The nature of fire, wind, water, and land, is like that of space. It is the absence of true knowledge that draws distinction between them.
अग्निमारुततोयानां वर्णाः क्षितितलस्य च। आकाशादवगृह्यन्ते भिद्यन्तेऽतत्त्वदर्शनात्॥