"The aristocratic view of contemplative asceticism reappears in the doctrine of Meister Eckhart. Like Buddha, Eckhart addressed the noble man and the 'noble soul' whose metaphysical dignity is witnessed by the presence of a 'strength,' a 'light,' and a 'fire' within it—in other words, of something before which even the deity conceived as a 'person' (i.e., theistically) becomes something exterior. The method he employed consisted of detachment from all things (Abegescheidenheit), a virtue that according to Eckhart is above love, humility, or mercifulness, as he explained in his sermon On Detachment. The principle of 'spiritual centrality' was affirmed: the true Self is God, God is our real center and we are external only to ourselves. Fear, hope, anguish, joy, and pain, or anything that may bring us out of ourselves, must be allowed to seep into us. An action dictated by desire, even when its goal is the kingdom of heaven itself, eternal life, or the beatific vision, must not be undertaken. The path suggested by Eckhart leads from the outside to the inside, beyond everything that is mere 'image'; beyond things and what represents the quality of a thing (Dingheit); beyond forms and quality of form (Formlichkeit); beyond essences and essentially. From the gradual extinction of all images and forms, and eventually of one's own thoughts, will, and knowledge, what arises is a transformed and supernatural knowledge that is carried beyond an forms (überformt). Thus one reaches a peak in respect to which 'God' himself (always according to his theistic view) appears as something ephemeral, that is, as a transcendent and uncreated peak of the Self without which 'God' himself could not exist. All the typical images of the religious consciousness are swallowed up by a reality that is an absolute, pure possession, and that in its simplicity cannot help but appear terrifying to any finite being. Once again we find a solar symbol: before this barren and absolute substance, 'God' appears as the moon next to the sun. The divine light in comparison with the radiance of this substance pales, just as the sun's light outshines the moon's."

- Julius Evola in Revolt Against the Modern World

One of the long-lasting legacies of Alexander's Indian conquests was a later East-West cultural syncretism creating a Greco-Buddhist art. Compare the above Gandhara Buddha with this Alexander-Helios image.

Gilt-silver roundel engraved with Alexander Helios, Hellenistic, 4th c. BC

The Śākya: A Solar Tribe

The Śākya: A Solar Tribe

The Śākya were an Indo-Aryan tribe of Iron Age India, habitating the area situated at present-day Nepal and Northern India, near the Himalaya, ruling over an independent state known as Śākya Gaṇarājya.

The Shakyas were by tradition Sun Worshippers, who called themselves Ādicca Nāma Gottena meaning "Kinsmen of the Sun" or "Descendants of the Sun". As Buddha Śākyamuni states in the Sutta-Nipāta: "They are Ādicca by clan. Śākiya by birth"

The Śākya are mentioned in Buddhist texts, including the Mahāvastu, Mahāvaṃsa and Sumaṅgalavilāsinī, a commentary by the monk Buddhaghoṣa on the Digha Nikaya, mostly in the accounts of the birth of the Buddha, as a part of the Ādicchabandhus or the Ādichchas and as descendants of the legendary King Ikśvaku. The Buddhacarita of Aśvaghoṣa gives the following account:

"There lived once upon a time a king of the Śākya, a scion of the solar race, whose name was Suddhodana. He was pure in conduct and beloved of the Śākya like the autumn moon. He had a wife, splendid, beautiful, and steadfast, who was called the Great Maya, from her resemblance to Maya the Goddess."

It's worth nothing the Ādichchas label is the pali equivalent to Ādityas, the offspring of the Vedic Goddess Aditi, Gods that, in conjunction, are associated with the solar cycles, and the Mahāniddesa commentary makes a direct link between the epithet and the Sun God Sūrya.

Buddhaghoṣa's work traces the origin of the Śākya to king Ikśvaku and gives their genealogy from Mahā Sammata, an ancestor of Ikśvaku. This list comprises the names of a number of prominent kings of the Ikśvaku dynasty, which include Mandhata and Sagara. According to this text, Okkamukha was the eldest son of Ikśvaku. Sivisamjaya and Sihassara were the son and grandson of Okkamukha. King Sihassara had eighty-two thousand sons and grandsons, who were together known as the Śākya.

The name Angīrasa (descendant of Áṅgira) was applied to the Buddha several times in the Pitakas. In some texts, it is said that Angīrasa was a personal name given by the Buddha’s father in addition to Siddhartha, sometimes Siddhartha is referred to as Angīrasa Kumāra. According to Vedic tradition, the Śākya belonged to the Gautama Gotra, who belonged to the Angīrasa tribe; the word, as applied to the Buddha, therefore, is probably a patronymic, meaning the clan of the Buddha claimed to be descent from the Vedic Rishi Áṅgira via the gotra lineage of Maharṣiḥ Gautama.

Early Buddhism is full of solar symbolism, with the Buddha or his doctrine usually equated to great radiance. The following passage can be read from the Divyāvadāna:

"Where those Lights of the world, Krakucchanda, Konākamuni, and the
great seer Kasyapa, came and achieved enlightenment, to that place has come this Light of the world, the world’s Guide, he who is the foremost seer of the Śākya, kinsmen of the sun"

In tantric Buddhist traditions, the identification of a Buddha with the sun is very explicit in various figures, such as two of the Five Pañcatathāgatas, Vairocana, the central Buddha in the Cosmic Dhyāni Mandala, and Dharmakāya aspect in certain tantric cycles, who's name literally means "solar" or "sun", and that is sometimes reckoned as the solar source from which Buddhas and Bodhisattvas shine forth as rays of light. The other figure is Amitābha, meaning "infinite light", the lord of the western sector of the Dhyāni Mandala, also considered the Dharmakāya embodiment in his own tantric systems, often symbolically described as a sun.

It's clear Buddhism was greatly influenced by the Indo-Aryan solar worship of the Śākya, and it could even be seen as a continuation of it in many ways from Early Buddhism to the later Vajrayāna tradition.

"On the General Science of Mathematics is the third of four surviving works out of ten by Iamblichus (c. 245 CE–early 320s) on the Pythagoreans. He thought the Pythagoreans had treated mathematics as essential for drawing the human soul upwards to higher realms described by Plato, and downwards to understand the physical cosmos, the products of arts and crafts and the order required for an ethical life.

His Pythagorean treatises use edited quotation to re-tell the history of philosophy, presenting Plato and Aristotle as passing on the ideas invented by Pythagoras and his early followers. Although his quotations tend to come instead from Plato and later Pythagoreanising Platonists, this re-interpretation had a huge impact on the Neoplatonist commentators in Athens. Iamblichus' cleverness, if not to the same extent his re-interpretation, was appreciated by the commentators in Alexandria."

Good article by Edward Feser that covers the concept of the One and apophatic theology within Neoplatonism and relates it to Taoism, interesting read.

https://edwardfeser.blogspot.com/2021/09/lao-tzus-negative-theology.html?m=1