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Mulla Sadra’s substantial motion: what if things change in their very substance?

Reza Tehrani Fellow
· 4 replies
Existence & beingGreek & RomanIslamicPersianFalsafaTranscendent philosophyAristotleHeraclitusIbn SinaMulla Sadra#change#gradation-of-being#persistence#substantial-motion
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I am an architect in Shiraz, and Mulla Sadra, who was born here, keeps pulling me back to questions about being. This one has been on my mind since I started reading about persistence.

In Aristotle's framework, which Ibn Sina refined, a substance persists while its accidents change. The apple stays an apple while it goes from green to red. Change happens in quality, quantity, place and position, but not in substance itself. Substance either is or is not; coming into being and passing away are instantaneous, not gradual motions.

Mulla Sadra disagreed. He argued for al-ḥaraka al-jawhariyya, substantial motion: the very substance of material things is in continuous renewal. Accidents change because the substance underlying them is itself flowing. The world is not stable things with changing surfaces; it is a process of becoming all the way down.

What fascinates me is how he keeps identity. If the substance is always renewing, what makes it one thing? His answer, as far as I can follow, is that existence itself comes in grades of intensity, and a thing's unity is the unity of one existence intensifying or weakening, like a light growing brighter.

I would like to hear from people who know Ibn Sina's side, and from anyone who sees connections to Heraclitus or to traditions further east. Is this a solution to the problem of persistence, or a way of dissolving it?

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4 replies

  1. Layla Sfeir

    Fellow

    Ibn Sina's reason for denying motion in substance is worth stating, because Mulla Sadra had to overcome it. Motion requires a subject that persists through it. If the substance itself moved, what would be the subject of the motion? There would be nothing that stays put to undergo the change. Mulla Sadra's reply is to make the subject of change not a static substance but existence itself, which can be one while intensifying. Whether that answers Ibn Sina or redefines the terms is exactly where specialists disagree.

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  2. Nikos Theodoridis

    Fellow

    A word of caution about the Heraclitus comparison, which I hear often in Thessaloniki. The fragment we can trust says that on those who step into the same rivers, different and again different waters flow. That keeps the river the same while the water changes. "You cannot step into the same river twice" is Plato's report, and it makes Heraclitus more radical than the fragment does. Mulla Sadra is closer to the fragment: one river, constantly renewing.

  3. Liu Mingqiao

    Fellow

    In Chinese cosmology, Daoist and Confucian alike, everything is the transformation of qi, condensing and dispersing. The Neo-Confucian Zhang Zai in the Song dynasty made this very explicit. I think he and Mulla Sadra would understand each other: no fixed substances, one stuff in continuous process, unity through continuity of the process. The difference is that Mulla Sadra has a direction, toward greater intensity of being, and Daoist transformation does not obviously go anywhere.

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    1. Reza Tehrani

      Fellow

      Liu, that difference is important. For Mulla Sadra substantial motion is also the soul's journey: it begins bodily and becomes more spiritual. Change has a direction. I think that is why I am drawn to him as an architect. A good building is not only a structure that persists; it is a sequence that takes you somewhere.

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