Life isn't meaningless just because there is no God and no real purpose for our existence by the standard of some higher intelligent creator.

Life's meaning is what you give it.

The "meaning of life" is completely subjective. It's different things to different people.
As it should be.

Life, imo, is NOT meaningless, it is a process of growth, learning, comprehending,etc, etc, that everything must go through, LIFE is what you make of it and what you do with it.

The meaning of life is to find meaning

Out of an estimated range of from two million to two billion species alive on Earth today, apparently only one suffers because of a perceived lack of meaning in life. This suffering is clearly manufactured in the mind of that one species, and so the relief from this suffering is equally clearly to be found in that same mind.

What’s meaningful to all the other species is finding food, safety and suitable mates. Since none of these things are guaranteed for them, they have all the meaning they can handle.

H.sapiens figured out how to more or less automate the meeting of these needs so successfully that they have forgotten what it’s like to not have access to food for three weeks or human contact for a year. We don’t have a deficit of meaning; we have a mind-numbing surplus.

I think you make some good points. I would say that meaning is heavily driven by relationships. For instance, as a father, many of my reasons for doing things go back to my desire to provide for my daughter, nurture her, and protect her. Perhaps that goes back to biology.

But on top of that, I think human beings are able to cooperate on the basis of grand narratives, and to be part of something larger, as you say. The historian Yuval Noah Harari has made a lot of this point in his books. If you want a large population of people to cooperate in a particular direction, you have to get them to agree it is worth doing, and you do that by offering a compelling story of why it should be done.

Certainly religions have taken advantage of this a great deal, but so have governments, and also other emergent systems of thoughts with no single author (I'm thinking of things like democracy and money).

Meaning - what meaning.
This planet we call earth is just a dust speck in the universe and each and every one of us is just an assemblage of atoms that form a human.
Whether you are rich or poor, find a cure for cancer, or do nothing more than exist as a beer and pizza processing plant is irrelevant to the rest of the universe.
So each day find something to smile and laugh about, something to make the adrenalin pump, and enjoy whatever you can about being alive
One day you will cease to function and become a lump of meat. Your atoms will begin to recycle into other forms of life and whatever you were is forgotten.

Yes, I can see what you mean. If we lived indoors in isolation from birth and were deprived of sensory stimulus, with no contact with other living things, either human or animal, then it would be very difficult in seeing any meaning to our lives, but that, of course, would never happen. Because we have the stimulus of interaction with nature and other humans, our lives take on meaning. This meaning by definition must differ from individual to individual, but we can never know how meaningful another’s life is, only our own. I believe the more we interact with other humans, and enjoy man’s endeavours in the fields of art , music and science, along with the beauty of the natural world and it’s flora and fauna, the more meaningful our lives become,

Astute observations. Yes, the substance that comes to comprise our personal "meaning" comes from the outside. As Jean Piaget pointed out, we are biological organisms in constant interaction or exchange with our environment. We are constantly taking inputs from that environment, and, just as we build cellular structures to incorporate and use those inputs, we do so with our minds. We are constantly taking (passively or intentionally) from the our environment and building them into cognitive structures and schema (patterns of action) which we use to build cognitive structures which constitute our sense of "Meaning."

"Something larger"? How about a tall guy that makes me laugh? Your attempts to "subtly" try & make me think "spiritually" are laughable, and about as subtle as an anvil falling on my foot.

Meaning is what humans impose on their world to help them cope.
Life in itself is meaningless, we have to give it meaning through knowledge and experience.

I think it's a mistake to try to find some "meaning" or "purpose" to life. Life is to be lived. We are meant to simply try to enjoy living. By this, I don't mean a constant, mindless pursuit of pleasure, but rather the point of existence is essentially to try to enjoy it. If one is perpetually unhappy or miserable, that seems to me to take much of the point of living away. Just a thought.

I'd like to add that I do realize that individuals do need purpose or meaning in their lives. But I consider purpose to be something that each individual needs to discover for him/herself. I don't think there's any overall grand meaning that is the same for everyone.

LIfe is potential. It has no meaning beyond what we can make and understand of it. We are born, we live, we suffer, we die. To believe there's meaning is to suggest systems of rewards and sanctions: eternal life and damnation, or reincarnation. The former are dreadful, the latter is boring.

I find life as an atheist hopeful, joyous, and meaningful.

The chemical process that we call life has no value IMO. Blind, robotic mechanistic events with no awareness and no free will certainly can’t be valuable, and sure enough, we see that organic bodies live only for awhile and then they die. Sometimes they die en masse. And while they are alive they are prone to hardships and suffering.

