Meditation not linear I've heard it said that meditation is not a linear path and that every time you sit is like the first time but that you get better at sitting for the first time.  If this is the case and you don't actually make gains in a linear way then can it also be said that if you stop doing it that you will not go backwards or lose what you have learnt because you didn't go anywhere to begin with?
Meditation is not linear, as it involves the whole of ourselves. There is one part/side of us that is connected to our rationality, logic, linear thinking, and understanding. The other side of us is connected to feelings, nurturing, caring, compassion, love, and all the emotional qualities. This is how our right and left hemisphere in the brain is programed. The left side of the brain processes information in a linear manner. It processes from part to whole. It takes pieces, lines them up, and arranges them in a logical order; then it draws conclusions. The right brain however, processes from whole to parts, holistically.

Intellectual understanding about meditation is never the same as the actual experience of it.  It is similar to that of having to bite into a mango to know its taste. We can read everything that there is about a mango – that it can be sweet, delicious, soft, etc. but we cannot imagine its taste unless we get the feeling of the mango on our tongue and have the personal experience. Then we can no longer debate whether the mango is sweet or not, because we have experienced the truth. This is the difference between just thinking or thinking coupled with the experience of feeling. 

Once the meditator goes beyond the second Jhana level, the internal thinking comes to a stop, and memory of past experiences never come up.  From there on there is no such thing as a linear process.  From there on it is total awareness in staying with the breath. This is being one with your meditation.   This is ekaggata, as in ekaggatarammana, oneness of preoccupation, or singleness of preoccupation; and ekaggatacitta, singleness of mind. This kind of oneness applies to all levels of jhana. It means being focused on one thing, like the breath. You stay steadily focused on it, at the same time making it the one thing filling your range of awareness.