This is a tough question for me. When I consider these types of questions I try to remember several things:
1. The difference between Eastern and Western culture in the realm of spirituality is considerably different. It is tough for me to consider any response which equates Eastern spirituality with Western spirituality.
2. Old Japan had a nationalized religion. Religion was embedded into the culture of of Japan. I think it hard to consider any response which does not account for that consideration.
3. Religion is not spirituality is not philosophy is not principle. These terms are not inter-changeable.
I think ultimately historians and interpreters need to weigh in on this issue to create an apples-to-apples comparison. I am neither a historian nor an interpreter.
The leading response for me at this time is that all martial arts prioritized practicality over philosophy. The arts were developed for warriors and first and foremost they needed to work. We now live in a [relatively] peaceful time and have the luxury of study an art for purposes other than combat. The art is the same, but we are allowed a freedom to choose for what purpose we are studying it. However, I believe you cannot perform good aikido without learning and transcending the martial aspect of the art.
I training with several seniors whom I respect, I have noticed a philosophical and spiritual awareness that takes off the harsh edge to their interaction with me. They do not bring a fight, so we do not have to train to fight. They still have the martial intent and in an instant they can introduce the fight to our interaction. I can honestly say that for those whose only purpose in training is the spiritual side and whose education never included the martial side, their technique feels hollow and dependent upon collusion from their partner. It's great dance, but not a martial way.
Truthfully, I have never seen a compelling argument that O'Sensei ever advocated aikido to be anything other than a collection of principles, to be integrated into one's spiritual and personal belief system. In that sense, we seem to infer aikido has a spirality and religious belief system, rather than depending upon ourselves to integrate the principles into our belief systems.
Well said, nice post!I totaly agree with you.I hope that my posts are making the same sense.You see, english is not my mother tongue...