I see two ways of looking at it. You can consider all organisms collectively as a river of life, a single entity that goes on flowing even though individual organisms are temporary. If I think of myself as the river instead of as an individual body then in my mind at least I become something more enduring and substantive. I hunt mammoths—I invent airplanes—I travel in space—I make love with sexy women.

But there is something else—something intriguing. Many people seem to think that conscious awareness springs only from brain activity—from the firing of neurons. To save my life I cannot fathom such a thing. For me the fact that we have conscious awareness gives life immense meaning and value. The meaning might be a mystery but meaning there is. The fact that we can have this conversation shows me there is value. The meaning of reality is cloaked in darkness but it is a dazzling darkness, full of joy and hope!

Edwin Schrodinger:

“Consciousness cannot be accounted for in physical terms. For consciousness is absolutely fundamental. It cannot be accounted for in terms of anything else.”

The meaning of life is split in my opinion. It is split into two categories logic and emotion. Logically it would be to reproduce and keep our species alive. Emotionally it is to LOVE. There are many forms of love and endless things to love. To live a happy and fulfilling life you must Love. You can bring both sides into balance by having a family and with that you bring more love into existence. It is a fractal effect and without it we will cease to exist.

What about the opposite case using a "Given that life is not meaningless...."

I can agree with this. Facing it differently, too many people want to turn over their meaning in life to an imaginary being. This is because they have no meaning in life or have not realized that they themselves give their life meaning. Life is what you make it. Life itself has no meaning. When you bestow meaning upon life that is when you start making things up.

If by saying "life is meaningless" you mean "life has no inherent / given / found / bestowed meaning" then I'd agree with that. But then, it never has. Some people have just asserted without evidence that it has.

People have always decided what they care about and/or enjoy and then figured out how to manage hedonic tone around that and in this they find meaning and purpose for themselves. This however says nothing about the locus of where the meaning is coming "from". Meaning is an abstract idea, not a thing-in-itself. It's not "out there" or "in there" waiting to be discovered. Its (apparent) location is quite irrelevant.

Meaning is an emergent byproduct of interacting with your environment and your own thoughts and feelings and those of others and then being organically attracted to whatever mix of these things you find both compelling and doable, and that reinforces itself by being rewarding more often than not (and more often than other things).

In this it is, ironically, somewhat random. At a particular period in my life, for example, I was a rabid classic film collector. Many people don't find that interesting, let alone compelling. And my relationship to that has changed; today I find software design and development as both vocation and avocation more compelling and accessible for various reasons. In another decade it may well have shifted again.

I do not experience my inner life as a void that needs filling or some other form of remediation. I think some people do have that subjective experience but I never have, honestly. Nor have I felt dependent on other actors to feel complete. They can certainly be interesting and helpful and kind, but they can also be banal, vulgar, capricious and antagonistic. I accept what is offered me by others and my environment but don't count on it. I offer what others want that I'm able to provide out of any sort of personal overflow. I don't think it has to be more complicated than that.

If I feel disappointed, frustrated, or bored, then I take that as information that I need to change things up a bit. Maybe some activity or interest or relationship no longer serves me well or has become toxic or harmful in some way. Maybe I need more self awareness around my thoughts so I can better appreciate what I have rather than focus on what I don't. Maybe I need to change how I frame my thoughts or change certain habits. Maybe I need to let go of resistance or control in one or more areas.

I don't see how a greater purpose or higher self is a necessary entity to any of this. If anything, I've observed that people are subject to ego inflation around things like this. I don't need to be somebody, or be remembered, or appreciated in any overwrought sort of way, or part of some great scheme of things in order to find my life meaningful. I certainly used to feel more this way, but I have found such thoughts to be the product of operant conditioning, not some inherent property of reality.

Life is it's own meaning. Or, to live is meaning itself. To look beyond this is like an eye looking for itself.

Life does not need meaning to have value, if you understand that life itself has value then that understanding is all the meaning it needs.

Since life is all you have it matters not if it has meaning or not, since there is nothing more, and that applies even to the theist, since even if there is another life which is not entirely independent of this one, then you have nothing more than this one with which to affect the next life.

Relax and be cool!

To me, asking for the "meaning" of life is trying to attribute a value, ability, something that says "life" has purpose. The things that drive "life" , the need to survive, and the things that drive that need....don't really have a"meaning".

We depend all the responses of our senses to give us an idea what is going on outside ourselves. these things are only perception how we choose to perceive is clearly an internal mechanism. there are the those who Find the meaning of life and isolation.

there is no truth only perception

change your perception change your truth

What is good? What is truth? What is beauty? What is wisdom? This is the only conversation worth having.