Is light a cluster of particles (photons)?

Why I stopped believing that light is a particle (until now)

(Looking Glass Universe) This video is about Richard Feynman's Quantum Electrodynamics (QED), which says that light is made of photons [particles] that go on all possible paths at once.

Einstein: O, Great Buddha, what is the answer?

The experiment in the video is from the following video from Veritasium. Even though I don't agree fully agree with their interpretation of the experiment, I think it's an excellent explanation of QED. I highly recommend it!

• VIDEO: Wave, particle, or wavicle? DIY double-slit light experiment
• VIDEO: The LIGHT science can't explain (sutra)

Something strange happens when you trust quantum mechanics

Light in Buddhist meditation and physics

What is directly-perceived light? It may be kalapas, the smallest units of materiality (rupa, form)

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It is possible to directly perceive light

In Buddhism, āloka-saññā means the "perception of light." A recurring Pali language canon passage reads:

"Here the meditator contemplates the perception of light, fixes mind on the perception of the day, as at daytime so by night, and as at nighttime so by day. In this way, with a mind clear and unclouded, one develops a stage of mind that is full of brightness."

That is, mind becomes full of the perception of light.

This perception is one of the methods for overcoming drowsiness in meditation recommended by the Buddha to the chief male disciple "foremost in psychic powers," Mahā Moggallāna (A.VII. 58). [He may have said the same to the chief female disciple declared "foremost in psychic powers," Uppalavanna Theri.]

Attain absorptions, see kalapa, review in slo-mo

According to DN 33, this method is conducive to the development of "knowledge and vision." (See "purification," visuddhi). And it is said to be helpful for the attainment of the psychic "divine eye." (See abhiññā). Light can also be the direct subject of meditation as a kasina (a disk or special meditation object).

Buddhism has its own physics? Oh, yes. It is called the "Doctrine in Ultimate Terms" or Abhidhamma pitaka. Why? In Buddhism, there is conventional reality as distinct from ultimate reality. In one world or perspective, there are things and persons. In another, there are only ultimate mind and matter, nama and rupa ("name and form") or the ultimate constituents of things, namely cittas ("mind-moments") and kalapas ("particles").

Something strange happens when we trust quantum mechanics

(Veritasium) March 4, 2025: Does light take all possible paths at the same time? Massive thanks to Dr. Andrew Mitchell for his help and expertise. To delve further into this topic, see his lecture on classical physics derived from quantum mechanics: Classical physics derived from quantum...

• 0:00 What path does light travel?
• 2:40 Black body radiation
• 6:47 How did Planck solve the ultraviolet catastrophe?
• 9:42 The quantum of action
• 13:25 De Broglie’s hypothesis
• 15:16 The double slit experiment
• 20:00 How Feynman did quantum mechanics
• 25:01 Proof that light takes every path
• 31:16 The Theory of Everything

Incredible gratitude to Prof. David Kaiser, Prof. Steven Strogatz, Prof. Geraint F. Lewis, Elba Alonso-Monsalve, Prof. Christopher S. Baird, Prof. Anthony Bloch, and Prof. Stephen Bartlett for their invaluable contributions to this video. Special thanks to Mahesh Shenoy from FloatHeadPhysics for his help with this video. Check out his excellent intuitive video on the UV Catastrophe here (Sept. 2024): I wish I was taught the birth of Quan...

• Looking Glass Universe, 3/28/25; Veritasium, 3/4/25; Ven. Nyanatiloka, Buddhist Dictionary, āloka-saññā edited and expanded by Dhr. Seven; Crystal Quintero, CC Liu, Sheldon S. (eds.), Wisdom Quarterly