Is a dog from the present considered to be the same thing as the same dog 1 sec in the future? What are the distinctions philosophers tend to make when we refer to the same thing at a different time. What are the various views on this and has there been a consensus on how we should treat them? How do we assess a truth position when the elements being judged exist in different times?

  • 1
    Hi, welcome to philosophy SE. Broad questions of this sort do not really fit our format, and are already addressed by online encyclopedias, e.g. SEP Identity Over Time. We take more specific and pointed questions that come up after such general reading.
    – Conifold
    Sep 26 '19 at 17:50
  • 1
    Everything is constantly changing. Even space, as you walk, never looks the same. Nothing is the world is static. You can say, "Now the world is this." But as you move the world immediately looks different and your previous statement is no longer true. The solution is constant awareness. Direct perception of reality. Sep 26 '19 at 18:06
  • 3
    This sounds a lot like Ship of Theseus - Wikipedia and the difference between substance and essence. Sep 26 '19 at 18:57
  • 1
    @RayButterworth Your link's messed up; it leads to a different site every time.
    – Nat
    Sep 26 '19 at 19:18
  • 2
    @RayButterworth Nevermind, turns out that I was just clicking a different link each time.
    – Nat
    Sep 26 '19 at 19:25

tl;dr- Whether or not something is the same from one moment to the next depends on the model framework; either model is valid. As for the continuity of one's identity, that's an emotional concern not determinable by logic alone.

To quote this answer:

Summary: Equality is context-subjective, sameness isn't so much.

Things are equal in some sense when they're interchangeable in that sense.

Things are the same when they're equal in all ways that we care to identify.

So, something is the same from-moment-to-moment if we don't care to identify the moment in which it exists as a meaningful distinction. I'm trying to stress that "in all ways we care to identify" part, as the choice of ways that we care to identify is subjective.

I mean, we can take two views here:

  1. Things exist at a moment in time, such that things that exist at different moments in time are distinguishable.

  2. Things can exist across moments in time, such that when we point to a thing at different moments in time, we're merely pointing at the same thing in different ways.

Both are consistent and therefore valid.

Analogy: Is 1+1=2 or 1+1=10?

Say that someone asks if

  • 1+1=2 in decimal (Base-10); or

  • 1+1=10 in binary (Base-2).

What'd be the answer to that question?

They're both valid! We can say that 1+1 is either 2 or 10, depending on that frame; so long as we're consistent, it's all good.

Likewise, if we ask if a dog is

  • the same in a second from now; or

  • different in a second from now;

both'd be valid. We can say that it's either, depending on our frame, as long as we're consistent.

Of course, we can force errors. For example:

  1. It'd be wrong to say that 1+1=10 in decimal.

  2. It'd be wrong to say that a dog is the same in a second from now in a frame in which we say that things exist at precise points in time.

Those would be examples of consistency errors.

Related: Do people die every moment?

I think people sometimes wonder about the continuity of their personal identity; are people the same consciousness from-moment-to-moment?

From a scientific perspective, it's equally valid to say that you are or aren't, so long as the meaning of those descriptions is understood consistently. This is, there's no scientific reason that you have to see it either way.

The big question is how someone self-identifies. This is, do you care to perceive yourself as the same thing from-moment-to-moment; or, do you care to distinguish your identity across time in some way? Unfortunately, logic isn't going to tell you how you should feel; that's up to you.

That said, you can appreciate both models. This is, you can see your[-temporal-]self as dying at each moment while seeing your[-timeless-]self as existing across time. Then you can be upset about one while happy about the other. I mean, there's no reason that your emotions have to be rooted in a single perspective.

  • Tried to split a larger answer up into two posts on different questions, to avoid doing a super-long answer again. =P
    – Nat
    Sep 26 '19 at 21:39
  • A set of criteria is a set of criteria. Equal according to a set of criteria we want to consider or the same according to all the criteria we want to consider. This is a distinction without a difference. Both terms are entirely context-specific. When we use them both in the same context, we have to tell them apart, and it is not always 'the same' that is the more specific one.
    – user9166
    Sep 26 '19 at 23:46
  • @jobermark While everything's ultimately subjective, "equal" is more subjective than "the same". Examples: (1) In languages like Java/C#, we acknowledge that different objects (i.e., those stored as distinct entities in a computer's memory) can still be .Equal() despite not being the same. (2) People can be equal under the law without being the same under the law. (3) In physics, two forces can be equal without being the same force. (4) In math, two expressions can be equal without being the same, e.g. 1+1 and 2.
    – Nat
    Sep 26 '19 at 23:51
  • When there are no rules, you can invent or discern whatever rules you want. But this is not a rule. Most people would consider two copies of the same picture the same but not equal. Things can 'be the same' by belonging to the same class and will not be considered equal. Two forces can also be the same force in different degrees and thus not equal.
    – user9166
    Sep 26 '19 at 23:54
  • @jobermark Most people might find the phrase "equal pictures" to be strange, but if you asked someone to assess equality, they'd likely find the same picture to be equal with itself despite the unusualness of the question. (Unless you're arguing that people would assert that the same picture is unequal to itself?)
    – Nat
    Sep 26 '19 at 23:55

Not the answer you're looking for? Browse other questions tagged or ask your own question.