Lecture 4-1: Omniscience — God's Exhaustive and Personal Knowledge

The classical doctrine stated

The traditional formulation, shared across the Reformed, Lutheran, and Catholic streams of this course's readership, holds that God's knowledge has three properties at once, and it is worth separating them because each answers a different objection. First, God's knowledge is exhaustive: he knows all things — every actual event past, present, and future, every possible event that never occurs, and (per the Molinist proposal examined fully in Chapter 8) on some accounts even what any free creature would freely choose under any circumstance that never comes to pass. Second, God's knowledge is certain: God does not merely have well-grounded beliefs or high-probability estimates about the future; what God knows will occur, occurs, without exception, because God's knowledge does not depend on inference from evidence the way human knowledge does. Third, and this is the point Psalm 139 forces onto the table before any of the philosophical machinery, God's knowledge is personal: it is not knowledge of facts about a person collected from a distance but knowledge of the person, the way "I know my father's arthritis" and "I know my father" are different kinds of statements about the same man.

Aquinas grounds exhaustive divine knowledge in God's own being rather than in God's access to an external world of facts. Because God is the cause of all that exists, and because God's knowledge of a thing is (on Aquinas's account) not derived by looking at the thing but is bound up with God's causing it to be, God's knowledge is not limited by anything outside himself the way a human knower's information is limited by what evidence happens to reach them. Calvin, writing four centuries later and far more interested in Scripture's own vocabulary than in the metaphysics of divine causation, arrives at exhaustive foreknowledge from a different direction: the sheer weight of biblical texts in which God announces the outcome of events — including free human choices — before they occur (Isaiah 46:9-10, engaged fully in Chapter 7, is Calvin's characteristic proof text). Aquinas and Calvin disagree about a great deal in this course, but on the bare claim that God knows the future exhaustively and with certainty, they are not disagreeing with each other at all; they are both disagreeing, centuries in advance, with open theism.

Why "exhaustive knowledge of many facts" is not yet the whole doctrine

It would be possible to affirm everything in the paragraph above and still miss what Psalm 139 is actually claiming. The psalm does not open with a claim about the extent of God's information ("Yahweh knows everything that has ever happened"); it opens with a claim about being searched ("Yahweh, you have searched me, and you know me"). The Hebrew verb behind "searched" carries the sense of a careful, deliberate investigation — not indifferent omniscience passing over the psalmist the way a camera passes over a room, but attention that is directed, specific, and inescapable. Verses 2 through 4 make the scope of that attention almost uncomfortably concrete: sitting down, rising up, a thought perceived from a distance, a path and a lying-down searched out, a word not yet on the tongue already known. The psalm is not primarily an argument for the doctrine of omniscience; it is a description of what it feels like from the inside to be known that way, and its emotional register (climaxing, in the verses beyond this lecture's citation, in "such knowledge is too wonderful for me") is worship, not textbook definition.

This matters for how the doctrine should actually be taught and preached. A God whose omniscience is presented as a large stockpile of facts is a God about whom omniscience is an interesting true statement. A God whose omniscience is presented the way Psalm 139 presents it is a God from whom, as the psalm goes on to say explicitly, there is nowhere to flee — and this can be read, depending on the state of the reader's conscience, either as the most comforting fact in the universe or the most alarming one. Hebrews 4:13 supplies the New Testament's own gloss on exactly that ambivalence: "There is no creature that is hidden from his sight, but all things are naked and laid open before the eyes of him to whom we must give an account." The verse does not stop at "God knows"; it moves immediately to accountability, which is Hebrews' own signal that omniscience, biblically stated, is never merely descriptive.

Open theism's alternative, stated fairly

Open theism, associated principally with Clark Pinnock and Gregory Boyd among contemporary evangelical theologians, denies one specific piece of the classical doctrine: that God's knowledge of future free creaturely choices is exhaustive and settled in the way God's knowledge of the past is settled. The argument is not that God is ignorant, careless, or limited in the way a finite creature is limited. The argument, in its most serious form, runs like this: if a choice is genuinely free in the libertarian sense — meaning the agent could, all factors held constant, have chosen otherwise — then there is, at the moment before the choice, no fact of the matter yet about which way the choice will go. On this view, saying "God does not yet know what Sarah will freely choose tomorrow" is not a statement about a gap in God's knowledge, the way "the professor does not know what is in the sealed envelope" is a gap; it is a statement that there is, strictly speaking, nothing yet there to be known, because the fact will not exist until Sarah's free choice brings it into being. Pinnock and Boyd argue that this framework, far from diminishing God, actually protects two things classical theism has trouble holding together: a God who takes real risks and can be genuinely surprised, disappointed, or pleased by how history unfolds (rather than merely narrating a script he already wrote), and human freedom in a strong, libertarian sense unconstrained even by God's own prior knowledge of the outcome.

Open theists point to biblical texts that, read at face value, seem to describe God discovering something, changing his mind, or being surprised — Genesis 6:6 ("Yahweh was sorry that he had made man on the earth, and it grieved him in his heart") is the paradigm case, and it will receive full treatment alongside the classical Reformed and Arminian responses to it in Chapter 7. This lecture's task is only to make sure you can state the open theist position accurately, in its own terms, before the extended debate; it is a live position held by serious, professing evangelical theologians, not a fringe error, and Trap 6 in this course's own working notes exists precisely to keep positions like this one from being handed to you as cardboard.

What is actually at stake

It would be a mistake to treat this as a purely academic dispute about the metaphysics of time and freedom, interesting only to philosophers. Classical theists worry that open theism, whatever its motivations, ultimately compromises the confidence believers can place in God's promises about the future — if God does not yet know what free creatures will do, then predictive prophecy, providential guarantees like Romans 8:28, and confident intercessory prayer for another person's free response all rest on somewhat less certain ground than the classical tradition has historically offered. Open theists respond that classical theism's confidence comes at the cost of a God who cannot be genuinely responsive to prayer or genuinely moved by a changed heart, because everything, including the prayer and the change, was already exhaustively known and, on stronger versions of the classical doctrine, already decreed (a connection this lecture only flags — the divine decrees are Chapter 8's subject, not this one's). Both sides think the other's God is diminished in some way that matters pastorally, not merely philosophically, and that is worth sitting with rather than resolving here.

Both sides affirm exhaustive knowledge of the past and present. The dispute is narrower — and sharper — than it first appears.

5. Going to the Sources

• Psalm 139 in full (not only verses 1-6) — the psalm moves from being known (vv. 1-6) to being inescapably present to God (vv. 7-12, previewed in Chapter 3's lecture on omnipresence) to a prayer for God to search the psalmist's heart (vv. 23-24), which is worth noticing as the psalm's own final move: knowledge of this kind becomes, for the psalmist, something to ask for more of, not merely a fact to affirm.
• Thomas Aquinas, Summa Theologiae I, Q. 14 ("The Knowledge of God"), articles 1-13, especially article 13 on God's knowledge of future contingent things — the single most sustained classical treatment of exactly the question this lecture opens.
• Gregory Boyd, God of the Open Future (or the shorter statement of his position in the four-views volume Divine Foreknowledge), for open theism stated by one of its own leading contemporary advocates rather than by its critics.