user16: A claim which is often heard in connection with Buddhism is that it is not a religion. From a scientific point of view, is it a religion, or is it not?

user760: Buddhism is clearly a religion, unless you have a very restrictive definition of religion, such as "belief in a single, omnipotent and personal God", which excludes a wide range of existing belief systems. There is of course Buddhist philosophy (as well as Buddhist psychology and what not), but there are various aspects of Buddhism that are typical only for religions and not for philosophies.
Mainstream Buddhists believe in supernatural entities, such as devas, which are organised in a very elaborate taxonomy, without any clear relation to the observable world. They believe in existence of a huge number of worlds and realms, and despite of lack any empirical evidence, they provide very specific information about them, such as their height. They claim to know what happens after a person dies, again without any empirical evidence. I would say those are features very typical for religions, and untypical for philosophies.
Of course, we may take a liberal definition of Buddhism and include, say, Sam Harris among Buddhists. He is one of the Four Horsemen of the Non-Apocalypse, and explicitly denies beliefs in anything that may be seen as religious. In such case your question doesn't have a good answer other than "it's a religion for some and a philosophy for others". But I wouldn't go that way, as this kind of reasoning can be done with almost any religion. For instance, there are many people who declare themselves Christians, but say that it is not important whether Jesus rose from the dead or not, it is the moral message that matters. For them, Christianity is effectively a moral philosophy and not a religion. So Buddhism does not differ from other religions in that respect.

user-1: It depends on the practitioner.  For me personally, Buddhism is a philosophy and a way of living in harmony with the Dharma.  For others it is a deeply held faith that takes precedence over science.  (See Isn't Buddhist insight practice more scientific than the so-called scientific method?).  There is room for both sorts of people in Buddhism.  Buddhism is like Judaism in that both rely on a source text but the interpretation and practice of the lessons in that text are entirely up to the sangha (Buddhist) or minyan (Jewish), although there is much commentary from learned spiritual people.  Neither has a Pope. :-)

user1094: Buddhism is neither a religion nor a philosophy.
Buddhism can refer to the Truths (Ariyasaccani) (Dhamma) pointed out by Lord Buddha (Buddho Bhagava) to the world and His explanations thereof as given in the Nikaya texts published by the Pali Text Society; or
To the numerous Buddhist traditions, both living and dead. All these traditions arose after the First Council and the before the Second Council (See 2500 Years of Buddhism, Government of India, 1956). 
Almost all these traditions do not acknowledge a 'creator god'nor they worship one.None of them are religions. 
It is needless to say that Dhamma is not a philosophy. It is called a philosophy by people who do not and cannot ever understand Dhamma. This is the reason for numerous 'interpretations' of Dhamma. 

user145: All religions have their philosophies (as metaphysics), so Buddhism is not an exception.
Views are sometimes divided into naive, religious, and philosophy. Where philosophy is  scientific, as opposed to the other two. In that sense, Buddhism is not strictly philosophy because it is not opposed to religion. On the other hand, for ancient people religion was science, and even more for ancient India where pandita was synonym for scholar. Thus, in that sense Buddhism is science and includes philosophy, ethics, soteriology, etc.
So, basically, this question is about splitting intersecting notions. They may be equated or distincted by different criteria, depending on context.

user880: I am convinced that any answer has to give a definition first of “scientific” and of “religion”. 
I consider “religion” a social phenomenon based on three pillars: doctrine, community and cult (see “Joachim Wach: Sociology of Religion”). Moreover, the doctrine should include the belief in one or more beings with superhuman power who affect the life of their believers. 
I consider this definition a “scientific” definition, because one can observe in a given society whether such phenomenon exists. The experts can discuss the findings in an intersubjective manner. Eventually, they can reach a common view about the open questions.
It is not important for my definition whether the statements of the religious doctrine are true or false. I exclude this aspect from my definition because history shows: Questions like that are undecidable.
Applying my definition to Buddhism I tend to the following answer:

Going back as far as possible to the time of the Buddha, Buddhism was no religion. Of course Buddha taught a doctrine (dharma), of course Buddha founded a community (sangha), but Buddha did not emphasize any cult. On the contrary, one of his points was to protest against the Vedic cult. More important: Buddha took an agnostic view concerning the gods under discussion in his time. 
I hope my answer is in agreement with “Richard Gombrich: What the Buddha thought”.
On the other hand, Mahayana buddhism is a fully developed religion which comprises a lot of variations specific to the society under consideration. 


