Is it possible to attain stream-entry if one is only following "the 5 precepts"?

Would experiential faith in the Buddha, the Teaching, the Sangha and following the 5 precepts be enough for stream-entry?

I'd like to say "yes" -- and that "experiential faith" is already a lot and must be enough to begin to work with.

What troubles me, about that answer, is that maybe there is something else important -- i.e. meeting or knowing an arya person.

Is it also necessary to to meet or know, interact with, to learn from, to try to help, an arya person? Or is that hard to say?

In the Buddha's day you probably wouldn't hear the dhamma except in person; so the case wouldn't arise (can you even have "experiential faith in the sangha", without meeting "the sangha"?); but now ...

This answer mentions ...

In fact, cleaning the thoughts is really the first time somebody does an activity with good karma, unless there is dana to some arya because this is easier (when aryas are here).

... which I can't deny from experience, and might be canonical.

And granted that, I wonder if that's universally/always another requirement.

A reason I'm not happy with that as an answer ("you need to meet an arya") is that it might lead the question, "how should I meet an arya?", and so on, and heading off to search for one instead of maybe accepting your own knowledge of the dhamma.

I mean it might be a reasonable desire, but it might be a craving and eventually a not-good kind of some guru-worship.

Maybe it's a good thing to think about, though -- people you know who are ethical, people you have known and learned from, or could know.

One can start with the 5 precepts but one has to go through the following milestones along the way:

• beginning with moral virtue, sīla
• would naturally experience non-guilt, avippaṭisāra
• which leads to joy, pamudita
• which leads to zest, pīti
• which leads to a tranquil body, passadha,kāya
• which brings happiness, sukha
• which conduces to mental concentration, samādhi
• which allows us to see true reality, yathā,bhūta
• which leads to revulsion, and nibbidā
• which results in the knowledge and vision of freedom. vimutti,ñāṇa,dassana

Nibbida by Piya Tan

Do to that one has to follow the threefold training (trisikkhā). Sila is only one of the threefold training (trisikkhā):

• higher virtue (adhisīla-sikkhā)
• higher mind (adhicitta-sikkhā)
• higher wisdom (adhipaññā-sikkhā)

In SN55.23 Mahānāma asks about stream-entry. After giving the standard answer of experiential confidence in the Buddha, Teaching and Sangha, Mahānāma persists and asks for more detail. Godha explains further:

“Godhā, a person must have four things for me to recognize them as a stream-enterer. What four? It’s when a noble disciple has experiential confidence in the Buddha … the teaching … the Saṅgha … And they have the ethical conduct loved by the noble ones … leading to immersion. When a person has these four things I recognize them as a stream-enterer.”

Ethical conduct is guided by precepts. Five is a great start. Undertaking more precepts has greater benefit and will deepen study.

Precepts are not about self-mortification. Precepts are guides for wholesome behavior. For example, the precept to not kill might lead one to consider being a vegetarian out of compassion for animals instead of gorging on steak.

Precepts aren't about scoring high on merit--they are just thought guides and references that allow us to examine our motivations with clarity and an open heart.

Therefore to answer your question...

Since the five precepts guide ethical conduct, you would still need the first three things. You would also need experiential faith in the Buddha, the Teaching and the Sangha.

"entering the stream" means you understood the main point of Buddhism and started applying that point to your entire life.

Which point? -- That you should stop creating causes for future dukkha.

Which causes create dukkha? -- Whatever leads to increase of conflict, increase of side-taking, increase of attachment, increase of obsession, increase of aversion, increase of ignorance - leads to increase of dukkha. Whatever leads to maintenance of conflict, maintenance of side-taking, maintenance of attachment, maintenance of obsession, maintenance of aversion, maintenance of ignorance - leads to maintenance of dukkha. Whatever leads to cessation of conflict, cessation of side-taking, cessation of attachment, cessation of obsession, cessation of aversion, cessation of ignorance - leads to cessation of dukkha.

The nature of dukkha is conflict, clash, mismatch - so if you are setting in motion forces that will set up conditions for arising of conflict, clash, mismatch - then that's what you will get. Once you get that - there's suffering. Correspondingly, when you are laying down causes in the here and now that are by nature conducive to harmony - then that's what you'll get. It is that simple. We create Dukkha by ourselves, so once we stop creating Dukkha we may still get some Dukkha created in the past, but eventually all the past causes will run out and the new causes will come to effect, and so gradually we will attain the natural harmonious state - Nirvana.

Once you really "get" this, once you see it clearly, then you stop acting like that, because you know it's for your own benefit. It's not just blindly following the five precepts. It's about getting the principle. Sometimes you may still make mistakes and create trouble - but as long as you got the principle in the overall - you will keep making progress.

This is when we say you are "in the stream" leading to Nirvana.

The Vera Sutta (AN 10.92) (quoted below) lists out the criteria for stream entry:

• Five forms of fear and animosity are stilled (i.e. the effect of consistently and heedfully practising the five precepts)
• Four factors of stream entry
• Rightly seen and rightly ferreted out the noble method (i.e. understood dependent origination thoroughly through insight)

The four factors of stream entry are verified confidence (or experiential confidence) in the Buddha, Dhamma (the teaching) and Sangha, as well as, being endowed with the virtues appealing to the noble ones.

From the Vera Sutta (AN 10.92):

Then Anathapindika the householder went to the Blessed One and, on arrival, having bowed down to the Blessed One, sat to one side. As he was sitting there, the Blessed One said to him, "When, for a disciple of the noble ones, five forms of fear & animosity are stilled; when he is endowed with the four factors of stream-entry; and when, through discernment, he has rightly seen & rightly ferreted out the noble method, then if he wants he may state about himself: 'Hell is ended; animal wombs are ended; the state of the hungry shades is ended; states of deprivation, destitution, the bad bourns are ended! I am a stream-winner, steadfast, never again destined for states of woe, headed for self-awakening!'

"Now, which five forms of fear & animosity are stilled?

"When a person takes life, then with the taking of life as a requisite condition, he produces fear & animosity in the here & now, produces fear & animosity in future lives, experiences mental concomitants of pain & despair; but when he refrains from taking life, he neither produces fear & animosity in the here & now nor does he produce fear & animosity in future lives, nor does he experience mental concomitants of pain & despair: for one who refrains from taking life, that fear & animosity is thus stilled.

"When a person steals... engages in illicit sex... tells lies...

"When a person drinks distilled & fermented drinks that cause heedlessness, then with the drinking of distilled & fermented drinks that cause heedlessness as a requisite condition, he produces fear & animosity in the here & now, produces fear & animosity in future lives, experiences mental concomitants of pain & despair; but when he refrains from drinking distilled & fermented drinks that cause heedlessness, he neither produces fear & animosity in the here & now nor does he produce fear & animosity in future lives, nor does he experience mental concomitants of pain & despair: for one who refrains from drinking distilled & fermented drinks that cause heedlessness, that fear & animosity is thus stilled.

"These are the five forms of fear & animosity that are stilled.

Additional question from a comment:

OP: Would experiential faith in the Buddha, the Teaching, the Sangha and following the 5 precepts be enough for stream-entry?

No. All the criteria listed above are required.