Do You Ever Stop to Ponder Your Thoughts?

Do thoughts even exist at all? Everything we call 'real' has a quality of dimension. Size, shape, weight, color, texture. Sometimes our thoughts may weigh heavy on the spirit, but it's all so conceptual and lacking in any definite, observable reality. Can we prove our thoughts exist or must we accept on faith alone that which we can never see, touch, or taste?

Thoughts...?