Esse Est Percipi

The Irish philosopher George Berkeley, who became Bishop Berkeley after he took Holy Orders in the Anglican-affiliated Church of Ireland, lived during what was, here on this side of the pond, our colonial period. He eventually gave his name, which was pronounced BARK-lee, to a branch of the University of California and the city that grew up around it, pronounced BERK-lee.

Bishop Berkeley, as a philosopher, objected to some to the ideas that had been put about by John Locke, the British empiricist who was slightly his elder. Locke, in his Essay Concerning Human Understanding (1690), held that many of the qualities we perceive in the objects around us pertain, not the the objects themselves, but to the "ideas" conveyed to us by means of what we today might better call "sense-data." For example, the redness of a red vase is an "idea" that does not belong to the vase per se but inheres in the sense-data that our eyes receive from the vase. (Remember, this was written at a time when science was just beginning to understand about the wavelength composition of light.)

Locke was thus a "dualist" concerning the "reality" of the objects we see. Some of their qualities, such as their weight, in fact inhered in the objects themselves. Other qualities such as color, and also shape, inhered only in the "ideas" conveyed to us from the objects in the form of sense-data. The latter qualities are in some sense bogus: a coin is only round, not oval, if we look at it face on.

Berkeley, on the other hand, was a "subjective idealist," though he himself referred to his view as that of "immaterialism." Where Locke would have said that sense objects have "real" existence and accordingly persist in existence when no one is looking at them, Berkeley's thesis was esse est percipi, to exist is to be perceived.

The notion that things exist independently of outside observation depends on their being made of some sort of ineffable substance or material, beyond their perceptible qualities such as weight or color or shape. If they have mass or weight, their substance gives it to their atoms. If they have color, it reflects how their atoms or electrons are arranged. Substance, if real, is not what atoms are, it is what they have.

We can talk of atoms and electrons and wavelengths today; Locke and Berkeley could not. But never mind; the metaphysical question of the persistent being of objects by virtue of their substance or material "stuff," independently of their being seen, that is, remains the same — a philosophical one, not a scientific one.

Edwards and Pap's A Modern Introduction to Philosophy

Just as in the 17th and 18th centuries, human beings today start out as "naive realists" who believe implicitly that objects exist, even if unseen, and have "just those qualities which they appear to have" (see the Introduction to the section on "Perception and the Physical World" in A Modern Introduction to Philosophy, 3rd Edition, by Paul Edwards and Arthur Pap, p. 568).

Locke in part debunked the second of that pair of beliefs — while still holding that some qualities are real — but Berkeley alone questioned the first. He felt it was

... just as meaningless, or self-contradictory, to suppose that something which is not a mind exists without being perceived, as to suppose the existence of a husband without a wife [p. 571].

In other words, there simply was, for Berkeley, no material substance by which a non-mental object, unperceived by mind, could be said to exist.


Not only does this pronouncement deny our naive realism, it seems to defy our commonsense understanding that the universe was in existence long before any sentient creatures were around to observe it. Berkeley got around this objection in a way I find compelling to the max: he noted that "the material universe has always existed in the divine consciousness" (p. 571, my italics).

I interpret that as meaning that existence is conferred on our material universe by virtue of God's seeing it and observing it. It is in God's mind that the existence of the world and of all the things in it is registered, thereby to be sustained, by an act of conscious observation on God's part. His eye is on the sparrow ... and everything else ... and Berkeley was right: to exist is to be perceived. Or, as I would rather put it, to exist is to be observed.


This seems in fact a corollary of some of the most up to date science we have today. As I reported in Genesis by Observership, a thought experiment dreamed up by physicist John Archibald Wheeler and confirmed indirectly at the University of Maryland shows that quantum events such as photons emitted from distant galaxies don't "choose" which of multiple possible paths to take to the Earth unless and until an observer on our planet aims a telescope at one of those paths, ignoring the others. Another physicist, Andrei Linde, asserts (and here he disagrees with Wheeler) that the act of observation which fixes the photon's path must be done by a conscious observer, not just any mechanical recording device.

If Linde is right, then Berkeley's principle becomes "to exist is to be consciously observed." This, indeed, is my own conviction. I am drawn to it in part because it makes mind or consciousness an equal partner with matter (if not a preexisting, preeminent partner), rather than an illusion of, or an epiphenomenon of, physical activity in a brain.


Furthermore, it squares with my belief in God to think that God's "vision" is fundamentally required if a world is to be created and sustained in existence. It gives a welcome new spin to the religious claim that we conscious humans are made in God's "image" — God possesses a conscious mind, and so do we.

If one act of human observation can "make" a photon choose an intergalactic path that by normal reckoning must have been settled on millions of years ago, there is something going on that our "normal reckoning" boggles at — and our conscious, observing mind is apparently responsible for it. We have an ability that represents some tiny fraction of God's ability to make something "be" just by looking at it.

In future posts I would like to expand upon how a philosophy of esse est percipi, or a modern version thereof, might be able to help bridge the present gaps between philosophy itself, science, and theology.