user8157: The original supramundane teachings of the Buddha are neither religion or philosophy. They simply express the true nature of suffering, the cure of suffering & reality. Core Buddhism is like a 'science' in that everything explained in it can be verified by direct insight (rather than are objects of belief or conjecture). 
It was only later in history did Buddhism become a 'religion' of unverifiable beliefs. 
Ultimately, Buddhism is neither religion, philosophy or science but, instead, 'dharma', which means a 'system of understanding & practise that supports freedom from suffering'. The word 'dharma' generically means 'that which supports'. 

user-1: This is a pedantic question in the sense that it focuses on definitions rather than reality. That is the cause of the endless debate. 
Plato is usually counted among the philosophers, but "The Republic" is clearly a religious text in key aspects. The line between religion and philosophy disappears at the deeper levels. Those who explore the edges of what seems to be known are always (by definition?) dabbling in both. 
Take mathematics for example. It is the language of science, however it evolved from Hindu, Pythagorean, and may other religions traditions. 
Alfred North Whitehead and Bertrand Russell tried and failed to prove the fundamental "truthfulness" of mathematics in Principia Mathematica. It has since been mathematically proven that it is impossible to prove the truth of mathematics. This puts all scientific certainty in doubt. Thus, the foundational language of science must itself be taken on faith. 
Furthermore, the scientific faith in the logic of predictability upon which all scientific inquiry is based is scientifically unprovable. Therefore, science itself is a kind of religion based on a solid faith in predictability.
None of this is meant to equate the scientific method with simplistic, magical belief systems. It is simply meant to highlight religious assumptions at the core of the science method. 
Buddhism, with it's emphasis on careful, honest empirical observation, is vulnerable to the same challenge as science. Still, a better method than humble observation does not seem to have been found by humanity, so we bumble along as best we can. To paraphrase Siddhartha Gautama's last words, all we can do is to do our best.

user92: (Disclaimer: Bear in mind this is just a way of seeing things, I have no interest in discussion since it belongs in the chat & this question is very much opinion based. Anyone can argue in which ever way they want and still be supported by references and\or experience.)
Does it have to be one or another? Can't it be both?  
To me it seems a bit of both and I would also add psychology.  

Religion means 'reconnect' and is usually associated with belief, faith & charity.
Psychology is the study of mental & behavioral phenomenon.
Philosophy means 'love for wisdom' and is usually associated with understanding, reasoning & the intellect.  

At the beginning stages of the path, it looks more like a religion because trust (or faith), giving (or charity) & virtue (or morality) are emphasized. These are qualities that 'reconnect' people.  
Further along, it integrates psychology because one makes effort for preventing unwholesome thoughts & developing wholesome ones with the help of mindfulness which then evolves into concentration. These are qualities developed for testing & studying the mind.
Further along, philosophy is integrated because, by now, one knows his own mind very well and so understands which causes give rise to distress & which don't. This is where the path culminates by integrating all three with the complete understanding & realization of the four truths.

user5: I've struggled with this question myself. My opinion is that the problem stems from the fact that the notions of religion and philosophy are purely Western concepts.
Religion, for instance, is term which originated in the Roman Empire, and was used by state powers to legitimize practices such as Judaism and later Christianity (Islam had not developed at the time). Conversely, other practices (e.g. pagan practices, animistic belief systems) lacked such endorsement and were legally open to persecution. In a way, the word "religion" can be seen as the particular superstition which is endorsed by the state.
From Wikipedia:

Julius Caesar formulated a policy of allowing Jews to follow their
  traditional religious practices,a policy which was followed, and
  extended, by Augustus, first emperor of Rome, reigned 27 BC - 14 AD.
  This gave Judaism the status of a religio licita (permitted religion)
  throughout the Empire.

It would be interesting to see a similar treatment with the word Philosophy, but I'm not informed on that topic.
In summary, I'm in agreement with CrabBucket that Buddhism is in a gray area. Buddhism has a strong resemblance to both religion and philosophy, with elements of both, but not adhering strictly to either one.
On the other hand, in modern times people use the word "religion" in the sense of world religions. In this case, the word describes practices that are similar, but which do not share essential qualities that somehow make them religions.

user538: Buddhism is a framework implemented by religions.
From my Mac's dictionary:

framework |ˈfreɪmwəːk|
  noun
  • a basic structure underlying a system,
  concept, or text : the theoretical framework of political sociology.

