Bias

Science is based on measurement.

Every measurement comes with some degree of bias.  The bias may be inconsequential, or be so large as to completely hide meaningful results.

Human thought has bias.  And, likewise, it may be inconsequential, or so large as to complete hide any meaningful approach towards reality

The human mind and human emotion are both our assets and huge liabilities at finding truth.   The biases they bring are generally undetected underappreciated.