We’d made the point that it seemed to be very bold of Ramchal to say that the Sephirot could be “envisioned”, but that in fact others had said so as well or spoke of other very sublime visions some were privileged to have had, so let’s explore some of that.
Several sources address the sublime visions that many have had. Sefer Bahir (47) speaks of the celestial phenomena that our people observed at Mount Sinai, which another source refers to as the moment when God Himself appeared to them, albeit covered over by a tallit (Rosh Hashanah 17b) . We’re taught that the very humblest of our people “saw (mystical visions) at the Red Sea that even Isaiah, Ezekiel and all the other prophets weren’t able to see” (Mechilta); and that Moses as well as Nadav and Avihu were able to see the Shechina (which is itself a depiction of the Sephira of Malchut) at the dedication of the Tabernacle (Shemot Rabbah 3:2) as were all who entered into it afterwards (Pesikta D’Rav Kahana), and as the entire Jewish Nation was able to do all together at the dedication of the Holy Temple (Mo’ed Kattan 9a).
Weren’t we told outright that Daniel caught sight of “the Ancient of Days (sitting upon His throne with) His raiment as white as snow, and the hair of His head like clean wool” (Daniel 7:9)? And haven’t we been taught that all the prophets saw celestial phenomena indeed, though through a translucent glass, while Moses saw greater things himself as if looking through a transparent glass (Vayikra Rabbah 1:14)?
Hence, a lot has been seen. Finally, as to prophets envisioning the Sephirot themselves, the Tikkunei Zohar says explicitly that Ezekiel perceived them (p. 2a; also see Zohar 3, 226b). And the Zohar itself alludes to the possibility of perceiving the Sephirot once they draw closer to the physical universe , much the way one is only able to take hold of water that’s spilling down from up above once it falls to the ground (Zohar 2, 42b) .
So we see that Ramchal’s claim isn’t all original; it seems that it was simply the explicitness of the claim that shocked some.
 That itself is a clear reference to envisioning the Sephirot or some other representation, given that God Himself isn’t visible.
 I.e., once the Sephira of Malchut comes into play, as Ramchal himself explains in Petach 9.
 Also see Zohar 2, 270b; and 3, 239a. See Adir Bamarom pp. 37-38 where Ramchal discusses rare individuals who are able to see great visions while in deserts and in fields.
(c) 2011 Rabbi Yaakov Feldman
Feel free to contact me at firstname.lastname@example.org
AT LONG LAST! Rabbi Feldman’s translation of Maimonides’ “Eight Chapters” is available here at a discount.
You can still purchase a copy of Rabbi Feldman’s translation of “The Gates of Repentance” here at a discount as well.
Rabbi Yaakov Feldman has also translated and commented upon “The Path of the Just” and “The Duties of the Heart” (Jason Aronson Publishers).