I'd add to that, that the main difference between a philosophy and a framework is that a framework provides or suggests tools/methods based on its philosophy.
Buddhism the framework is the 4 Noble Truths, a collection of observations and logical conclusions (the first 3 "truths") with the methods/tools supplied in the 4th Noble Truth. To accept/follow/implement the 4 Noble Truths is what makes something "Buddhist" - not just for a person but for any system of thought, including religions.
Several religions have incorporated this and become Buddhist religions:

Hinduism + Buddhist framework == Indian Buddhism (the historical "original").
Daoism + (Indian) Buddhism == Ch'an (or Chinese Buddhism).
Shinto + (Ch'an) Buddhism == Zen.
Bon + (Indian) Buddhism == Tibetan Buddhism.

I'm being a tad simplistic in the depiction of the flavours of Buddhism, but the main thing is, it works as an explanation. Once you know to separate out the framework from the religion it's easy to see why it gets confused as a philosophy by some and a religion by others.

user157: It really depends which definition of religion you go for. For instance

Human recognition of superhuman controlling power and particularly of
a personal God [..]
Oxford English Dictionary.

Buddhism is not a religion based on this definition

Any specific system belief or worship, often involving a code of
ethics and a philosophy
Websters New World Dictionary

Buddhism is a religion based on this definition
(Both quotes are taken from Jared Diamond's the world until yesterday pp 327)
Buddhism certainly is in a grey area with definitions. But then so are other philosophies/religions. Confucianism was considered a religion a few decades ago whereas now it is definitely seen as a philosophy (Jared Diamond again). Shintoism is simliar in the grey area. Going further back then Epicurianism, Stoicism and Neoplatonism all have something about the religious to them but are always (in my reading) spoken about as philosophies.
I would contend that the philosophy/religion divide is a continuum and owes something to the prevailing cultural climate. Nobody would say Marxism is a religion but there is certainly a religious attitude (controversial final point!)
Footnote
Well not quite the final point. Again Jared Diamond - he has 16 definitions for religion on pp 327 of World until Yesterday. It's an interesting exercise to go through them all and see if Buddhism fit's into each definition. It varies quite a bit. For instance just to give one more
Émile_Durkheim

A religion is a unified system of beliefs and practices relative to
sacred things, i.e., things set apart and forbidden--beliefs and
practices which unite in one single moral community called a Church,
all those who adhere to them.

Well maybe, maybe not.

16: <p>A claim which is often heard in connection with Buddhism is that it is not a religion. From a scientific point of view, is it a religion, or is it not?</p>
 760: <p>Buddhism is clearly a religion, unless you have a very restrictive definition of religion, such as "belief in a single, omnipotent and personal God", which excludes a wide range of existing belief systems. There is of course Buddhist philosophy (as well as Buddhist psychology and what not), but there are various aspects of Buddhism that are typical only for religions and not for philosophies.</p>

<p>Mainstream Buddhists believe in supernatural entities, such as devas, which are organised in a very elaborate taxonomy, without any clear relation to the observable world. They believe in existence of a huge number of worlds and realms, and despite of lack any empirical evidence, they provide very specific information about them, such as their height. They claim to know what happens after a person dies, again without any empirical evidence. I would say those are features very typical for religions, and untypical for philosophies.</p>

