In the 17th century, European academic study was mostly based on classical authors and rote exercises. Scientia also called philosophy encompassed many fields of study, and Theology was the Queen of Sciences. What we today call biology was described as natural philosophy and later as natural history.
Observation and experiment
Natural Philosophers, when they endeavour to give an Account of any the Works of Nature by preconceivd Principles of their own, are for the most Part grossly mistaken and confuted by Experience; as [Ray gives an example of such error in a simple matter of anatomy] obvious to Sense, and infinitely more easie to find out the Cause of, than to give an Account of the Formation of the World.
Wisdom of God p.45
Dried plants unless excellently well conserved I dare not rely upon. I know how apt I have been to be deceived by them.
12 May 1685, Further Correspondence p.146
Science as an historical adventure
It is an age of noble discovery, the weight and elasticity of air, the telescope and microscope, the ceaseless circulation of the blood through veins and arteries, the lacteal glands and the bile duct, the structure of the organs of generation, and of many others-too many to mention: the secrets of Nature have been unsealed and explored: a new Physiology has been introduced ... To quote the great Boyle, I predict that our descendants will reach such heights in the sciences that our proudest discoveries will seem slight, obvious, almost worthless. They will be tempted to pity our ignorance and to wonder that truths easy and manifest were for so long hidden and were so esteemed by us, unless they are generous enough to remember that we broke the ice for them, and smoothed the first approach to the heights.
Quoted in Raven, p.255
Who were the scientists?
In the 17th century, sciences such as biology, chemistry and geology were not university subjects, and early scientists were mostly amateurs working in their spare time. Scientists, or 'philosophers', were not employees of universities and companies. A few were university fellows in other subjects, many were aristocrats, gentry, physicians (doctors) or clergy. Most had wide interests. Ray worked in botany and zoology, but was also expert in languages, geology and theology.
Ray wrote in 1660 in the preface to his Cambridge Catalogue:
We would urge men of University standing to spare a brief interval from other pursuits for the study of nature and of the vast library of creation so that they can gain wisdom in it at first hand and learn to read the leaves of plants and the characters impressed on seeds and flowers and seeds. Surely we can admit that even if, as things are, such studies do not greatly conduce to wealth or human favour, there is for a free man no occupation more worthy and delightful than to contemplate the beauteous works of nature and honour the infinite wisdom and goodness of God.