剎那（梵ks!an!a，巴khan!a，藏skad-cig）指極短的時間。依《俱舍論》，一剎那相當於一秒的七十五分之一。《仁王經》云︰「一念中有九十剎那，一剎那經九百生滅」。此外，《大毗婆沙論》卷三十六舉五說。這些經論屬於部派與大乘佛教。在原始佛教的《雜阿含經》，有說 「剎那」與「剎那生滅」嗎？

對照北傳漢譯《雜阿含經》和南傳巴利文的《相應部》，近於「剎那生滅」的說法見於北傳的《雜阿含經》, 而不見於南傳的《相應部》。所以「剎那生滅」的說法應當屬於部派佛教，而且跟說一切有部有關。

What's common between 2 誦本 is the mind changes quickly, much faster than material body change. What's in question is the unit of time for change.

雜阿含290經
愚癡無聞凡夫，寧於四大色身繫我、我所，不可於識繫我、我所。所以者何？四大色身，或見十年住，二十、三十，乃至百年，若善消息，或復少過；彼心、意、識，日夜、時剋，須臾不停，種種轉變，異生異滅。譬如彌猴遊林樹間，須臾處處，攀捉技條，放一取一，彼心、意、識亦復如是，種種變易，異生異滅。

The corresponding Pali SN12.61 reads:
"It would be better for the uninstructed run-of-the-mill person to hold to the body composed of the four great elements, rather than the mind, as the self. Why is that? Because this body composed of the four great elements is seen standing for a year, two years, three, four, five, ten, twenty, thirty, forty, fifty, a hundred years or more. But what's called 'mind,' 'intellect,' or 'consciousness' by day and by night arises as one thing and ceases as another. Just as a monkey, swinging through a forest wilderness, grabs a branch. Letting go of it, it grabs another branch. Letting go of that, it grabs another one. Letting go of that, it grabs another one. In the same way, what's called 'mind,' 'intellect,' or 'consciousness' by day and by night arises as one thing and ceases as another.

雜阿含273經
譬如兩手和合，相對作聲。如是緣眼、色生眼識，三事和合觸，觸俱生受、想、思。此等諸法，非我、非常，是無常 之我，非恆、非安隱、變易之我。所以者何？比丘！謂生、老、死、沒、受生之法。比丘！諸行 如幻，如炎，剎那時頃盡朽，不實來、實去，是故比丘於空諸行，當知、當喜、當念：空諸行， 常、恆、住、不變易法空，無我我所。

273經即『撫掌喻經』，為說一切有部所誦。南傳沒有對應的經文。