<p>Of course, we may take a liberal definition of Buddhism and include, say, <a href="http://en.wikipedia.org/wiki/Sam_Harris_%28author%29" rel="nofollow">Sam Harris</a> among Buddhists. He is one of the <a href="http://en.wikipedia.org/wiki/New_Atheism#Four_Horsemen_of_the_Non-Apocalypse" rel="nofollow">Four Horsemen of the Non-Apocalypse</a>, and explicitly denies beliefs in anything that may be seen as religious. In such case your question doesn't have a good answer other than "it's a religion for some and a philosophy for others". But I wouldn't go that way, as this kind of reasoning can be done with almost any religion. For instance, there are many people who declare themselves Christians, but say that it is not important whether Jesus rose from the dead or not, it is the moral message that matters. For them, Christianity is effectively a moral philosophy and not a religion. So Buddhism does not differ from other religions in that respect.</p>
 -1: <p>It depends on the practitioner.  For me personally, Buddhism is a philosophy and a way of living in harmony with the Dharma.  For others it is a deeply held faith that takes precedence over science.  (See <a href="https://buddhism.stackexchange.com/questions/1684/is-knowledge-gained-through-buddhist-practice-considered-more-reliable-than-that">Isn&#39;t Buddhist insight practice more scientific than the so-called scientific method?</a>).  There is room for both sorts of people in Buddhism.  Buddhism is like Judaism in that both rely on a source text but the interpretation and practice of the lessons in that text are entirely up to the sangha (Buddhist) or minyan (Jewish), although there is much commentary from learned spiritual people.  Neither has a Pope. :-)</p>
 1094: <p>Buddhism is neither a religion nor a philosophy.</p>

<p>Buddhism can refer to the Truths (Ariyasaccani) (Dhamma) pointed out by Lord Buddha (Buddho Bhagava) to the world and His explanations thereof as given in the Nikaya texts published by the Pali Text Society; or
To the numerous Buddhist traditions, both living and dead. All these traditions arose after the First Council and the before the Second Council (See 2500 Years of Buddhism, Government of India, 1956). </p>

<p>Almost all these traditions do not acknowledge a 'creator god'nor they worship one.None of them are religions. </p>

<p>It is needless to say that Dhamma is not a philosophy. It is called a philosophy by people who do not and cannot ever understand Dhamma. This is the reason for numerous 'interpretations' of Dhamma. </p>
 145: <p>All religions have their philosophies (as metaphysics), so Buddhism is not an exception.</p>

<p>Views are sometimes divided into <em>naive, religious</em>, and <em>philosophy</em>. Where philosophy is  <em>scientific</em>, as opposed to the other two. In that sense, Buddhism is not strictly philosophy because it is not opposed to <em>religion</em>. On the other hand, for ancient people religion was science, and even more for ancient India where <em>pandita</em> was synonym for scholar. Thus, in that sense Buddhism is science and <em>includes</em> philosophy, ethics, soteriology, etc.</p>

<p>So, basically, this question is about splitting intersecting notions. They may be <em>equated</em> or <em>distincted</em> by different criteria, depending on context.</p>
 880: <p>I am convinced that any answer has to give a definition first of “scientific” and of “religion”. </p>

<p>I consider “religion” a social phenomenon based on three pillars: doctrine, community and cult (see “Joachim Wach: Sociology of Religion”). Moreover, the doctrine should include the belief in one or more beings with superhuman power who affect the life of their believers. </p>

<p>I consider this definition a “scientific” definition, because one can observe in a given society whether such phenomenon exists. The experts can discuss the findings in an intersubjective manner. Eventually, they can reach a common view about the open questions.</p>

<p>It is not important for my definition whether the statements of the religious doctrine are true or false. I exclude this aspect from my definition because history shows: Questions like that are undecidable.</p>

<p>Applying my definition to Buddhism I tend to the following answer:</p>

<ol>
<li><p>Going back as far as possible to the time of the Buddha, Buddhism was no religion. Of course Buddha taught a doctrine (dharma), of course Buddha founded a community (sangha), but Buddha did not emphasize any cult. On the contrary, one of his points was to protest against the Vedic cult. More important: Buddha took an agnostic view concerning the gods under discussion in his time. 
I hope my answer is in agreement with “Richard Gombrich: What the Buddha thought”.</p></li>
<li><p>On the other hand, Mahayana buddhism is a fully developed religion which comprises a lot of variations specific to the society under consideration. </p></li>
</ol>
 8157: <p>The original supramundane teachings of the Buddha are neither religion or philosophy. They simply express the true nature of suffering, the cure of suffering &amp; reality. Core Buddhism is like a 'science' in that everything explained in it can be verified by direct insight (rather than are objects of belief or conjecture). </p>

<p>It was only later in history did Buddhism become a 'religion' of unverifiable beliefs. </p>

