No, of course Freud didn't write anything about the iPad. But an obscure 1925 essay on the "Mystic Pad" gives us some clues as to what he would have made of modern computing technologies.
In 1925, Sigmund Freud published an essay, "A Note upon the 'Mystic Writing Pad.' " In it, he considered a recent market arrival, the Mystic Writing Pad (of course), as a sort of metaphor for the human mind.
At base, the Mystic Pad was "a slab of dark brown resin or wax" on which sat a translucent sheet of wax paper covered by a transparent sheet of celluloid. When a person set a stylus to it, the dark resin would become visible through the wax paper at the points of contact, and thus one could write. When the record was no longer desired, erase it by simply lifting the wax paper off of the slab. (This contemporary kids' toy is a rough equivalent.) The celluloid served merely to protect the wax paper from ripping as the stylus ran across it.
This may not sound like much of a metaphor for the human mind, but one unintended consequence of this procedure struck Freud as quite significant: "The permanent trace of what was written is retained upon the wax slab itself and is legible in suitable lights." The Mystic Pad had a particular kind of memory.
"I do not think it is too far-fetched," Freud wrote, "to compare the celluloid and waxed paper cover with the system of Pcpt.-Cs. [Perception -Consciousness] and its protective shield, the wax slab with the unconscious behind them, and the appearance and disappearance of the writing with the flickering-up and passing-away of consciousness in the process of perception."
For Freud, this was new, as far as technology metaphors go. The other two major technologies he examines in his essay -- paper and slate -- he scrutinizes not so much as a metaphor for the mind, but in their capacity as memory aids or, "mnemic apparatus," as Freud calls them.
"Measured by this standard," Freud wrote, "devices to aid our memory seem particularly imperfect, since our mental apparatus accomplishes precisely what they cannot."
The first, paper and pen, preserves a thought -- a "permanent memory-trace" -- but it is finite and "the receptive capacity of the writing surface is soon exhausted." You then need more paper and more paper, a system for tracking it all, and you may soon lost track of these recorded memories, and forget they exist altogether, thereby negating the value of having recorded it in the first place. A slate, on the other hand, can be used over and over but nothing lasts very long. "Thus," Freud concluded, "an unlimited receptive capacity and a retention of permanent traces seem to be mutually exclusive properties in the apparatus which we use as substitutes for our memory: either the receptive surface must be renewed or the note must be destroyed."
Compare these technologies -- the slate and the pad of paper -- with the other "auxiliary apparatus" humans have designed to improve their sensory abilities: spectacles to improve vision or ear-trumpets for hearing. "Measured by this standard," Freud noted, "devices to aid our memory seem particularly imperfect, since our mental apparatus accomplishes precisely what they cannot: it has an unlimited receptive capacity for new perceptions and nevertheless lays down permanent -- even though not unalterable -- memory-traces of them."
This was why the Mystic Pad so intrigued Freud: It was a more precise analog of the mind's abilities. Like the Mystic Pad, "the perceptive apparatus of our mind consists of two layers," he observed, "of an external protective shield against stimuli whose task it is to diminish the strength of excitations coming in, and of a surface behind it which receives the stimuli." Spectacles, ear-trumpets, and the Mystic Pad all measured up to the human standard: By being like a human's abilities, they were well-suited to extending those abilities.
In that sense, computers are the perfect device for assisting our memories. They manage to solve Freud's conundrum: They have both an "unlimited receptive capacity for new perceptions" (more or less), and the ability to preserve "memory-traces" of them.
But like telescopes or microscopes that enable us to see beyond human perception, modern computing offers a mnemic capacity far more powerful than your average human's: The memories it stores are preserved intact, not as impressions. It may similarly have layers of input and storage, but little is lost in the transfer, and information can be recalled (whether from a hard drive or the cloud) in the same state as it went in (assuming nothing has gone wrong).
By extending Freud's metaphor to today's devices, another insight from the Mystic Pad essay becomes apparent, though Freud didn't make much of it at the time. What makes the human mind distinct isn't just its "layers" for perception and storage, but the imperfections in that system. Though we build ever more perfect memory devices, we can't replicate what makes us us: our flaws.