In my post: Principles Against Some Common Fallacies...
5. 'Oneness' and 'interdependency' are mutually contradictory ideas and neither is central to Buddhism.
Interdependency exists, but is a special case, not a universal one.In the Abhidhamma section on conditional relations there are many types of conditionality listed and interdependence is one of them. The example given is the the three legs of a tripod are interdependent. If any one falls, they all fall. However, this is an unusual situation. Take one brick out of a wall and the others do not all fall down. The popular modern idea of interdependency rests upon the idea that in this case there will be a miniscule movement of all the other bricks, but this hardly proves the point. The Buddha was not talking about such philosophical fine points, he was talking about real life. Most dependency relationships are one way.
The modern idea no doubt owes something to the popularity of ecological concern. This concern is for good reasons, but ecology does not demonstrate inter-dependency either. Most ecological relationships are, again, unidirectional. The whole biosphere depends upon heat from the sun but the sun does not depend upon life on Earth. It is, rather, the inexorable one-wayness of things that makes the situation perilous. Ecological catastrophe is a possibility not because everything is interdependent but because some things upon which many other things depend might fail with those in the secondary dependent position not being able to do anything about it. Interdependency massively over-estimates the importance of the human capacity.
Often, 'interdependency' and 'oneness' are spoken of as though they were more or less the same thing. However, this is a loose and slippery way of speaking. Relationship, whether 'inter' or not, always requires at least two participants. The fact that two things are related does not make them into one thing. The cat and I have a relationship, but I am not a cat and she is not human, nor are we in any real sense a unity. She has her life and in some respects relies upon me, though she would get those resources from elsewhere if I were not here. Of course, interdependency can also be called codependency. When it is called 'codependency' it is 'bad' and when it is called 'interdependency' it is 'good'. Really, however, this is mostly just playing with words.
The Buddha taught that we are dependent and that it is therefore good to help and care for one another. Recognition of our dependent position is a ground of compassion, since we are all broadly in the same boat in this respect, but the actual situations are distinct and sharing a circumstance does not constitute a unity. In fact, recognition of such sharing is often the basis for realising that others do not deal with the same situation in the same way. This can be a personal liberation, since we all too frequently tend to assume that 'we have no choice' when this is not at all the case.
If all were 'one' there would be no dependency. This incidentally means that what we call self-reliance is also really a fiction. The ordinary usage of the term does no harm in general - we know roughly what we mean - but the self is actually not something one can rely upon. The type of person that we call self-reliant is somebody who is aware of the factors upon which he or she depends and has achieved some skill in managing them.
Given that each of us is a unique bundle of dependent factors, it is inevitable that, to an extent, whatever we do, we do it our own way. However, 'I did it my way' is not something to be particularly proud of, it is simply an inevitability. The liberated person will generally choose to do things in ways that have been long established as good. This is what being part of a tradition implies. However, they will also be capable of standing alone if necessary or appropriate if that is what is needed to bring some improvement in the world. Of course, in making such judgements we often err, but hopefully we learn from such errors as we go along.
In a community, we are not aiming for oneness, nor for interdependency as an ideal. In some respects there is interdependence and sometimes we are united in some purpose, but times of difference, individual initiative, providing for others in an unreciprocated way or receiving similarly are all also times capable of profit. The point here is really not to go to an extreme.
Interdependence is not definitional for Buddhism, nor is 'oneness'. They are occasional, passing circumstances.