<p>Ultimately, Buddhism is neither religion, philosophy or science but, instead, 'dharma', which means a 'system of understanding &amp; practise that supports freedom from suffering'. The word 'dharma' generically means 'that which supports'. </p>
 -1: <p>This is a pedantic question in the sense that it focuses on definitions rather than reality. That is the cause of the endless debate. </p>

<p>Plato is usually counted among the philosophers, but "The Republic" is clearly a religious text in key aspects. The line between religion and philosophy disappears at the deeper levels. Those who explore the edges of what seems to be known are always (by definition?) dabbling in both. </p>

<p>Take mathematics for example. It is the language of science, however it evolved from Hindu, Pythagorean, and may other religions traditions. </p>

<p>Alfred North Whitehead and Bertrand Russell tried and failed to prove the fundamental "truthfulness" of mathematics in <em>Principia Mathematica</em>. It has since been mathematically <em>proven</em> that it is impossible to prove the truth of mathematics. This puts all scientific <em>certainty</em> in doubt. Thus, the foundational language of science must itself be taken on faith. </p>

<p>Furthermore, the scientific faith in the logic of predictability upon which all scientific inquiry is based is scientifically unprovable. Therefore, science itself is a kind of religion based on a solid faith in predictability.</p>

<p>None of this is meant to equate the scientific method with simplistic, magical belief systems. It is simply meant to highlight religious assumptions at the core of the science method. </p>

<p>Buddhism, with it's emphasis on careful, honest empirical observation, is vulnerable to the same challenge as science. Still, a better method than humble observation does not seem to have been found by humanity, so we bumble along as best we can. To paraphrase Siddhartha Gautama's last words, all we can do is to do our best.</p>
 92: <p><em>(Disclaimer: Bear in mind this is just a way of seeing things, I have no interest in discussion since it belongs in the chat &amp; this question is very much opinion based. Anyone can argue in which ever way they want and still be supported by references and\or experience.)</em></p>

<p>Does it have to be one or another? Can't it be both?  </p>

<p>To me it seems a bit of both and I would also add psychology.  </p>

<ol>
<li>Religion means 'reconnect' and is usually associated with belief, faith &amp; charity.</li>
<li>Psychology is the study of mental &amp; behavioral phenomenon.</li>
<li>Philosophy means 'love for wisdom' and is usually associated with understanding, reasoning &amp; the intellect.  </li>
</ol>

<p>At the beginning stages of the path, it looks more like a religion because trust (or faith), giving (or charity) &amp; virtue (or morality) are emphasized. These are qualities that 'reconnect' people.  </p>

<p>Further along, it integrates psychology because one makes effort for preventing unwholesome thoughts &amp; developing wholesome ones with the help of mindfulness which then evolves into concentration. These are qualities developed for testing &amp; studying the mind.</p>

<p>Further along, philosophy is integrated because, by now, one knows his own mind very well and so understands which causes give rise to distress &amp; which don't. This is where the path culminates by integrating all three with the complete understanding &amp; realization of the four truths.</p>
 5: <p>I've struggled with this question myself. My opinion is that the problem stems from the fact that the notions of religion and philosophy are purely Western concepts.</p>

<p>Religion, for instance, is term which originated in the Roman Empire, and was used by state powers to legitimize practices such as Judaism and later Christianity (Islam had not developed at the time). Conversely, other practices (e.g. pagan practices, animistic belief systems) lacked such endorsement and were legally open to persecution. In a way, the word "religion" can be seen as the particular superstition which is endorsed by the state.</p>

<p>From <a href="http://en.wikipedia.org/wiki/History_of_the_Jews_in_the_Roman_Empire#Jews_in_Rome_and_Romans_in_Jerusalem" rel="noreferrer">Wikipedia</a>:</p>

<blockquote>
  <p>Julius Caesar formulated a policy of allowing Jews to follow their
  traditional religious practices,a policy which was followed, and
  extended, by Augustus, first emperor of Rome, reigned 27 BC - 14 AD.
  This gave Judaism the status of a <em>religio licita</em> (permitted religion)
  throughout the Empire.</p>
</blockquote>

<p>It would be interesting to see a similar treatment with the word Philosophy, but I'm not informed on that topic.</p>

<p>In summary, I'm in agreement with CrabBucket that Buddhism is in a gray area. Buddhism has a strong resemblance to both religion and philosophy, with elements of both, but not adhering strictly to either one.</p>

