Suppose that everything that is considered as living individual suddenly dies out. What would happen to matter if now there is nobody who can think about it?

  • There are several presuppositions in your question. Why would you think that something would happen to matter, if we went extinct? Why is thinking necessary for reality? Also, it's not clear what kind of answer you're expecting. If you're asking about answers to this questions that have been given in the past, maybe you could rephrase your question in that regard, to make it more constructive.
    – iphigenie
    Jun 23, 2013 at 9:00
  • Related: Idealism
    – user3164
    Jun 23, 2013 at 16:44
  • since you will never die (at least you will be unable to detect it), the question is meaningless
    – Bulat
    Jun 23, 2013 at 20:34
  • 2
    One could make an inductive argument for its continued existence. Living creatures die all the time, and matter continues to exist. By extrapolation, extinction of all living things would probably have the same null effect.
    – David H
    Jun 24, 2013 at 19:19

4 Answers 4


Since one answer has provided the idealist perspective, I'm going to discuss its polar opposite: Logical Positivism. Before I do that, though, an important disclaimer is that despite logical positivism's status as the paradigm of natural sciences, it has long been dying in philosophy and is far from a popular position at the present. However, it is historically significant and a useful juxtaposition with idealism.

The primary principle of logical positivism is that apart from the fundamentals of mathematical and linguistic logic (hence "logical"), all truths must be derived from empirical observation.

Perhaps the biggest consequence of this is that to a logical positivist, if the answer to a question does not have any observable effect, then that question is meaningless. Thus, the question "does an inert metaphysical entity exist" is meaningless, because regardless of the answer our observations in the physical world will be precisely the same. The same physical observations means the same truths in logical positivism, so the answer to the aforementioned question becomes irrelevant.

In the same way, a logical positivist would call your question meaningless, because whether or not objects exist when nobody is around, they always exist when someone is observing (at least in our experience), so the answer has no bearing on empirical observation. In terms of logical positivism, it's pointless to ask whether an unobserved object exists or not, precisely for the reason that nobody is looking at it. Regardless of what happens when everybody is dead, our observations won't change by definition of the situation (we only observe things when not everybody is dead), and so the question becomes meaningless.

Of course, a big objection to all this is that these things should matter, and this is part of the reason logical positivism isn't doing so well. In some ways it dismisses ideas because "they don't affect me" when lots of philosophy is the pursuit of knowledge for its own sake, regardless of practical implications. On the other hand, logical positivists generally take the hard-line that in truth these things are literally meaningless because truth depends fundamentally on empirical observation.


This thought experiment is called to be Berkeley's:

If a tree falls in a forest and no one is around to hear it, does it make a sound?


Philosopher George Berkeley, in his work, A Treatise Concerning the Principles of Human Knowledge (1710), proposes,

But, say you, surely there is nothing easier than for me to imagine trees, for instance, in a park [...] and nobody by to perceive them. [...] The objects of sense exist only when they are perceived; the trees therefore are in the garden [...] no longer than while there is somebody by to perceive them."

A Treatise Concerning the Principles of Human Knowledge, 1734. section 45.

From this quote, it looks like he says that matter doesn't exist when it isn't perceived. Or, in Latin:

Ecce est percipi ― To be is to be perceived

However, then Berkeley wonders (paraphrased): how is it possible that when I go to work, and come back to my home in the evening, my house still exists? There must have been some moment nobody perceived it... That's the point that God enters Berkeley's philosophy: because God always perceives everything, matter can still exist even though there is no human being to perceive it.

Do keep in mind that this is just one opinion, and other philosophers may or may not think different.


For the overwhelming portion of the history of the universe as we understand it, there were no living organisms. However, now that we are around to perceive it, we can judge that physics carried on just fine before anyone was around to watch some tiny part of it. We should therefore assume that if we all die off, matter and physics and all will keep going just as it had.

(Note that philosophical questions of this sort were raised long before we had an understanding of the history of the universe, so historical answers were at times more creative than this.)

  • How do you know that the world existed before you existed?
    – user2953
    Jun 24, 2013 at 15:03
  • @Keelan - Ah yes. How do you know you existed before you read my answer?
    – Rex Kerr
    Jun 24, 2013 at 15:05
  • @Keelan - there is evidence that the world existed before I (we) existed. That evidence could be an elaborate staging to trick me (us) into believing a complex history that never happened, or it could be the actual result of history. Explaining the elaborate staging trick is infinitely more difficult than explaining a universe that predates me (us).
    – obelia
    Jun 24, 2013 at 16:49

Suppose that everything that is considered as living individual suddenly dies out. What would happen to matter if now there is nobody who can think about it?

Under my pagadigm (A variant of positivism) it would still be around. Are you working from a paradigm that requires thought for something to exist?

  • I would dearly love to know why this was downvoted.
    – shieldfoss
    Jun 24, 2013 at 10:01
  • 1
    Probably because the only thing you said was your opinion and the answer is therefore highly subjective. Answers are supposed to give more than that. Please check out how to write a good answer
    – iphigenie
    Jun 24, 2013 at 12:53
  • Interesting idea. Still, even Kant's writings are just his opinion, so I think I will leave it up, perhaps he will find my opinion relevant.
    – shieldfoss
    Jun 24, 2013 at 12:54
  • 2
    Yes, that is true. But it's not what this site is for. Please read the guidelines. "Please note that this site is not a personal blog or a pulpit for you to express your own personal philosophical beliefs. This is a Q&A site for examining ideas and concepts in the field of philosophy. It's OK to have opinions (even those that might differ from the "mainstream"), but you need to express them in a constructive way."
    – iphigenie
    Jun 24, 2013 at 13:02
  • 1
    Mm, I get that. I will write up a proper answer tonight, sourced and referenced.
    – shieldfoss
    Jun 24, 2013 at 13:26

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