their own point of view. Then the rest repeating what they've just read without trying to repeat the same study for them-self justifying they won't be able to achieve the same under same laboratory conditions. Furthermore, we tempt to reject any successful metaphysical studies (such as this one) given the fact that we no longer subject metaphysical experiments to the laws of physics. So according to modern scientific logic, if you can't measure something - it doesn't exist, even you can experience it or see it with your own eyes (e.g. Qi Gong experiment).

Same with dreams and thoughts. We know they do exist, but they cannot be measured using physical instruments (we can measure brain waves, but it doesn't prove their existence). This is due to fact that majority experiencing this phenomenon and no one questioning it. Similar with OBE, if more people will experience this in first person, at the end we'll have to accept it as a fact without able to measure it.

So what about changing scientific approach from relying on external sources into experiencing them on your own (similar like with dreams)? Like experiencing flow of energy in your third eye which could not take long time to practice. Many people in the world mastered astral projection which was studied by many scientists in the past with successful results.

So in fact, you can 'observe' this phenomena, however not by using scientific physical instruments, but by experiencing yourself and observing it directly by inducing an OBE via meditation. You can also experience and measure this phenomenon using your own mind-body-spirit complex if we can classify own being as a measuring instrument.

He elucidates reincarnation is not something causal. If there aren't any, why do people still believing in this concept?

People are believing in reincarnation concept, because it makes perfect sense. Based on above mentioned facts and by connecting all the dots together, one can easily come into same logical conclusion without need of blindly following mainstream knowledge.

When you come into realization that consciousness is not only illusory artefact of the chemical brain, but it's omnipresence beyond time and space (where time and space is illusionary construct, even according to Einstein), you will start seeing everything from different angle and your mind's perception will change forever.

A human being is a part of the whole, called by us “Universe,” a part limited in time and space. He experiences himself, his thoughts and feelings as something separate from the rest — a kind of optical delusion of his consciousness. This delusion is a kind of prison for us, restricting us to our personal desires and to affection for a few persons nearest to us. Our task must be to free ourselves from this prison by widening our circle of compassion to embrace all living creatures and the whole of nature in its beauty. ^Einstein

Answer 8

Buddha says the world begins with the six senses. Where there is a formation of the fix senses, there is formation of the world. (Samyutta Nikaya -1 / 1.7.10 - Loka Sutta). Where there is no formation of the six senses, the world ceases to exist (Samyutta Nikaya - 2 / 1.5.4 - Loka Sutta).

Science looks at birth as something that occurs in the world, or universe. Buddhism on the otherhand stipulated that world (universe) as something that occurs with the formation of the six senses. A scientist, looking at this scientifically, will have to agree, or disprove that the world ceases to exist where there is no six senses. A sensible scientist will therefore explore further on the six senses. However, I haven't seen such sensibility so far. Probably due to lack of original Buddhist suttas being available to them.

Reincarnation and consciousness is something even science has no clue on. For example, science has no idea how memory is stored(encoded) except that they know if parts of the brain damage, people lose certain skills (such as when reading they don't see vowels but can see other letters).

There is some hints science has on matters such as mind. For example it suspects that observers (mind, consciousness) defines the state of the observant (Schrödinger's cat).

Buddha speaks of Arya Experimentation. That is, to experiment on understanding the Four Noble Truths. Falling short, you will be contemplating over endless scientific material (as all things that arise are subject to change) forever. A person with common sense therefore, might set that aside and continue on Arya Experimentation.

Answer 9

If you want to study Buddhism from a scientific perspective, you have to follow the evolutionary approach. Human thinking follows an evolutionary process. Religion and philosophy, like political and economic thoughts, have their origin in simpler thoughts of older societies.

Buddhism has evolved out of Hinduism, from the thoughts of Upanishads: Upanishads are philosophies of individual teachers .

These ideas of Upanishads were later systematized and classified, for teaching the basic principles of Hindu philosophy to students. There are six schools of Hindu philosophy, namely: Sankhya; Yoga; Nyaya; Vaisheshika; Purva Mmansa; and Uttara Mimansa.

Uttara Mimansa (also known as Advaita Vedanta) is the source of Buddhist Philosophy.

Advaita Vedanta developed as an attempt to combine the ideas of Sankhya, Yoga and Nyaya systems of philosophies:

• Nyaya system is pure logic, from which mathematics has evolved
• Sankhya system is natural science -- application of logic and mathematics to study nature, and discover laws of nature and laws of astronomy
• Yoga system is study of human psychology.

It is less difficult to use logic and mathematics to study the physical universe, and discover laws governing the material universe. It is much more difficult to combine laws of psychology to formulas of mathematics and laws of the material universe -- to create a comprehensive, long lasting, universally accepted philosophy. Buddhism is one such attempt: which tries to integrate logic, psychology, and laws of material universe.

"Human needs are infinite, but human capacity is finite" is one law of psychology. Human life is finite, but humans want infinite life, eternal life or immortality. It is not possible to find any mathematical formula or scientific law, which can make humans materialize this desire, but there is an incessant demand for it -- from kings and emperors to the Common man and beggars.

Philosophers will have to make a compromise, to satisfy this need: otherwise, people will go to frauds and fake prophets to satisfy this need.

Answer 10

Buddhism was born out of the Sramana movement in India. There were 6 or so Sramana schools during the time of the Buddha. See Wikipedia entry on Sramana. The Ajivika and the Charvaka schools denied the Karma theory whereas the other schools including Jainism and Buddhism adopted this concept. It is interesting to note that all the Sramana schools had one thing in common - deny a creator God. I speculate that Buddha may have been forced to accept the Karma theory because of the prevailing societal conditions, but had no way of reconciling this with the Anatman theory.

Having said that, there were some scientific endeavors in the study of reincarnation - Ian Stevenson had conducted extensive research into reincarnation, but has been met with a lot of skepticism. I suppose it is extremely difficult to prove rebirth from a scientific viewpoint as it involves repeatable experiments, which is not possible in this case.

Answer 11

First of all, I'd like to say I'm a scientist. This means fact will always come before faith, even if it hurts.

Nothing hurts the Buddha. Unlike scientists, most of whom are so crazy that they create atomic weapons & other evil things, the Buddha was fully enlightened with perfect peace.

I'd therefore like to know passages from suttas where Buddha affirms that knowledge of past lives is unattainable

I am not aware of any such passages. The suttas refer to recollecting past abodes or adherences, which means recollecting in the past when the mind ignorantly regarded one or more of the five aggregates to be 'self'. If your mind is intelligent enough, it can read about it in SN 22.79.

or at least where He elucidates reincarnation is not something causal.

The Pali suttas do not contain any systemic explanations of 'reincarnation' (despite the misinterpretations of most 'Buddhists' about dependent origination & other teachings). That is why later-day Buddhists invented their own ideas about reincarnation, such as 'relinking consciousness; mind-stream; storehouse consciousness; bardo', etc.

That said, there are some later-day suttas that refer to literal past lives, such as AN 3.15, MN 50, MN 81, MN 123 & MN 143, however they provide no explanation about how this literal reincarnation occurred. These suttas are similar to later-day 'Jataka' thus is seems unlikely, even impossible, the Lord Buddha spoke them.

Note: These reincarnation suttas contradict other suttas, such as SN 22.79, MN 64, etc.

If there aren't any, why do people still believing in this concept?

Craving.

Only because they feel safer?

Yes, Einstein.