<p>On the other hand, in modern times people use the word "religion" in the sense of world religions. In this case, the word describes practices that are similar, but which do not share essential qualities that somehow make them religions.</p>
 538: <p>Buddhism is a <em>framework</em> implemented by religions.</p>

<p>From my Mac's dictionary:</p>

<blockquote>
  <p>framework |ˈfreɪmwəːk|<br>
  noun<br>
  • a basic structure underlying a system,
  concept, or text : the theoretical framework of political sociology.</p>
</blockquote>

<p>I'd add to that, that the main difference between a philosophy and a framework is that a framework provides or suggests tools/methods based on its philosophy.</p>

<p>Buddhism the <em>framework</em> is the <a href="https://en.wikipedia.org/wiki/4_Noble_Truths" rel="nofollow">4 Noble Truths</a>, a collection of observations and logical conclusions (the first 3 "truths") with the methods/tools supplied in the 4th Noble Truth. To accept/follow/implement the 4 Noble Truths is what makes something "Buddhist" - not just for a person but for any system of thought, including religions.</p>

<p>Several religions have incorporated this and become Buddhist religions:</p>

<ul>
<li>Hinduism + Buddhist framework == Indian Buddhism (the historical "original").</li>
<li>Daoism + (Indian) Buddhism == Ch'an (or Chinese Buddhism).</li>
<li>Shinto + (Ch'an) Buddhism == Zen.</li>
<li>Bon + (Indian) Buddhism == Tibetan Buddhism.</li>
</ul>

<p>I'm being a tad simplistic in the depiction of the flavours of Buddhism, but the main thing is, it works as an explanation. Once you know to separate out the framework from the religion it's easy to see why it gets confused as a philosophy by some and a religion by others.</p>
 157: <p>It really depends which definition of religion you go for. For instance</p>
<blockquote>
<p>Human recognition of superhuman controlling power and particularly of
a personal God [..]</p>
<p>Oxford English Dictionary.</p>
</blockquote>
<p><em><strong>Buddhism is not a religion based on this definition</strong></em></p>
<blockquote>
<p>Any specific system belief or worship, often involving a code of
ethics and a philosophy</p>
<p>Websters New World Dictionary</p>
</blockquote>
<p><em><strong>Buddhism is a religion based on this definition</strong></em></p>
<p>(Both quotes are taken from <a href="http://www.amazon.co.uk/The-World-Until-Yesterday-Traditional/dp/0141024488" rel="noreferrer">Jared Diamond's the world until yesterday</a> pp 327)</p>
<p>Buddhism certainly is in a grey area with definitions. But then so are other philosophies/religions. Confucianism was considered a religion a few decades ago whereas now it is definitely seen as a philosophy (Jared Diamond again). <a href="http://en.wikipedia.org/wiki/Shinto" rel="noreferrer">Shintoism</a> is simliar in the grey area. Going further back then <a href="http://en.wikipedia.org/wiki/Epicureanism" rel="noreferrer">Epicurianism</a>, <a href="http://en.wikipedia.org/wiki/Stoicism" rel="noreferrer">Stoicism</a> and <a href="http://en.wikipedia.org/wiki/Neoplatonism" rel="noreferrer">Neoplatonism</a> all have something about the religious to them but are always (in my reading) spoken about as philosophies.</p>
<p>I would contend that the philosophy/religion divide is a continuum and owes something to the prevailing cultural climate. Nobody would say <a href="http://en.wikipedia.org/wiki/Marxism" rel="noreferrer">Marxism</a> is a religion but there is certainly a religious attitude (controversial final point!)</p>
<p><strong>Footnote</strong></p>
<p>Well not quite the final point. Again Jared Diamond - he has 16 definitions for religion on pp 327 of World until Yesterday. It's an interesting exercise to go through them all and see if Buddhism fit's into each definition. It varies quite a bit. For instance just to give one more</p>
<p><a href="https://en.wikipedia.org/wiki/%C3%89mile_Durkheim" rel="noreferrer">Émile_Durkheim</a></p>
<blockquote>
<p>A religion is a unified system of beliefs and practices relative to
sacred things, i.e., things set apart and forbidden--beliefs and
practices which unite in one single moral community called a Church,
all those who adhere to them.</p>
</blockquote>
<p>Well maybe, maybe not.</p>
