62. The Existence and Nature of Time

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Lecture Notes

Main Topics #

• The Paradox of Time’s Existence: Time exists, yet its constituent parts (past and future) do not exist, and the present moment (now) has no duration
• The Problem of the Now: Whether the now remains the same throughout time or is always changing, and the paradoxes either position creates
• Time and Continuity: How time’s infinite divisibility relates to the continuity of motion and magnitude
• Before and After in Multiple Senses: How ‘before’ and ‘after’ apply to place, motion, and time in hierarchical fashion
• The Analogy to Points and Lines: Why time cannot be composed of nows just as lines cannot be composed of points

Key Arguments #

The Existence Problem #

• The past has come to be and no longer exists
• The future will be but does not yet exist
• The now (present) cannot have duration—if it had any length of time, it would contain before and after, making it not truly present
• Therefore, time appears to be composed entirely of non-existent parts
• Yet time clearly exists in some way, though “barely and darkly” (cumque)

The Problem of the Now: Two Impossibilities #

If the now always remains the same:

• There would be no time at all, as everything would be simultaneous
• Aristotle’s lecture, Plato’s lecture, and Berquist’s lecture would all exist in the same now
• This violates the principle that no limited divisible thing can have one limit (a line has different endpoints, a period of time has different boundaries)

If the now is always different:

• When does the present now cease to be? It cannot cease when it is (for then it would still be)
• If it ceases in some later now, there must be time between the present now and that later now
• But if there is time between them, there are infinitely many nows in between (since there is no “next now”—any two nows have a now between them)
• Therefore, the present now must coexist with all those intermediate nows, which is absurd

The Analogy to Points on a Line #

• Just as there is no “next point” on a line (between any two points lies a line, hence potentially infinite points), there is no “next now”
• If two points do not coincide, there is always a line between them; if two nows are distinct, there is always time between them
• Continuous things cannot be next to each other with nothing of the same kind in between
• Therefore, the present now cannot cease to be at a determinate later now

The Relationship Between Before and After #

• The primary meaning of “before” comes from spatial location (place)
• The meaning of “before” in motion is led back to the meaning of “before” in place
• The meaning of “before” in time is led back to the meaning of “before” in motion
• This hierarchical relationship shows how these concepts are related but not simply identical

Important Definitions #

The Now (Present) #

• The division or limit between the past and the future
• Not a part of time (as a point is not a part of a line)
• The only thing that is fully actual in time
• If the now is understood strictly (with no duration), it contains no time at all

Continuous #

• That which is infinitely divisible (divisible forever)
• Alternatively: quantities whose parts meet at a common boundary
• Magnitude, motion, and time are all continuous

Touching, Continuous, and Next (Distinctions from Book VI) #

• Continuous: sharing a common limit
• Touching: limits are together but not shared
• Next: nothing of the same kind in between (though other kinds of things may intervene)
• These distinctions will be more fully explained in Physics Book VI

Examples & Illustrations #

The Cone Problem (Democritus) #

• If a cone were composed of stacked circles, cutting it parallel to the base would produce two circles
• If these circles are equal, the cone would be a cylinder (contradiction)
• If they are unequal, the edge would not be straight (contradiction)
• Application to time: This demonstrates why time cannot be composed of nows—continuous things cannot be built from indivisible parts

Walking from Here to a Hat #

• When walking from one location to another, the motion that has already occurred no longer exists
• The remaining motion has not yet occurred
• So how much motion is ever actually present in the now?
• If any motion were present in the now, one would have to be in two places simultaneously
• Conclusion: Motion, like time, barely exists

Pancakes Stacked as Cylinders #

• Pancakes have thickness (depth), so they can be stacked to create height
• But circles have no depth, so stacking circles creates no height—only a circle
• You cannot make a three-dimensional shape from two-dimensional shapes by stacking them

Lines Compared to Lines #

• A cylinder cannot be made by packing circles one on top of another because circles lack depth
• Similarly, a square cannot be made by putting lines together because they lack width
• This reinforces the principle that you cannot compose continuous quantities from indivisibles

Thoughts and Numbers vs. Continuous Things #

• In a syllogism: “Every mother is a woman, no man is a woman”—there is a next thought: “No man is a mother”
• Between premises and conclusion, there is no intermediate thought—thoughts are like numbers (discrete)
• Therefore, thought is not continuous; there is a “next thought” just as there is a “next number”
• Significance: The reason can think about continuous things in discontinuous (numbered) ways, which shows reason is not a body

Dividing Numbers and Concepts #

• Numbers can be divided into odd and even with no division in between
• Plane figures can be divided into circular and rectilineal types with direct division to triangles, quadrilaterals, etc.
• There IS a next division in conceptual thought, unlike in continuous quantities

Notable Quotes #

“If no one asks me what time is, I know what it is. But if someone asks me what time is, I don’t know what it is.” — Augustine, Confessions

“One might suppose from these things that it either wholly is not, or that it barely exists, and darkly.” — Aristotle, Physics IV.10

“After the things just said about place and about the empty, there remains to go toward time.” — Aristotle, Physics IV.10 (with Thomas commenting on Aristotle’s suggestion of the difficulty)

“The knowledge of truth is in one way difficult and another easy.” — Aristotle, Metaphysics Book II

Questions Addressed #

Does time exist? #

Resolution: Time exists, but “barely and darkly.” Its parts (past and future) do not exist as present things, yet time is real because we experience change. Like a line composed of points that have no extension, time exists as a continuous whole even though the now has no duration.

What causes difficulty in understanding time? #

Resolution: The difficulty is in the thing itself, not in us. Time is one of those realities that “hardly is”—it has minimal existence. This parallels matter with its potency, which also barely exists. Understanding difficult things requires grappling with things that have tenuous being.

Can the now be the same throughout all of time? #

Resolution: No. If all nows were the same now, there would be no temporal succession—everything would be simultaneous. This contradicts the principle that bounded continuous things must have different limits.

When does the present now cease to exist? #

Resolution: This question creates a paradox. The present now cannot cease to be when it is. If it ceases in a later now, there are infinitely many nows between (since there is no next now), making the present coexist with all intermediaries—which is absurd. The resolution lies in recognizing that the now is not a part of time but a division or limit.