Is knowledge in part a priori?

I had this debate with Starless, but he ended up forfeiting. I was really disappointed because I was introducted to a lot of good material in this debate, and was devastated that we couldn't finish. It would be great if people could give me their....
1) Thoughts on the topic
2) Thoughts on my argument
3) Thoughts on Starless's argument

http://www.edeb8.com/debate/That+our+acquirement+of+knowledge+is+in+part+a+priori

Blackflag: In part it is. For concepts in math, like arithmetic and geometry are all due to our intuitive thoughts about space and time, which is wholly a priori (because a posteriori experience would be contained within space and time). But the other part, and this in my opinion is much more significant than a priori knowledge, is wholly made up of a posteriori knowledge. The knowledge of existence of other beings, cause/effect etc.

I'll read your arguments later

My argument was that true knowledge could only be attained through sensory expierience.