Now faith is the assurance of things hoped for, the conviction of things not seen. For by it the people of old received their commendation. By faith we understand that the universe was created by the word of God, so that what is seen was not made out of things that are visible. – Hebrews 11:1-3 (ESV)
We can see with our eyes that the physical world around us is real. Without faith, believing that the spiritual things we cannot see are real is impossible. Contrary to popular belief, the Bible does not teach us to have blind faith. True faith will never be led by emotions but based on the wisdom that comes from His Word.